study material - fmcet

Fatima Michael College of Engineering & Technology

STUDY MATERIAL AT6702-VEHICLE MAINTENANCE DEPARTMENT OFAUTOMOBILE engineering

SEM - VII

AT702

VEHICLE MAINTENANCE


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UNIT – I PART – A Introduction Although the modern automobiles have established an excellent reputation in regard to good service and reliability, there are a number of important items which require periodic attention or inspection if the car is to be maintained at its best over its useful period of life, with greater immunity to break down and with minimum expense to upkeep. 1. What do you understand by vehicle maintenance? Maintenance means keeping all the systems and features functioning as possible to the manufacturers original design intent tons. Maintenance helps the vehicle to start run and stop as the manufacturer intended, so that maximum amount of performance, reliability and service life are achieved. 2. Explain the purpose importance of maintenance. The purpose of vehicle maintenance can be summarized into: (i) (ii) (iii) (iv) (v)

To keep the vehicle in good running condition To keep the operation cost less To provide safety on vehicle operation To give feed back to manufactures for development and rectification To adhere to the legal requirements of vehicle operation.

After the completion of the recommended running in period for the new or reconditioned vehicle, and during the subsequent normal working period it is necessary to give maintenance attention to eat air specified items at regular intervals to ensure satisfactory operation and freedom from trouble. These routine maintenance is to be done according to the manufacturers instructions is the maintenance manual. 3. What is the mileage prescribed for first service? With the majority of vehicles, it is used to assume that at the end of the first 500/1000 kilometers miles if the vehicle has been driven below the stipulated maximum speed, the vehicle will have attained it proper working condition. 4. What are the faults found in vehicle by selling agent? The most important faults found in vehicles delivered by the manufacturers selling agents are: (i)

incorrect value stem clearances


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Fatima Michael College of Engineering & Technology (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) (x) (xi) (xii)

wrong ignition timing water leakage around windscreens wrong setting of carburetors wheels out of balance faulty door and boot locks incorrect front wheel alignment improperly adjusted brakes Non aligned head lamps Incorrect spark plug gaps Incorrect levels of lubricants and Insufficiently tighliened nuts, bolts and fasteners.

Once there faults are rectified, the vehicle need not require much attention apart from the routine check-up of fuel in the tank, water in the radiator, charging of battery, level of water oil etc. 5. What is the maintenance works carried out after covering first 1000km? At the end of the first 1000 km, the engine-sump gear box, back axle casing etc: are drained and filled up with recommended grade of lubricants. All cylinder head nuts are checked for tightness, and the inlet and exhaust manifoldness are also checked. All working joints of the vehicle viz carburetor dried pump clutch, brake mechanism joints are oiled well. The steering system and spring shackles are lubricated. The cooling system is checked for leakage. Spark plugs, and automatic ignition controls are cleaned. Fuel filters are inspected and wheel alignment and lightness are checked.

PART – B 1. What the types of maintenance and shortly brief/them. Types of Maintenance  Preventive maintenance or scheduled maintenance  Predictive maintenance  Breakdown maintenance or unscheduled maintenance Preventive Maintenance  It is a schedule of planned maintenance actions aimed at the prevention of breakdowns and failure.  Primary goal is to prevent the failure of equipment before it actually occurs  Preserve and enhance the equipment or vehicle reliability by replacing worn components before they actually fail. Preparation of checkup


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 One should have the good understanding of the entire system and parts involved in it.  Identifying the parts and the interval of which it has to be done.  Identifying what has to be done Maintenance Records or log  It is a journal or book of all maintenance performed on a particular vehicle. Each entry includes a date, mileage as of that day, details of about the type of work done, and who performed the service.  If also include receptor and a schedule for further maintenance.  It will clearly tell the frequency at which the oil changes, fire rotations, Brake inspections or replacements etc are done hence monitoring activity an be done early. Determining preventive Replacement Time

Figure: Optimum Age Replacement Model It can be seen that the corrective replacement cost increases as the replacement interval Increases. And the preventive maintenance cost decreases. On combining both cost we can get an optimum point that minimizes the cost. Checklist A check is a simple, usually usual, confirmation that the equipment or vehicle is ready for further use. A checklist gives us. The list components that as to be checked at regular interval time. It may be  Daily check  Weekly check


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Fatima Michael College of Engineering & Technology  Monthly check  Yearly check 2. Briefly explain the points to be taken care in establishing an automobile. Service station/workshop 1. Service enhance: The approach to the service reception should be smooth. 2. Reception/Diagnosis (Service adviser) (i) Warm and friendly Reception (ii) Careful listening to customer’s Requests correct diagnosis. 3. Filling Repair order and Estimates (Service adviser) (i) (ii)

Accurate preparation of Repair orders Clear Explanation of work and cost estimate agreement obtained.  Repair orders have log A and log B charts log A  log B – distance traveled, Fuel filling details  Rough Estimate should be given to the customer.  Service people should be allowed to service the parts which are not covered by the agreements. (gets signature from customer).

4. Work allocation/Instructions (Fore man / Technician) (i)

Work allocated for efficiency (considering technician skill level completion time-outside work required etc). Accurate work instructions (eg. Nature of problem). Repair procedure proper steps completion time etc).

(ii)

Upholstery Body Trim Fender

seat cover works Bonnet (Engine Compartment cover) (Wing) The panel above the wheel and side of the vehicle

5. Repairs (Technicians) (i) (ii)

Reliable work, quickly accomplished Work performed neatly, observing proper safety rules.

6. Final Inspection [Foreman / Chief Technician] (i) Quality of work checked (correct items Repaired) 7. Delivery preparation (Service Advisor)


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Fatima Michael College of Engineering & Technology (i) (ii) (iii)

Check on what work was done Clean inside and outside of vehicle Prepare Documentation

8. Delivery (Service adviser) (i) (ii)

Explain Details (work done, charges, spare parts) Receive payments

9. Post service follow-up (service Adviser) (i) (ii)

Check with customer Regarding work quality Enquire About customers satisfaction.

3. What are basic instruments needed for turning of petrol engine? 1. Compression Gauge

To measure compression pressure Busing identified Borden tube pressure Gauge is used.

2. Vacuum Gauge

Similar to compression Gauge. Contraction Takes place and goal is marked reverse. 0 – 10 .

If comp pr. reduced. or low

Gaskets, valve leak valve timing. Change of comp & comp Ring crack in the cylinder head warpage due to insufficient tightening of the head Bead is ground to avoid warpage.

3. Tachometer:Tachometer, - Engine rpm. Speedometer - Instruments linear velocity of vehicle Odometer - Distance trowel of vehicle Tripmeter - Reset (distance travel of vehicle) used in autos & Taxis. 4. What is the sequential procedure for tuning a petrol engine? 1. Loose spark plugs start Engine to Blow out carbon and dust, start-off Engine and Remove plugs. 2. Test Engine compression:3. If the comp. pr is less, perform Engine service that will Eliminate the trouble of the compression is alright Re-Install the spark plug. 4. Remove distributors cap clean it. Visually check for carbon tracks and carroded


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Fatima Michael College of Engineering & Technology terminals chips etc. Replace it if hot in good condition.  Spark due to current flow through ionized Gases (400v),  Lower part is aluminium alloy (10w tension).  Arc due to flow of current flow and material transfer and carry electrons with it.  The upper part(cap) is Backlight (high tension).  Due to carbon deposit – short circuit and spark Jumping  Any crack in the cap – makes short circuit cap can’t be Recondition – it should be Replaced. 5. clean and inspect distributor Rotor, if it is not in Good condition, 6. Inspect the high Tension Leads. If they are ached or insulation damaged replace them. 7. Check distributor centrifugal advance mechanism. 8. Test the vacuum advance mechanism. 9. Check distributor contact points and clean them carbon accumulation takes place. 10. Re-install Distributor cap and replace wiring.  Colour of surface indicate the status of cylinder. 11. Check Battery state of charge, water level and hold down clamps. 12. Check battery cables for damage corrosion and loose connections. 13. it the battery is overcharged or undercharged check the dynamo (Alternator) and regulator 14. check drive belt and Tighten or replace them as require  slackness in the belt lead to non-fn of generator or alternator  overtight lead to unwanted fiction wastage. 15. Check the intake manifold bolts for tightness to proper specifications. Even a slight leak will reduce engine performance 16. Check fuel lines for tight connections.  Possibility of air entering into the fuel line when pump is 17. Check the cooling system for water leaks collapsed hoses, correct, coolant level. 18. Check and adjust accelerator linkage.  Rubber bush gets flattened  It free play more less response

Can be adjusted In linkage 19. Check crankcase ventilation system.  Old vehicles have Breather pipe for the above purpose.


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Fatima Michael College of Engineering & Technology 20. Remove carbureter air cleaner and check choke value clean or replace air filter element if necessary.    

Day wet type filter Filled with oil Check oil level & moisture content Due to prolonged use devil is reduced

21. Check and adjust contact point dwell and ignition homing. 22. Adjust idle speed and mixture. 23. Check the lube-oil dipstick level.  Feel the consistency of lub oil and find the wheather the need for lub oil to be changed or not 24. Check the working of lights and horn. Adjust the head lamp for proper focusing. 25. Check steering system for easiness. 5. Write down the steps involved in servicing the ignition system with contact breaker points. 1. Clean, recap or Replace spark plugs. -

clean with wire brush check for cruel in insulation.

2. Clean and inspect the ignition coil. If the tower (Top) is cracked replace the coil. 3. Replace the primary wire (coil) to distributor and coil to switch it is broken make sure that the connections are clean and Tight. 4. Clean and inspect the distributor cap. 5. Examine the Rotor. 6. Twist the distributor shaft in the direction of rotations and release. It should snap back it if Does not the distribute advance mechanism must be repaired. 7. Inspect the contact points replace them it necessary check and set the gap. - 0.4 to 0.5 gap is maintained in the contact points. 8. put a small amount of cam lubricant (white silver lube) on the distributor com. 9. check and set the Dwell using a Dwell meter 10. Adjust the timing using a Timing light and Techometer 11. check whether the advance mechanism works using the timing light. 6. Briefly explain the procedure for servicing the spark plugs.


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Servicing of spark plug:1. Remove H.T wire from Spar plug to do this slightly twist the rubber protector boot which partially covers the fluid, to break the seal, grasp the boot and pull it away from the plug with a steady even pressure. 2. Mark each wire with the cylinder no.(user paper Tape). 3. Remove any foreign material from around the plug hole by wiping with a rag (or) Blowing air waste cloth. 4. Remove the spark plug and Gaskets and heap them in the order by the which they are Removed. An isolated plug showing an abnormal condition indicate that the problem is with that cylinder. 5. Wipe if the exterior of the plug and inspect for proper sealing. 6. Check for burned electrodes and dirty, foul (or) cracked insulators what does the sp face reveal? Fouled By soot

Condition Dull black, velvety carbon deposits

Indication  Clogged air cleaner  A/F mixture rich.  Electrode Gap more.  Cold plug used.  Insufficient voltage  Prolonged idling Fouled by oil Shining black wet carbon  A/F mix is rich deposit  Worn-out value guides.  worn-out cyl/pistion rings Over heated Insulator burnt whit with  A/F mixture loan pearly deposited of  Improper beating of plug metabolic parts eroded  hot plug used. electrodes.  Improper closing of values  Engine overheated 7. If new plugs are installed make sure that they are of the correct type (M14-spark plug thread M10 most used one, M18 For heavy engine. 8. Adjust the Gap it necessary by bending the ground electrode (using a spark plug gauge). 9. To clean the plug wash it with a petroleum solvent to Remove oil film. 10. Dry the plug use an Abrasive type cleaner for the best cleaning job. 11. clean the threads with & wire brush 12. Blow out all abrasive particles with compressed air. 13. Use a thin stiff Blade to clean the space between the plug shell and insulator. 14. scrape out all carbon particles turn the plug and dissolve the deposit out. Repeat until the plug is thoroughly clean. 15. Blow out the remaining dirt with compressed air. 16. Widen the plug Gap by bending the Ground (side) electrode so that an ignition point file may be inserted between the electrodes.


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Figure: 17. fill the electrodes until all the carbon is removed and the tip of the central electrode is flat across the top. 18. Adjust the Gap to correct specification. 19. Ensure that the plug seating surface in the head is clean. 20. Install the plug. 21. Tighten the plugs using a Torque wrench to correct specification. (most) 4mm plugs are Tightened to approximately four Kg N. 22. It torque wrench not available, Tighten the plug finger tight. Then using a socket wrench Tighten it approximately halt a turn. 23. Inspect the plug wires. It insulation is brittle. Replace the wire. 24. Clean the distributor cap. 25. Re install the plug wires to the same cylinder from which they were removed.

7. Write down the daily and weekly maintenance schedule o an automobile. Daily Maintenance 1. 2. 3. 4. 5. 6. 7. 8.

Clean vehicle Check engine oil level and top up if necessary Check radiator water level and top up Inspect tyre for normal pressure and ensure that no tyre is fist Check for fuel in tank Check up whether light and electrical accessories are functioning well Check up brake for normal functioning Start engine and check up performance

Weekly Maintenance 1. 2. 3. 4.

Check electrolyte level in battery and add distilled water if necessary Clean battery terminals and apply vasoline to prevent corrosion Check tyre pressure and inflate if necessary to correct pressure Check brake fluid level and top up if necessary


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Fatima Michael College of Engineering & Technology 5. Check tyres for abnormal wear. If abnormal wear is noticed check wheel alignment, chamber etc. 6. Wash vehicle with water mixed with detergent or with soap water. 7. Check oil leak if any from engine, transmission and differential and arrange to rectify. 8. Clean plays and refit if the vehicle is petrol driven 9. Tighten joint belts and axle bolts. 10. Tighten spring and shackle bolts and nuts if necessary 11. Adjust fan belt play if necessary. 12. Check up water pump grease cup and repack, if necessary 13. Check whether Dynamo is functioning well. Adjust regulator if necessary. 14. Check oil in steering box gear box and differential and top up if necessary. 8. Write dour the monthly, quarterly and half yearly maintenance schedule an automobile. Monthly Maintenance 1. 2. 3. 4. 5. 6. 7. 8.

Service vehicle at appropriate data Check up and adjust free ply of brake Check up and adjust free ply of clutch Soap wash vehicle, polish if the vehicle is station wagon. Change engine oil at appropriate mileage. Check up and tune up vehicle (minor) petrol driven Tighten engine gear box and body mounting bolt. Remove all the wheels, check brake drums, brake linings, change brake linings and turns up brake drums if necessary. 9. Examine all wheel bearings for what before refitment. 10. Remove old grease and repack with fresh grease. Quarterly Maintenance 1. 2. 3. 4. 5. 6. 7. 8.

Tighten body bolts and change packing if necessary Blow and adjust brakes Carry out engine tune up if petrol driven vehicle Check up pedals side play and rectify Check up and renew engine counting beds During service, remove and clean shackle pin if necessary. Check up steering linkages and play and adjust if necessary In case of diesel engines overhaul injectors, besides the above items of wash, all the items mentioned in the monthly maintenance schedule should be carried out during quarterly maintenance also.

Half yearly maintenance or fitness certificate work 1. Remove gear box 2. Check differential


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Fatima Michael College of Engineering & Technology 3. 4. 5. 6.

Overhaul all four wheel brakes and the Universal joints Top over haul engine end decarbonizes Over haul carbonator In diesel overhaul injectors and pumps and recalibrate (This should be done by the authorized agencies and preferably in air conditioned rooms). 7. Overhaul water pump 8. Overhaul dynamo and self starter 9. Overhaul exhauster or air compressor 10. Check all wirings and switches 11. Carryout body repairs, including linear work 12. Repaint vehicles, if lorry or van.

9. Explain the various types of records books and form that are being used in automobile service station of cards. Dealer: Place: Data of Sale: SERVICE TYPE Mileage (Kms) Service type Mileage(Kms) Service type Mileage(Kms) Service type Mileage (Kms) Service type S.No. 1

2 3

4

Ro No: Mileage: Kms: 10000

30000

50000

Ro Date: Engine No: Frame No: 70000

110000

130000

150000

170000 190000 210000 230000 250000 270000

290000

310000

330000 350000 370000 390000 410000 430000

450000

470000

490000 510000 530000 550000 570000 590000

610000

630000

CHECK ITEM Basic engine components Engine oil Engine oil filter IGNITION SYSTEM Battery FUEL AND EMISSION CONTROL Pre-filter Water sediment filter Air cleaner filter CHASSIS AND BODY Brake pedal, Parking brake Brake pads and discs Brake lining and Brake drums

90000

CHECK STATUS R R

REMARKS

T R CA C

CA CA CA


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Fatima Michael College of Engineering & Technology Brake line pipes and hoses Brake fluid Clutch Power steering fluid Ball Joints and dust covers Tyres and inflation pressures Lights, horns, wipers Steering wheel linkage and gear box oil Front and rear suspension Tightening of bolts and nuts 5

AC/Cooler Refrigerant C Clean; R Replace; CA Check & Adjust; CR ADDITIONAL JOB: MILEAGE 1,50,000 TIMING BELT Replace Name of the Inspector

CR R CA CR CR CA CA CA CA T NA Check & Replace; T

Tighten

4,50,000 Replace Signature

The status and remarks for all the items mentioned above are indicated on the check sheet during the maintenance operation. Vehicle Regn No:

Job No:

Chassis No:

Date: Table: Road Test Report

S. No. 1 2 3 4 5 6 7 8 9 10 11 12

Parameter to check Front side abnormal noise Rear side abnormal noise Front/rear suspension noise Steering noise Brake caliper noise Misfiring / starting Hunting problems / Stopping problems Underbody noise Abnormal noise from doors/glasses and body operation Overheating of engine AC and Non AC operation Brakes poor / Weak line effective / noisy Wheel bearings noisy

Before work

After work


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Fatima Michael College of Engineering & Technology 13 14 15

Drive shaft noise / vibration Vehicle pulling to one side Poor pick up of vehicle (with AAAC and without AC)

TABLE: TRIP SHEET Name and Address of the Agency

Engaged by Arranged by----------------Vehicle Number-----------------------------

REPORT TO Mr. / Mr.---------------------------------------------------------------------------------------------------------------------------------------No.-------------------

Date:-------------------

Drive Name ----------------------------------------------Closing Time -----------Starting Time------------ Hire Charges TOTAL Time------------ Charge Per km Driver Batta Signature of the Excess Hours Customer Excess Kms Service Tax Permit Charges Advance Rs.-------------TOTAL Driver’s Signature

Rupees

Paise

For Agency

Road Test Report: 1. The road test inspector or the machine makes the road test report after the completion of the maintenance operation. 2. This report contains the vehicle registration number, chassis number; job no, data of test etc. 3. The parameters to be checked included the following:       

Front side and rear side abnormal noise. Steering and brake caliper noise. Misfiring, sudden stoppage of vehicle. Brake condition. Wheel and bearing check. Pick up of the vehicle. Mileage of the vehicle etc.


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Fatima Michael College of Engineering & Technology The road test report gives a fare idea of the condition of the vehicle before and after the maintenance operation. Trip sheet The trip sheet gives the entire details of the vehicle before and after a trip. The starting km and ending km, time of start and closing of the journey time and the charges per km and also the overall cost of trip is described in the trip sheet. Logbook The logbook of a vehicle gives the details of the vehicle, which will be useful not only for the owner of the vehicle but also to the mechanic who might take the job of vehicle maintenance latter. The logbook contains the following details:         

Distance covered Fuel consumption Average fuel consumption Best and worst mileage Total maintenance cost Running costs Faults in the vehicle Likes and dislikes Date of the previous maintenance report

Conclusion: The different statement and records required for the repair and maintenance works were prepared and the uses of records were studied. Vehicle Monthly Maintenance Form (T1) Cooling system Part

Condition

Comments

Radiator Coolant Hoses Water Pump Fan Dashboard warning light Brakes Front Brakes


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Part Master Cylinder Brake Fluid Hoses and brake pipes Brake pedal (any play?) Disks Pads

Condition

Comments

Rear Brakes Part Hand brake Hoses and pipes Shoes

Condition

Comments

Front Lights Part Side light-left Side light-Right Headlight-Left Headlight – Right Full beam – Left Full beam – Right Indicator – Left Indicator – Right

Condition

Comments

Rear Lights Part Tail light – left Tail light – Right Brake light – Left Brake light – Right Indicator – Left Indicator – Right

Condition

Comments

Charging System Part Battery Fluid level Battery Terminals Alternator Fan belt

Condition

Comments


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Fatima Michael College of Engineering & Technology Dashboard light

warning

Ignition System Part HT leads Distributor Cap Rotor Arm Coil Spark Plugs

Condition

Comments

Tires and Wheels Part Front Right Front Left Back Right Back Left Spare Wheel Jack and Lu tool

Condition

Comments

Steering Part Steering fluid Steering wheel play Track rod ends Upper ball joints Lower ball joints Wheel bearings CV Joints

Condition

Comments

Gear Box Part Gearbox unit Transmission fluid – auto Gear Box oil – manual

Condition

Comments


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UNIT –II ENGINE AND ENGINE SUBSYSTEM MAINTENENCE 1. What do you mean by engine overhauling and explain its necessity? Overhauling a machine, strictly speaking, means going over it. When a vehicle engine is being overhauled, it is completely taken apart, every piece is inspected and what ever piece shows appreciable wear is reconditioned to its original shape and dimensions or replaced by a new one. After this the engine is reassembled, put on a test stand, started, tuned up, and carefully tested. Since it is difficult to keep and accurate maintenance log for a vehicle away from the garage sometimes for days or week and since the operators of these vehicles need not be first class mechanics, and because nobody is concerned how efficiently an engine works as long as it runs and pulls the lead, a general overhauling of the engine is done at regular intervals, every 12 or 18 months as the case may be. In general, the methods of overhaul do not differ from maintenance procedure, except that in overhauling a more strict examination is in order as the intervals are considerably greater than in maintenance work, a part even slightly worn, if it is not subject to maintenance inspection periodically, should therefore be either reconditioned or replaced. 2. What is the precaution to be taken before dismantling engine. Dismantling: One of the important rule to be adhered in dismantling an engine is to mark all parts and identify them as the engine is dismantled. It is particularly important to mark camshaft gears and valves if manufacturer’s marks cannot be found. Centre and punch markings will serve the purpose. Changing the tyres around: In order to obtain the greatest mileage from a set of new tyres (including the spare one too) it is necessary to change then round at intervals of about 3000 miles for rear drive vehicles and 2000 miles for front drive vehicles during this useful life. Cuts in tyre treads: Since water and grit penetrate and destroy the cords, small cuts in tyre has to be plugged with readily available “plastic tyre stopping large cuts should be vulcanized at tree. Punctures: When a puncture occurs, on the road, the vehicle should be stopped and the when changed Tube less tyres can be driven to a safe distance even though they puncture, because, they lose their air more slowly. Small punctures can be repaired with rubber patches and rubber solution. Minimum amount of solution is to be applied and it is allowed to dry for 5 to 10 minutes before placing the prepared patch: After this some talc is sprinkled over the patch to prevent sticking to the outer cover major repairs of the tubes are to be done with a professional vulcanizer.


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Fatima Michael College of Engineering & Technology When the vehicle is stored for a long period all the tyres are to be removed and stored an cool dry place, or the vehicle can be jacked off the ground and the tyres can be rubbed with French chalk. 3. Write down the step by step procedure for engine removing and dismantling? Removal of Engine from the vehicle A general procedure for removing the engine from the vehicle can be summed up as follows: (i) (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) (x) (xi)

(xii) (xiii) (xiv) (xv) (xvi) (xvii)

Drain oil from the sump Drain water from radiator and jackets, opening all taps in the cooling system. Remove engine bonnet and where filled vertical side members. Remove radiator Disconnect cable from battery Disconnect fuel fed supply line Remove L.T. cables from ignition system and disconnect wiring to horn. Disconnect radiator hose from the engine side Disconnect oil pipe to instrument pressure gage and thermometer pipe Remove electric horn if liable to obstruct engine removal Take off cable connections to dynamo and starting meter (It is better to remove both starting motor (It is better to remove both starting motor and dynamic if readily accessible, as this allows better access to engine mounting nuts) Remove exhaust pipe flange nuts Take off accelerator and air choke controls Take out all foot boards as far back as rear of gear box Disconnect clutch pedal operating rod and pull of spring. Disconnect foot brake pedal and hand brake, if anchored to engine unit As the engine, clutch, and gear box are built as integral unit an most medium vehicles, it is more convenient to remove the complete unit than gear box; these operations can be performed better on the bench than on the chassis and much time save thereby


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METHOD OF REMOVING ENGINE FROM VEHICLE

At this stage it is advisable to stop and look around the engine unit to make sure that all connections with the chassis frame, dash board, and body work have been released. The final operation will then connecting the front universal joint (just behind the gear box) and the earthing cable or strip between the engine unit and chassis frame, finally removing the nuts of the holdingdown studs or bolts of the engine unit mounting. Usually there are two rubber mountings at the front end of the engine and a single large rear mounting on the gear box.


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Once the engine is freed from the chassis a single or double rope or chain sting should be adjusted carefully round it making sure that the sling comes under the strongest part of the unit and does not foul any of the more vulnerable components like, the ignition unit, oil filter or carburettor. Now locate the chain on the lifting hook of the crane, so that when the engine is raised the front will be on a slightly higher level than the rear. Finally, lift the engine slowly and at the same time push the chassis rearwards so that the clutch housing will clear the cab opening. It is convenient to mount the engine an a suitable engine stand, which will have the following features. (i) (ii) (iii) (iv) (v)

It should take a range of engine sizes Convenient means for securing the engine It should be portable. The frame must be capable of rotation about a horizontal axis. Design of the frame should allow ready access to all engine parts in any position.

CYLINDER HEAD BOLT WRENCH

CAMSHAFT BEARING TOOL

VALVE SPRING COMPRESSOR


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PISTON RING TOOL

OIL SLIMP SCREW DRIVER

3. Explain the Procedure for Decarbonizing the Engine The intervals at which decarbonizing of the engine becomes necessary, depend upon a number of circumstance being governed by the performance and tendency of the engine to knock under acceleration or hill climbing . It is unwise to post pone decarbonising, since increase engine wear will result and the performance will also continue to fall off. The hard carbon deposit found on motor vehicle engine consists partly of carbon from lubricating oil and fuel and partly of hard abrasive siliceous matter carried as fine dust particles by the air of the fuel mixture. The procedure of decarbonising an engine is as follows: (1) (2) (3) (4) (5)

Remove the cylinder head and clean with paraffin Remove the gasket and check for scratches, indentation and other defects. (if necessary use a spare gasket) Clean the cylinder block machined faces with paraffin and dry it so as to prevent adherence of carbon dust. Plug the water circulation orifice in the cylinder block with cotton waste so as to prevent dust entering. Using the starting handle bring a pair of pistons to their top centre position and remove the carbon deposits from their crown with a flat scrapper, leaving a ring of carbon about 1/8” wide around the outer periphery of the crown.

The reason for this is that this carbon which slightly overlaps the edge tends to prevent oil from parsing upwards, tests have shown that the oil consumption in slightly reduced when this carbon ring is left.


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LEVER TYPE VALUE SPRING COMPRESSOR

TOOLS FOR COMPRESSIG OVERHEAD VALVE SPRINGS

BOLT, NUT AND WASHER- PLATE FOR REMOVING VALVE GUIDES (6)Having remove the carbon from the two pistons, right the crank shaft until the next pair of pistons come to top. (7) Wipe the cylinder barrels of the first pair and stuff clean rags or waste in to the top opening, to keep out carbon scrapped from the second pair of piston. (8) Remove the carbon from the second pair as before (9) Continue the above proceeding until all the piston are over (10) Clean the valves and metal around them (11) Scrap the cylinder head off carbon with special scrapper


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Fatima Michael College of Engineering & Technology (12) Remove carbon from the valve ports and metal around the valve guides (13) Remove the carbon deposits in the sparking plug holes with a pointed tool such as a bradawl or scriber. (14) Remove all plugs (with cotton waste) and give the parts a final cleaning with a suitable cloth. (15) Smear each barrel with engine oil and rotate the crankshaft a few times so as to distribute the oil evenly over the surfaces. (16) Replace the gasket, (use a new one if necessary and cylinder head and tighter the holding down nuts on finger tight. (17) Tighten the cylinder head nut in the order prescribed by the manufacturer, using the appropriate torque by a torque wrench. (18) Replace the cylinder head fittings. The above procedure is for, when the engine requires only decarbonising. When a complete over haul is done, decarbonising also takes part as a routine over haul procedure. 4. Explain the procedure for Dismantling an engine? (i) Remove cylinder head (ii) Take off all external accessories, like motor , dynamo ignition unit or injection pump. (iii) Remove engine sump (iv) Rake off timing gear cover, after removing pulleys, etc (v) Remove clutch unit (vi) Take out all valves with their tappets, rocker arms, push rods, etc (vii) Remove connecting rod caps, pistons and connecting rods (viii) Take off timing chain and remove sprockets (ix) Remove crank shaft with flywheel by taking off main bearing caps. (x) Remove camshaft (xi) If necessary, drive out valve guides (xii) Disconnect oil pump drive and remove oil pump at the most convenient stage in the proceeding operations. The oil filter and cleaner are removed early on, also the disstick or oil level gauge.

As the components are removed they should be grouped conveniently on a bench or table, prior to cleaning. Before taking of any component, make sure that it is marked identically with mating part. 5. Briefly mention the methods used for Cleaning the Engine components? If relatively few engines are to be reconditioned at appreciable intervals, the paraffin bath method of cleaning is the most economical. The group of components are immersed in a bath or deep tray containing paraffin and scrubbed with a wire or bristle brush to remove all dirt. INSERTING LINERS: SCREW AND NUT METHOD


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‘BUMA’ TOOL FOR REMOVING CYLINDER LINERS After cleaning the parts are placed in a metal plate or slab to dry in a warm place. The motor garages uses a high pressure spray directly by a nozzle on a flexible hose to the parts which are placed on perforated draining tray; small parts dealt with collectively by placing in a special container. The dirt and grease are quickly dislodged and the paraffin is thoroughly filtered through the detachable filter box before it drains into the reservoir at the bottom, thus there is no need to clean any sludge from the tray or reservoir. Caustic soda made into a solution with hot water, hot saturated, sodium carbonate solutin and trichloro ethelen are other cleansing agents used. 6. Explain the step by step the examination and checking of Components? Often a careful scribing of the various engine parts will reveal indications of damage excessive wear, surface cracks, and other defects without the need for more elaborate inspection. The simple parts such as studs, bolts and nuts should be examined for signs of damage or


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Fatima Michael College of Engineering & Technology stripping. The nuts can be run down the threads as a check. Bolts, nuts and washer faces must be free from edge burrs. The valves, springs , collar’s and retainers, are their examined for wear and shape. The piston should be carefully inspected for surface damage and for wear effects in the ring grooves, on the skirt portion etc. Blackened areas on the land or skirt denotes areas of gas blow- by , and these are noted. The piston crown should be examined for cracks or distortion and the gudgeon pin holes for signs of hammering effect. The big end bearings of the connecting rod and the journals of the crank shaft are inspected for signs of cracking, scoring or other surface defects. The can shaft bearings and journals are also checked. The timing gear teeth will indicate by visual and meshing tests, whether any undue damage or wear has occurred. Similarly the condition of the timing chains rocket teeth are also checked. When spares are available , they can be employed for comparison purpose with the those under inspection. Now the cylinder blocks and head are inspected for the following defects. 1. Cracks in the water jacket walls 2. Damaged machined faces 3. Fractured Flanges 4. Cracked Valve seatings or loose seating inserts 5. Scored cylinder barrels or ridging near the top 6. Loose or damaged cylinder head studs. After the visual inspection the cylinder measurements one taken accurately to find out the wear. The cylinder, piston, piston rings, crankshaft journals, connecting rod bearings, camshaft ,connecting rods, crank shaft, timing gears, chain wheels and chain are all measured for weak. The valve stem, its seating, guide bushes etc: are also to be checked for wear. Worn cylinders can be reconditioned by the following methods. (1) (2) (3) (4) (5)

Machining in the lathe Regrinding in the lathe or with special machines designed specifically for this purpose. Boring with cutters, using a portable machine that can be clamped to the cylinder block. Horning either by portable or fixed machine Reaming with portable or fixed machines

When cylinder liners are used, it is easy to remove the work cylinder lines and insert a new one, and the cylinder reboring can be dispensed with.


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Fatima Michael College of Engineering & Technology (i) Cracks in the piston crown (ii) Burning of crown. (iii) Scored lands and skirt (iv) Blackened areas on land and skirt which are sign of gas leakage from combustion chamber. (v) Oil Scrapper ring hole blockage (vi) Excessive wear of piston lands, skirt, rings grooves and gudgeon pin holes. The other engine components that are to be examined are the various bearings viz, the crank shaft bearings, the camshaft bearings, the connecting rod big end and small end bearings, the crankpin, the connecting rods, the valves, their seatings, guide bushes, the rocker arm, push rods, cam profile, timing gear, chains of chain drive where used, the ignition system of the S.I. engines, the fuel pump and nozzles of C.I. engines etc. After all the engine components are inspected and tested for their measurements, shapes and performance the reassembling of the engine begins.

METHOD OF ADJUSTING VALVE STEM CLEARNACE OF OHV ENGINES


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Fatima Michael College of Engineering & Technology A USEFUL VALVE FACING TOOL 7. What are the special tools and basic instruments required for maintenance? Basic Instruments Needed For Engine: 1. Compression Gauge 2. Vacuum Gauge 3. Tachometer For Ignition System 1. 2. 3. 4.

Power Timing Light Dwell meter Voltmeter Ohm meter

For Electric System 1. 2. 3. 4. 5.

Voltmeter Ammeter (0-30 Amps) Tachometer Hydrometer Batter Load Tester

For Fuel System 1. Fuel pump Pressure Gauge For Emission Checking Exhaust Gas Analyzer For Cooling System Coolant Thermometer 8. What are the common troubles / Faults that normally occur in an automobile? Cooling System Problems and Causes: Engine Overheating


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Fatima Michael College of Engineering & Technology 1. Loss of coolant 2. Defective Thermostat 3. Defective water pump 4. Collapsed Radiator Hose 5. Excessive Rust & Scales 6. Obstructed air passage through Radiator 7. late Ignition timing 8. Combustion leak into cooling system 9. Improper coolant mix 10. Defective Temperature Gauge Engine Runs Too Cool 1. Defective Thermostat 2. Defective Gauge Fuel System Problems and Causes Carburetor flooding 1. 2. 3. 4.

Worn needle and sear Leaky float Excessive fuel pump pressure Improper float adjustment

Rough Idle: 1. 2. 3. 4. 5. 6.

Improper idle Mixture Poor Compression Intake manifold leak Defective spark plug wires Cracked distributor cap Stuck PCV valve

Stumbling During Acceleration 1. Defective accelerator pump 2. Improper adjustment of Acc. Pump 3. Ignition Misfire Sluggish Performance 1. Late Ignition Timing 2. Too rich or too lean mixture 3. Defective advance mechanism


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Ignition system Troubles & causes Engine Misfires at All Speeds 1. 2. 3. 4.

Defective plug wires Cracked distributor cap Fouled spark plug Burned values

Engine Misfires During Acceleration 1. 2. 3. 4. 5. 6. 7.

Defective plug wires Fouled or worn plugs Burned contact points partially shorted ignition coil Open capacitor Poor primary circuit Carburetor Problems

Engine Misfires at high speeds 1. Insufficient Dwell angle 2. Carburetor Problems Hard Starting 1. 2. 3. 4. 5. 6.

Burned contact point Improper ignition timing Low Battery Low Battery Open Capacitor Ignition Timing too much advanced

Starting System Problems & Causes Battery Not holding charge 1. 2. 3. 4. 5.

Internal defect of battery Dirt on Terminals / Loose Terminals Electrical leakage/ shorts Excessive Electrical usage with car stopped / idling Battery not used for long periods.


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Fatima Michael College of Engineering & Technology Battery Always undercharged 1. 2. 3. 4. 5. 6.

Defective alternator / Generator Low voltage regulator setting Infrequent or slow driving with heavy electrical loads Excessive charging circuit resistance Sulphated Battery Too Many Electrical Accessories

Battery Uses Excessive Water 1. High voltage regulator setting 2. Sulphated Battery 3. High temperature Slow Cranking Speed 1. 2. 3. 4. 5.

Excessive starter circuit resistance Dragging starter armature Shorted armature or field Excessive engine friction Worn starter Bushes

Starter Spins without Engaging 1. Defective Bendix drive 2. Dirt or Burr on starter shaft Starter Clicks without Cranking 1. Defective solenoid switch 2. Open starter cable 3. Defective starter Starter Switch or Solenoid Chatter 1. Poor battery connection 2. Defective solenoid 3. Excessive starter circuit resistance No Cranking, No Solenoid Click 1. Defective starter or ignition switch 2. Broken wire, solenoid or switch 3. Defective solenoid or switch Charging System Problems & Causes


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Fatima Michael College of Engineering & Technology No Charge Rate: 1. 2. 3. 4. 5.

Defective alternator /Generator Defective voltage regulator Open or grounded field wire Open circuit Worn or stuck brushes

Low Charge Rate 1. 2. 3. 4. 5. 6.

Regulator out of adjustment Defective regulator Excessive field circuit resistance Defective alternator/ Regulator Worn Brushes Sulfated Battery

High Charge Rate 1. 2. 3. 4. 5.

Regulator out of adjustment Defective regulator Defective Battery High battery temperature An accessory drawing excessive current even when the engine is not running.

Problem: Due to open primary circuit: 1. Burned or oxidized ignition points 2. Ballast Resistor burned or open 3. Ignition points not closing 4. Breaker arm binding on pivot post, preventing closing of points 5. Breaker arm spring weak or broken 6. breaker arm distorted or bent 7. Dirty ignition points 8. Primary lead connection loose 9. Primary winding open 10. Open ignition switch circuit Due to short circuited Primary Circuit Grounded primary coil winding, grounded ignition switch or a lead will cuase excessive current flow and will usually cause wires to burn.


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Fatima Michael College of Engineering & Technology Possible causes for Grounded primary circuit: 1. 2. 3. 4. 5. 6. 7.

Ignition points not opening or closing due to improper adjustment. Ignition points not opening due to worn rubbing, block on Breaker A.R.M Faulty insulating bushing on breaker ARM Cracked or faulty insulator at Distributor, Primary Terminal Grounded condenser. Distributor-To-Coil lead grounded Primary coil winding grounded

Due to Faulty secondary ignition circuit 1. Corroded spark plug cable terminal 2. Cracked insulation on cables (H.T) 3. Ignition so weak or ineffective 4. Moisture on ignition coil , terminals, distributor , 5. Improper type of spark plugs 6. Cracked distributor cap or burned carbon brush in the CAP. 7. Improper connection to spark plugs (not correct as per firing order) 8. Spark plugs damaged, Dirty or wet porcelain cracked or gaps improperly adjusted. 9. Rotor contact spring Bent or Broken 10. Distributor rotor grounded 11. Distributor cap centre terminal broken or missing Due to Battery 1. 2. 3. 4.

Battery run down Terminal loose or badly corroded Improper ground Battery cable undersize.

Due to Excessive fuel supply (flooding) Accumulation of liquid fuel in the intake manifold as well as cylinder. The engine won’t start until, the rich mixture formed by flooding . Reason 1. 2. 3. 4. 5. 6. 7.

Choke not operating properly Automatic choke not properly set Float level set too high Dirty worn or faulty needle valve seat Float sticking or rubbing against side of fuel bowl. Leak in float allowing fuel inside Fuel pump pressure too high


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Due to insufficient fuel supply 1. 2. 3. 4. 5. 6. 7.

Carburetor inlet needle stuck in its seat due to gum in fuel Float level too low Clogged inlet filter at carburetor Faulty or insufficient capacity fuel pump fuel pump strainer clogged Faulty fuel pump Bowl Gasket Fuel line from tank clogged or restricted

When Engine is Hot Hard starting of engine under hot conduction is mainly due to over supply of fuel (flooding) in rare cases an ignition coil may loose its efficiency when it is hot and cause ignition failure. When Engine is cold Apart from the conditions listed under engine won’t start the following conditions are also to be checked. 1. Choke setting too lean 2. Fuel may have kerosene, water or ice 3. Ice in fuel lines 4. Engine is cranked too slowly or won’t turn because: a) Engine oil too thick in sub-zero weather b) Battery too weak due to very low temp 5. Another possibility even though remote is that the water pump is jammed with ice, which will interfere with cranking engine if fan belt is tight. Due to vapour lock Flow of fuel to the mixing chamber is stopped (locked) By the formation of vapourrized fuel pockets or bubbles caused by overheating the fuel by hot fuel pump, hot fuel lines or hot carburetor. High ambient temperature, hard driving defective engine cooling and high altitudes are contributing to vapour lock. After long period of non usage of vehicle 1. More volatile components in the fuel, have evaporated and the remaining ones are not sufficiently volatile to form a combustible mixture. 2. Low or run down battery 3. Corrosion of engine moving parts


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These troubles are more humidity climate and near salt water. Reasons for the stalling of engine 1. Engine idle speed set too low. 2. Large air leakage in take manifold 3. ignition points need attention 4. Vapour lock 5. Over supply of fuel (flooding) 6. Valves set too tight 7. Needle/ seat of carburetor inoperative 8. Contaminated fuel 9. Choke sticking or improperly adjusted 10. Faulty ignition system 11. Spark plugs damp/Dirty or incorrect gap 12. In operative distributor advance 13. Restricted exhaust system 14. Burned, warped or sticking valves 15. Low compression 16. Engine over heating 17. Loose or corroded wire connections 18. Incorrect idle mixture adjustment 19. Incorrect carburetor float setting 20. Leaking EGR valve


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UNIT – III PART – A 1. Draw the carious clutch pedal positions and explain?

2. Draw the clutch release bearing and finger arrangements and explains?

PART – B 1. What is clutch slipping Explain? Maintenance and Servicing of Clutch:


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When a vehicle enters the shop for clutch troubles, one should test – drive the vehicle. While the vehicle is being test – driven, one should check the action of the clutch pedal, listen for unusual noises, and feel for clutch pedal vibrations. There are five types of clutch problems – slipping, grabbing, dragging, abnormal noises, and vibration. It is important to known the symptoms produced by these problems and the parts and the parts that might be the cases. Slipping: Slipping occurs when the driven disc fails to rotate at the same speed as the driving members when the clutch is fully engaged. This condition results whenever the clutch pressure plate fails to hold the disc tight against the face of the flywheel. If clutch slippage is severe, the engine speed will rise rapidly on acceleration, while the vehicle gradually increases in speed. Slight but continuous slippage may go unnoticed until the clutch facings are ruined by excessive temperature caused by friction. Normal wear of the clutch lining causes the free travel of the clutch linkage to decrease, creating the need for adjustment. Improper clutch adjustment can cause slippage by keeping the release bearing in contact with the pressure plate in the released position. Even with your foot off the pedal, the release mechanism will act on the clutch fork and release bearing. Some clutch linkage are designed to allow only enough adjustment to compensate for the lining to wear close to the rivet heads. This prevents damage to the flywheel and pressure plate by the rivets wearing grooves in their smooth surfaces. Other linkages will allow for adjustment after the disc is worn out. when in doubt whether the disc is worn excessively, remove the inspection cover on the clutch housing and visually inspect the disc. Binding linkage prevents the pressure plate from exerting its full pressure against the disc, allowing it to slip. Inspect the release mechanism for rusted, bent, misaligned, sticking, or damaged components. Wiggle the release fork to check for free play. These problems result in slippage. A broken motor mount (engine mount) can cause clutch slippage by allowing the engine to move, binding the clutch linkage. Under load, the engine can lift up in the engine compartment, shifting the clutch linkage and pushing on the release fork. Grease and oil on the disc will also cause slippage. When this occurs, locate and stop and leakage, thoroughly clean the clutch components, and replace the clutch disc. This is the only remedy. If clutch slippage is NOT caused by a problem with the clutch release mechanism, then the


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Fatima Michael College of Engineering & Technology trouble is normally inside the clutch. You have to remove the transmission and clutch components for further inspection. Internal clutch problem, such as weak springs and bent or improperly adjusted release levers, will prevent the pressure plant from applying even pressure. This condition allows the disc to slip. To test the clutch for slippage, set the emergency brake and start the engine. Place the transmission or transaxle in high gear. Then try to drive the vehicle forward by slowly releasing the clutch pedal. A clutch in good condition should lock up and immediately kill the engine. A badly slipping clutch may allow the engine to run, even with the clutch pedal fully released. Partial clutch slippage could let the engine run momentarily before stalling. Note: Never let a clutch slip for more than a second or two. the extreme heat generated by slippage will damage the flywheel and pressure plate faces. 2. Explain clutch Grabbing? Grabbing: A grabbing or chattering clutch will produce a very severe vibration or jerking motion when the vehicle is accelerated from a standstill. Even when the operator slowly releases the clutch pedal, it will seem like the clutch pedal is being pumped rapidly up an down. A loud bang or chattering may be heard, as the vehicle body vibrates. Clutch grabbing and chatter is caused by problems with components inside the clutch housing (friction disc) flywheel, or pressure plate. Other reasons for a grabbing clutch could be due to oil or grease on the disc facings, glazing, or loose disc facings. Broken parts in the clutch, such as broken disc facings, broken facing springs, or a broken pressure plate, will also cause grabbing. There are several things outside of the clutch that will cause a clutch to grab or chatter when it is being engaged. Loose spring shackles or U – bolts, loose transmission mounts, and worn engine mounts are among the items to be checked. If the clutch linkage binds, it may release suddenly to throw the clutch into quick engagement, resulting in a heavy jerk. However, if all these items are checked and found to be in good condition, the trouble is inside the clutch itself and will have to be removed for repair. 3. Explain clutch Dragging? Dragging: A dragging clutch will make the transmission or transaxle grind when trying to engage or shift gears. This condition results when the clutch disc does not completely disengage from the flywheel or pressure plate when the clutch pedal is depressed. As a result, the clutch disc tends to continue turning with the engine and attempts to drive the transmission. The most common cause of a dragging clutch is too much clutch pedal free travel. With excessive free travel, the pressure plate will not fully release when the clutch pedal is pushed to


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Fatima Michael College of Engineering & Technology the floor. Always check the clutch adjustments first. If adjustment of the linkage does not correct the trouble, the problem is in the clutch, which must be removed for repair. On the inside of the clutch housing, you will generally find a warped disc or pressure plate, oil or grease on the friction surface, rusted or damaged transmission input shaft, or improper adjustment of the pressure plate release levers causing the problem. 4. What are the abnormal noises noticed in clutch? Abnormal Noises: Faulty clutch parts can make various noises. When an operator reports that a clutch is making noise, find out when the noise is heard. Does the sound occur when the pedal is moved, when in neutral, when in gear, or when the pedal is held to the floor? This will assist you in determining which parts are producing these noises. An operator reports hearing a scraping, clunking, or squeaking sound when the clutch pedal is moved up or down. This is a good sign of a worn or unlubricated clutch release mechanism. With the engine off, pump the pedal and listen for the sound. Once the source of the sound is located, you should clean, lubricate, or replace the parts as required. Sounds produced from the clutch, when the clutch is initially ENGAGED, are generally due to friction disc problems, such as a worn clutch disc facing, which causes a metal – to – metal grinding sound. A rattling or a knocking sound may be produced by weak or broken clutch disc torsion springs. These sounds indicate problems that require the removal of the transmission and clutch assembly for repair. If clutch noises are noticeable when the clutch is DISENGAGED, the trouble is most likely the clutch release bearing. The bearing is probably either worn, binding, or, in some cases, loses its lubricant. Most clutch release bearings are factory lubricated; however, on some larger trucks and construction equipment, the bearing requires periodic lubrication. A worn pilot bearing may also produce noises when the clutch is disengaged. The worn pilot bearing can let the transmission input shaft and clutch disc vibrate up and down, causing an unusual noise. 5. What is clutch rattles? Clutch Rattles: This condition occurs when engine is idling with transmission in neutral causes are 1. 2. 3. 4.

Excessive clearance at pressure plate driving lags. Anti Rattle springs or retractor spring on release lovers weak, broken or disconnected. Looseness in clutch pedal operating linkages Loose flywheel.

6. What are the causes for noise when clutch pedal is released?


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1. Misalignment of transmission with engine causing slight wobble of clutch disc hub. Noticeable at engine idling or at low speed. 2. Disc hub loose fit on splined clutch shaft. 3. Disc damper springs weak or broken. 4. No pedal play. 5. Weak or Broken pedal return spring. 6. Weak or Broken Release sleeve spring. 7. Clutch linkage sticky 8. Clutch pedal sticky. 9. Clutch release sleeve sticks. 10. Clutch release fork binds. 11. Bad clutch release bearing 12. Loose flywheel.

7. What are the causes for clutch pedal is depressed? 1. Dirty, worn, damaged, broken or inadequately lubricates clutch release bearing. 2. Some conditions as above for clutch shaft rear bearings or crank shaft spigot bearing. Gear Box:


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8. What are the Problems of gear boxes? Slipping of gears at high 1 second gear (3 speed G. Eng) 1. G.B. mounting bolts loose. 2. Control Rods interfere with engine mounts or clutch release lever. 3. Control linkages does not work freely. 4. Gear does not engage fully. 5. Damaged Main shaft spigot bearing. 6. Clutch gear bearing retainer broken or loose. 7. Dirt between G.B. housing and clutch housing. 8. Misalignment of transmission. 9. Worn (or) broken synchronizer assembly. 10. Weak spring in GB cover. Slipping of Gears at low / Reverse Gear


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Fatima Michael College of Engineering & Technology 1. Fist / Reverse Gear Damaged 2. Improperly mated splines of inside of first and reverse gear and / or external splines on second and third synchronizer sleeve. Sticking in gear: 1. Clutch not releasing completely. 2. Low lubricant level. 3. Corroded levers. 4. Tight main driving gear spigot bearing. 5. Defective synchronizer sleeve. 9. What are the troubles with fully synchronized gear boxes? Troubles with fully synchronized gear boxes: When diagonising gear noise note the gear position in which the noise occurs. Noise in all gear position may be due to worn or damaged constant mesh gear box gears or bearing. Noise in only one gear can usually traced to the particular gear involved other causes of noise are: 1. 2. 3. 4. 5.

Misalignment due to loose mounting bolts. Dutch housing misalignment Diat or metal chips in lubricant. Not enough lube oil in G.B. Improper Lubricant.

Noise in all gears: 1. Incorrect lubricant level. 2. Incorrect type of lubricant 3. Counter gear bearing worn or damaged. 4. Counter gear worn on damaged. 5. Clutch gear bearing worn or damaged. 6. Main shaft bearing worn or damaged. 7. Clutch gear worn or damaged. 8. Transmission misalignment or loose. 9. Synchronisors worn or broken. 10. Main shaft gears worn or damaged. Noise in reverse: 1. 2. 3. 4. 5.

Reverse idler gear or shaft worn or damaged. Reverse sliding sear worn or damaged. Shift linkage out of adjustment. Shift linkage bent or damaged. Shift linkage parts loose.


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Fatima Michael College of Engineering & Technology 6. Shift levers, shaft or forks worn. Hard Shifting: 1. 2. 3. 4. 5. 6. 7. 8.

Clutch pedal free travel incorrect. Clutch parts are worn or damaged. Shift linkages out of adjustment. Shift linkages bend or damaged. Shift linkage parts loose. Shift levers shaft or fork worn. Incorrect types of lubricant. Incorrect level of lubricant.

Jumps out of Gear: 1. Shift linkages out of adjustment. 2. Shift linkages bend or damaged. 3. Shift linkage parts loose. 4. Shift levers shaft or fork worn. 5. Shift cover loose or gasket damaged. 6. Transmission misalignment or loose. 7. Synchronizer worn or broken. 8. Clutch gear bearing retainer broken. 9. Clutch gear bearing worn or damaged. 10. Clutch spigot bearing worn or damaged. 11. Main shaft worn or damaged. 12. Main shaft bearing worn or damaged. 10. Explain the various problems encountered in a propeller shaft? Usually the problems that arise in propeller shafts are noise and vibrations which are the result of incorrect universal joint angles, unbalanced parts or loose or worn parts. They may also arise due to damaged propeller shaft tabes or material such as under coating stioking to the tube to cause unbalance. Checks: The following checks should be made after a through visual inspection. Such an inspection gives many dues like damages to the shaft tube, loose joints etc. 1. Chech the universal joint angle 2. Chech the propeller shaft run out Run out near the joint should be less than 0.01 inches. Run out in the centre of shaft should be less than 0.015 in. A bent propeller shaft results due to accident which should be replaced.


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Check the shaft for unbalance. It may be done in a garage. 3. Check looseness of all joints / parts. 4. Check every 600 miles that the four bolts holding the propeller shaft to the rear axle are tight. Servicing: The propeller shaft and universal joint servicing should be done periodically proper cleaning and greasing of joints should be done carefully. In case the universal joints are fitted with grease nipples – grease then every 3000 miles. 11. Write down the Trouble shooting of a propeller shaft? Trouble 1. Vibration and Noise

Cause a. Brken or worn bearing of universal joint spider. b. Distorted propeller shaft. c. Unbalanced propeller shaft d. Loose propeller shaft

2. Noise occurring at a. Worn or damaged universal joint. standing. Start or during b. Worn propeller shaft position. casting. c. Loose propeller shaft. d. Loose flanged xohe of universal joint.

Remedy Replace Replace Replace Retighten Replace Replace Retighten Retighten

12. Explain the rear axle problems? Noise when polling straight ahead: 1. 2. 3. 4. 5. 6. 7. 8.

Not enough oil. Wrong grade of oil. Poor quality of oil. Excessive Backlash in crown wheel and pinion. Crown wheel (Ring Gears) and pinion worn. Pinion shaft Bearings worn of cease. Excessive end play for pinion shaft. Crown wheel and pinion misalignment due to bent axle housing or distorted differential case. 9. Ring gear (crown wheel) warped. 10. Differential bearings worn or loose. 11. Ring gear rivets or screws loose. 12. Non matching ring gear and pinion. Knocking or clicking: 1. Flat spot on ring gear or pinion tooth or tooth chipped or metal lodged on tooth.


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Fatima Michael College of Engineering & Technology 2. 3. 4. 5.

Flat spot on bearings. Loose axle shaft keys. Loose splined shafts Mismatched differential case halves.

Intermittent noise: 1. Warped Ring Gear. 2. Loose Ring Gear Rivets or Screws. 3. Ring Gear improperly installed on differential case due to dirt or Burs between the two. Noise on turns: 1. Differential planet gears or sun gears chipped broken or scuffed. 2. Planet gears (differential) Binding on pinion shaft. 3. Differential gears (planet or sun) Become loose due to worn usefulness though wean bushing or shaft. 4. Excessive backlash between differential gears. 5. Excessive Axle shaft and play. 6. Contact surfaces between differential sun gears and case burred. Scored or damaged. Vibrations: 1. 2. 3. 4. 5. 6. 7.

Rough rear wheel bearing Unbalanced or damaged propeller shafts. Type unbalances. Worn universal joint in propeller shaft. Incorrect drive line angle. Improperly indexed propeller shaft at companion flange. Companion flange run out too much.

Oil leakage at axle ends: 1. 2. 3. 4. 5. 6.

Oil level too high. Oil too light or poor quality. Axle shaft oil seals worn. Axle shaft bearing retainer loose Cracked Reoa Axle housing. Vent (if provided) clogged.

13. What are the reasons for hard steering? 1. Low or uneven type pressure. 2. Steering gear or connections adjusted too tight. 3. Insufficient or incorrect lubricant used.


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Fatima Michael College of Engineering & Technology 4. Excessive castor. 5. Suspension arms bent or twisted. 6. Front spring sagged. 7. Frame bent or broken. 8. Steering knuckle bent. 9. Kingpin frozen in bushing. 10. Excessive misalignment or steering shaft coupling. 11. Misalignment or steering column and gear. 14. What are the causes for excessive play or looseness of steering? 1. Gear connections adjusted loose or worn. 2. Steering knuckle bushing worn. 3. Front wheel bearing improperly adjusted or worn. 4. Worn Ball joints. 5. Worn or loose steering shaft bearings. 6. Worn control arm bushing. 7. Steering wheel loose on shaft. 8. Loose linkage. 9. Excessive backlash. 10. Worn intermediate rod or tie – rod 6ockets. 15. What are the reasons for poor returability? 1. 2. 3. 4.

Front End Need Lubrication. Too Tight adjustment of steering Gear. Front End Alignment of steering Gear. Misalignment of steering gear to column.

Rattle or chuckle in steering gear: 1. 2. 3. 4.

Insufficient or incorrect lubricant. Excessive Back lash Worn or loose shaft bearing. Pitman Arm or Drop Arm Loose on shaft.

16. What are the causes for erratic steering on application of brakes? 1. Oil or brake fluid on lining. 2. Improperly adjusted brakes. 3. Weak spring at front 4. Low or uneven tyre pressure. 5. Insufficient or uneven castor. 6. Bent steering knuckle. 7. Shift linkages out of adjustment. 8. Shift linkages bend or damaged.


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Fatima Michael College of Engineering & Technology 9. Shift linkage parts loose. 10. Shift levers shaft or fork worn. 17. What are the reasons of vehicle pulls to one side? 1. Low or uneven tyre pressure. 2. Incorrect or uneven castor or camber. 3. Improperly adjusted wheel bearings. 4. Uneven front height of vehicle. 5. Incorrect Toe – in. 6. Oil or brake fluid inclining. 7. Unevenly adjusted Brakes. 8. France Bent or Broken. 9. Rear wheels not cracking front wheels. 10. Loose u – bolts or sheared centre bolt of rear springs. 11. Broken or weak rear springs. 18. What is steering wandering? Tendency of a can to veer away from a st Para without driver control frequency steering movement is necessary. Low or uneven tyre pressure. Normal drng: Lack of tracking means the run with are not following a page When braking: When the brake shoes are unevenly adjusted or when a stucn w cylinder or caliper piston cases the shoes at one w to apply less broking 19. What is steering kick back? Steering shock – consist of sharp of rapid movement of the steering w that occur when the front w encounter obstruction in the road, incurred tyre inflation. Noises: Rating (connected with suspension system. 20. What are the reasons for long pedal travel or pedal goes up to floor level? S.No 1 2 3 4 5

Causes Excessive clearance between linings and drum Weak hose. (Bulging the hose) Leaking wheel cylinders. Leaking in master cylinders Leaking stop light switch.

Remedy Adjust brakes Replace with new Service with repair kit Service with repair kit Replace


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Fatima Michael College of Engineering & Technology 6 7 8 9

Air in hydraulic system. [ Farest wheel cylinder] Blocked master cylinder cap end hole. Low fluid level in master cylinder Wear of brake pedal bush

Bleed the system. Clean or replace Clean or replace Replace.

21. What are the reasons for spongy pedal and write down the remedies. S.No. 1 2 3 4 5 6 7 8 9

Causes Air in hydraulic system Improper lining excessive between lining and shoe Distorted shoes. Bell mouthed, worn out, weak or cracked drums Clogged master cylinder, filter cap, vent hole Weak hose Weak cylinder (master) mounting. Bent master cylinder push rod and clevis bent Unbedded linings (lining not in full contact)

Remedy Bleed Reline Replace Replace the drum Clean or replace and bleed Replace Check and strength master ness cylinder A place push rod and dews Bed linings.

Brakes pulling (vehicle pulls to one side)

S.No 1. 2.

Causes Uneven adjustment of brake Tyres improperly inflated.

3.

Tyre tread unevenly worn on either side or different Grease fund soahed living on brake opposite to the direction of pulling. Linings of difference grades an either side of brake Unbedded linings Shoes wrongly fitted Rivers loose in lining Wheel cylinder pistons seized Wheel cylinder diameter different on opposite side Clogged on restriction in hydraulix Clean and replace pipe line hose or pipe Weak a broken shoe return springs Check and replace weak open coiled or checked springs Drums oval or eccentric True up or replace

4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Remedy Adjust all the brakes evenly. Inflated to recomerenced for feelence with recommended grade of lining all Replace with recommended grade of lining all Replace lining after remedying the causes of grease or thick leak Replace with recommended grade at linings all rounds Bed linings Install loading and traviling shoes correctly. River properly Service or replace wheel cylinder. Replace with correct cylinder.


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Fatima Michael College of Engineering & Technology 14.

15. 16. 17. 18. 19.

Loose back plate mounting bolbs, loose Tighten back plate mounting bolts and shoe abutment or adjuster housings adjuster housing mountings. If abutment is loose replace back plate. Improper steering Geometry Reset Loose or worn tie rod end Tightener replace Loose king pin and bushes Replace as a set Loose wheel bearing, steering or a Adjust or tighten clamp nuts Weak shock absorber Replace

22. What are the causes and remedies of Brake fade? Brake fade: Fade is a temporary reduction of brake effectiveness resulting from heat. 1. Incorrect grade of lining 2. Distorted shoe 3. Overload vehicle 4. Drafting brakes 5. Thin drums 6. Contaminated third 23. What are the causes and remedies for 1. 2.

3.

4. 5. 6. 7. 8. 9. 10. 11. 12.

Back plate bend or slightly twisted Metallic parts (or) embedded in lining

Replace with proper grade Replace Reduce reload Adjust (or) rectify the problem Replace Orange the fluid

shoes Replace parts

dust Band paper the lining and drum and remove metal particles if any (or) replace timings down if necessary. Loose rivers (or) linings not Reline shoe properly hold evently against shoe rim/gab bet lining & shoe rim) Drum not true, weak (or) True up (or) replace drums. distorded Incorrect grade of lining Replace lining with recommended lining. Shoe scrapping on back plate Lubricate shoe pads with high shoe pad melting point graphite grease Weak (or) Broken hold down Replace defective parts spring Loose wheel bearing Adjust bearing Loose back plate (or) wheel Tighten cylinder Over adjusted steady post Adjust properly Glazed lining Surface lining with sand paper Highly polished drum Skim down


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24. What are the causes and remedies for when Braking? Shapping noise in the front end: 1. 2. 3. 4.

1. 2. 3.

Deep grooves in back plate shoe Replace back plate pads Lack of lubricate in moving parts Lubricate all moving parts on the back plate with high melting point Loose drum (or) back plate Graphite greasts tighten Loose (or) worn out front end Tighten (or) replace defective parts. parts m ) thumping

Loose back place, drum (or) axle Tighten is bolts Grabbing lining Replce with recommended grade of lining Shoe releasing spring unequal Replace spring wear uneven brake drum inner Shim the down (or) wep tera diameter

25. What are the causes and remedies for Grinding noise in braking? 1. 2. 3. 4. 5. 6. 7.

Shoe vim foaling with the drum Weak shoe hold down spring (or) bent pint Bent shoe web Foreign material in lining Worn out (or) broken lining

Check shoe retracting springs for correct fit Replace parts

Replace shoe Remove & replace lining Repalce with lining kib, skim (or) replace Rough drum surface Drum it scorced skim drum Improper adjustment of steady Adjust properly. past Body Maintenance:


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26. Explain the procedure for servicing the wheel cylinder of braks? Remove the brake down Remove the brake shoe pull back spring Disconnect the brake line or hose form the wheel cylinder Tope the end of the line to prevent entrance of dirt Remove the wheel cylinder retaining belt and lift the wheel cylinder free Remove the links and rubber boot from the cylinder Remove the pistons , cups, expanders and springs Wash all metal parts in alcohol or brake flushing fluid Blow out all passages with compressed air Inspect the cups for swelling or distortion , if the cups are swellen, contamination of brake fluid may be suspected and entire hydraulic system should be flushed Inspect the wheel cylinder bores for scratcher, scoring etc of light scratcher are found honing may be done to remove them else wheel cylinder has to be replaced. Check the fit of the pistons in the cylinder bore. Replace the cylinder if the clearance is not within the specified limits Lubricate the bore with approved brake fluid Install all the other components with the wheel cylinder and fin it on the wheel. Bleed the system to remove air. 27. What are the causes and remedies for Brake Binding? 1. 2. 3. 4.

Pedal does not return fully

Lubricate (or) recondition pedal shaft & bushers. No clearance but push rod Adjust brake pedal free play and master cylinder piston Improperly adjusted service Check & adjust brake (or) hand brake Recuperating and feed port Service master cylinder


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5. 6. 7. 8. 9.

clogged in master cylinder Swollen seals

Flush the system and replace all rubber parts Seized wheel cylinder piston Cylinder services (or) replace wheel cylinder Improper Brake fluid Replace Weak (or) Broken shoe Replace return spring Blocked filler cap and hole Clean (or) replace the cap.

28. What are the causes and remedies for one wheel drag? 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Weak or broken retracting springs Clearance between shoe & drum to a small in a wheel Loose wheel bearing Wheel cylinder cup seals swollen & piston seized Excessive ovality of drum Obstructed hydraulic Distorted shoes Incorrect grade of lining Draging of Rear brake Mal adjustment Parting Brake cable seized

Replace the springs Adjust Adjust Service with kit True the drum clean and flush Replace shoes Replace with proper linins Adjust Lubricate & adjust

29. What are the causes and remedies for hard pedal or poor braking? 1. 2. 3. 4. 5. 6. 7. 8. 9.

Causes Incorrect linning Grease or oil soaked lining Un bedded living Glazed lining Pedal binding on the shaft Seized master cylinder wheel cylinder discon Wrongly fitted shoes

Remedy Adjust properly Replace Bed lining properly Sand paper the lining surface Lubricate (or) condition or Service with kit.

Install leading & trailing shoes correctly Bell mouthed barrel shaped Replace (or) reborb the down. (or) polished drum

30. What are the causes and remedies for reduced brake pedal travel? S.No 1.

Causes Master cylinder hole blocked

Remedy recrepeting Service the master cylinder


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Fatima Michael College of Engineering & Technology 2.

Swollen cup seal in master Flash the system and replace cylinder all insber pads. 3. Weak shoes retracting spring Service & replace inserted part 4. Wheel cylinder Replace the spring 5. Lining swelling Replace lining. 31. What are the causes and remedies for Judden in brake pedal? 1. 2. 3. 4.

Excessive ovality of drum Loose drum on hub Worn (or) loose bearing Rusty drum

True the drum Tighten Replace or adjust De rust (or) replace

Batteries which are not too badly sulphate may often be reconditioned by charging at a 1 1 very low rate from to their normal charging current. The charging should be continued until 5 10 1 the battery begins to gas freely when it should be discharged through high resistance at about to 3 1 ampere note. 4 Other battery troubles which may occur are internal short circuiting of the plates due to the breaking away of the paste from the plates and its lodgment between the plates and buckled plots due to excessive vibration or constant overcharging. For charging the battery the instructions of the manufacturer are to be strictly followed. A 1 battery in good condition can be given a rapid or boost charge such that it is charged in to 1 d hour . The acid temperature should not exceed 110 F during this, process. For the regular maintenance of the battery the following equipments instruments and materials and required. i) ii) iii) iv) v) vi) vii)

Battery charger Hydrometer Voltmeter with loading resistors Distilled water Acid solution (H2SO4) Terminal cleanser Wiping cloth etc

Maintenance of the vehicle tyres: Automobile types are costly items and are subjected to rapid wear maintained properly periodic inspection for the correct inflation pressure, wheel alignment, toe-in, camber, etc, will prolong the life of the tyre.


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For removing a tyre with tube, the tube is first deflated and then both the beads are pushed off then rim seatings with a tyre lever. The bead on the valve side should be first loosened with a tyre lever and pushed in to the rim well on the opposite side of the wheel to the valve. Using a second tyre lever, about 2” away from the first the bead should be prised over the rim and then the rest of the bead will readily come over the rim. When a tube is inserted into its cover, it should be slightly inflated before attempting to replace the tyre bead in position. Excessive or irregular tyre wear can be due to several different causes which includes. (i) (ii) (iii) (iv) (v) (vi) (vii)

In correct inflation pressure Wrong steering mechanism geometry Incorrect camber, castor and toe-in Bad driving of the car Unbalanced wheel and tyre Worn stearing mechanism and king pins. Impact of tyre against hard objects.

The tyre inflation pressure depends upon the size of the tyre, the load on the tyres and the maximum speed at which the vehicle is driven.


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Some causes of excessive tyre wear (a) Under inflation (b) Over inflation (c) Excessive camber (d) Excessive toe-in If the tyre pressure is much lower than the correct value, then the type walls will flux more and greater stress will occur on the type cords, causing, greater heat to on the weaken the casing . The result will be uneven wear on the read, reduced vehicle performance, greater roll on curves and higher fuel consumption. There will be greater tread contact area with the ground. The higher inflation pressure causes greater tyre chord stresses and increased wear on the centre of the tread. It also tends to reduce the further over inflated tyre is more susceptible to cuts and brusises. Excessive wheel camber will cause greater wear on the outer ribs of the tyre. For excessive negative camber the inside tyre ribs will wear more. If the toe-in is greater than the correct distance given by the manufacturer, then the front wheel tyre will develop fins on the outside edges which will shorten the tyre life. If the front wheel have too much toe-out the tread ribs will shown fins, but on the opposite sides of the ribs. If a car with correct camber angle is regularly driven on a well cambered road the left hand front tyre will tend to wear more than the other tyres.

Severe acceleration, breaking, steering action and springing movements will cause irregular spotty wear on the front tyres as if they were tonehed in places with high speed grinding wheel. When a vehicle wheel, driven at moderate speed strikes the side of a road kerb or any other


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Fatima Michael College of Engineering & Technology solid object the impact will often fracture the tyre casing chood, with the result of a later tyre fail by blow ow. If the wheel unit is out of balance, road shocks of a vibratory kind known as tramp and steering shimmy may occur. The forms is due to wheel unbalance in the radial sence and the latter due to unbalanced region out of centre.

When the complete tyre and wheel is tested for balance, the lighten side of the wheel is revealed and the correct balance is effected by placing lead weights specially designed for the purpose, on the rims lighter side. The rate of tread wear increases fairly rapidly with the vehicle speed. The following figures by the Dunlop Rubber company emphasigs this Average speed 30 m.p.h 40 m.p.h 50 m.p.h 60 m.p.h 70 m.p.h

Mileage obtained Normal 76% of normal 59% of normal 43% of normal 30% of normal

Other factors affecting tyre wear include condition of road surface, road curves and graduals, and temperature. The rate of wear on warm, roader is twice to that if cold roads.


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Method of sealing small punctures of tubeless tyres with rubber sealing plug.

Method of changing tyres around to obtain maximum mileages

Method of adjusting valve stem clearance of OHV Engines


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A useful valve facing tool

Figure: Mechanic toe gauge used to measure the distance between the centres at the front and back of the tires. The difference is distances is the total toe (Mutsubishi Motor Sales of America. Inc) Of frame bracket. When the shims are inside the frame bracket (Figure) adding shims moves the upper control arm inward. This reduces positive camber. When the shims are outside the frame bracket, adding shims moves the upper control arm outward. This increases positive camber. Adding shims at one bolts and removing from the other moves the outer end of the uppercontrol arm forward or backward. This increases or decreases caster figure: Note: Some trucks have an I-beam front axle and leaf springs (figure) instead of upper and lower control arms. Caster is adjusted by installing tapered caster shims between the spring and the axle. If the shims are installed backward, the axle will have excessive negative caster. The drive may complain of difficulty in keeping the truck in a straight-ahead position, wander and pull. 2. Cam-Bolt Adjustment Figure shows one arrangement using offset or eccentric cam bolts to adjust caster and camber. The two bushings at the inner end of the upper control arm attach to the frame brackets with two cam bolts. Tuning the cam bolts the same amount in the same direction changes camber.


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Figure: Caster and camber adjustments on some vehicles using shims (Chevolet Division of General Motors Corporation). Turning only one cam bolt or turning both cam bolts in opposite direction changes caster. On some vehicles , the cam bolts are in the inner ends of the lower-control arms.

Figure: Caster and camber adjustments by turning offset, or eccentric, cam bolts (ATW) 3. Pivot-Shaft Adjustment This arrangement has slots in the frame at the two points where the upper control-arm pivot shaft attaches bolts and moving the pivot shaft in or out changes camber. Moving only one end changes caster. 4.Struct-Rod Adjustment Changing the length of the suspension strut rod changes caster . Turning the cam bolt on the inner end of the lower control arm changes camber.


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Fatima Michael College of Engineering & Technology Caster and Camber Adjustments (Strut suspension). Many vehicles with MacPherson struts do not have camber and caster adjustments. Other have a cam bolt at the lower end of the adjust camber.(Figure). Turning the cam bolt moves the top of the wheel in or out. If no camber adjustment is provided, some manufacturers recommend enlarging the bolts holes in the bottom of the strut. On some MacPherson strut Suspensions, caster and camber are adjusted at the upper strunt mount (figure) Moving the strut toward the front or rear changes caster. Moving the strut in or out changes camber.

Figure: Adjusting caster and camber by shifting the position of the pivot shaft, using slots in the frame. (Chrysler Corporation) Toe Adjustment: After making caste rand camber adjustments, check and adjust toe. Front wheel toe is measured with the steering wheel centered and the wheels straight ahead. Figure shows a mechanical too gauge that measures total toe. Its length is adjusted so the pointers are at the centers of the tires. The total toe is the difference in distance between tire centers at the rear and at the front. To adjust toe, loosen the tie-rod locknuts (figure) Rotate the rods until the toe measurement is set to specifications. Do not allow the boots on the ends of the steering gear to twist while making the adjustment. Then tighten the tie –rod locknuts to the specified torque. Steering- Wheel Centering When all four wheels are properly aligned and there is not thrust angle, the steering wheel will be centered while the vehicle is moving straight ahead (figure). If not, the steering wheel can be centered by adjusting the tie rods. Adjust the tie rods to steer the front wheel in the same


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Fatima Michael College of Engineering & Technology direction the steering wheel is off center. For example, if the steering wheel is off center to the right, adjust the tie rods to make the front wheels steer toward the right.

To make the adjustment, loosen the locknuts and turn both tie rods the same amount in the same direction. (Figure). On one car, only 1/5 turn of the tie rods moves the steering-wheel rim 0.250 inch [6 mm] or 2 degrees.

Caster Adjustment slide the upper plate toward the front of car until the desired caster reading is obtained. Camber Adjustment slide the Large Lock nut toward or away from the Engine until the desired camber reading is obtained. Figure: Adjusting caster and camber on a MacPherson strut by repositioning the upper strut mount (Moog. Automotive, Inc).


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Figure: Adjusting to by changing the length of tie rod (Chrysler Corporation).

Figure: Tie rod adjustments to center the stering wheel (Chrysler Corporation). Rear-Wheel Alignment: Many front-wheel drive vehicles have stub axles or spindles on which the rear hubs and wheels mount. Rear wheel camber and too may be adjustable. Rear-wheel caster is usually set to zero and is not adjustable. Rear-wheel caster is usually set to zero and is not adjustable. Various methods of adjusting rear-wheel camber and toe are described below. Refer to the vehicle service manual for rear-wheel alignment procedures on specific vehicles.

1. Adjusting Rear-Wheel Camber in some vehicles, camber is adjusted by turning a cam bolt in the inner end of the lower-control arm or spindle-support rod. On other vehicle, shims placed between the spindle and the mounting plate provide the camber adjustment.


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Figure: Adjusting rear-wheel camber by turning a cam bolt in the inner end of the lowercontrol arm, or spindle support rod. (Chevrolet Division of motors Corporation).

Figure: Using shims to adjust rear-wheel camber and toe, adjustments at the left-rear wheel are shown. (Chrysler Corporation).

(a)

Adjusting control arm postion


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Figure: Adjusting rear wheel toe by (A) adjusting control arm position and (B) shimming the trailing arms. (Buick Division of General Motors Corporation, Dana Corporation)


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UNIT – IV PART – A 1. Explain the importance and various features of battery maintenance. Maintenance of the vehicle battery Most of the vehicles use the lead-acid battery using separate packs of positive and negative plates immersed in a solution of sulphuric acid. The battery must be properly maintained at all times, since any failure of it will put the vehicle out of action. The various maintenance item for a typical battery are illustrated in the figure. The electrolyte solution of the battery is mark by adding gradually 1 volume of commercial sulphuric acid of 1.835 density to 3 volumes of distilled water to give a final cool solution of check 1.28 to 1.29 density of the electrolyte at fully-charged, half charged and completely, discharged conditions are 1.28 to 1.29, 1.19 to 1.21 and 1.11 to 1.13 respy: all at 80o F. The acid density is frequently checked with a hydrometer, which consists of an outer glove tube, with a rubber to dip into the acid and an inner calibrated glass float to read the acid density. Lower reading from any one cell of the battery indicates a faulty cell. The acid level is to be kept just above the top of the plates. If the level drop through evaporation as in hot weather or through are charging, distilled water n to be used to bring up the acid level. However if the level falls during charging when the acid is splashed out due to gassing, or the acid accidentally spilt, fresh acid solution is to be used. When the vehicle is in used, the battery should be checked and of necessary topped-up every month or so.

2. Draw the cut section view-of a battery and the maintenance activities or each component.


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Figure: Voltage of the battery measured across its terminals cannot indicate the condition of the battery, under a special form of voltmeter which apphes an electric load by means of shunting resistance which taken a heavy current discharge for a short time is used. A fully charged battery cell should read 215 to 2.2 volts otherwise it is defective. The battery should never be left in a semi-or fully discharged condition for long. It is advisable to give the battery an occasional charge when the car is not used. Of the vehicle is to be laid up for a long period, the battery can be stored by the dry method. To do this the battery is first fully charged and then the electrolyte drained out. The pitch seal is removed with the aid of a hot iron and the wooden separators taken out, dried and stored in a dry place. The battery plates are also dried. When the battery is again required, it is reassembled, filled with electrolyte and charged. Every twelve months when in normal use, empty out the electrolyte, wash out the sediments from the sediment wells with distilled water and refill with fresh electrolyte and charge. The battery terminates must be kept clean from the corroded products, otherwise it will act as a insulator. For this terminals can be coated with Vaseline or thick grease. A white deposit formed on the plates in an indication of the neglect of the battery. This is due to sulphation, lead sulphate being formed.

Batteries which are not too badly sulphated may often be reconditioned by charging at a 1 1 to very low rate from . Their normal charging current. The charging should be continued 5 10 until the battery begins to gas freely when it should be discharged through high resistance at 1 1 about to ampere rate. 3 4


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Fatima Michael College of Engineering & Technology Other battery troubles which may occur are internal short circuiting of the plates due to the breaking away of the paste from the plates and its lodgement between the plates and buckled plates due to excessive vibration or constant overchanging. For charging the battery the instructions of the manufacturer are to be strictly followed. A 1 battery in good condition can be given a rapid or boost charge such that it in charged in to 1 2 hour. The acid temperature should not exceed 110o F during this process. 3. What are the equipment required for battery maintenance. For the regular maintenance of the battery the following equipments, instruments and materials are required. (i) (ii) (iii) (iv) (v) (vi) (vii)

Battery charger Hydrometer Voltmeter with loading resistors Distilled water Acid solution (H2SO4) Terminal cleanser Wiping cloth etc.

4. What are the causes for self state starter not tuning up? Explain briefly. If the lights become dim or go our when the starter switch is closed, the battery maybe too weak to operate the starter. In this case a push start is needed. Cars equipped with alternators cannot be push started if the battery is complete dead because alternators retain no residual magnetism. Due to starter circuit 1. Low battery 2. Connections loose, dirty, corroded or broken at battery terminals, starter switch terminal or battery ground strap. 3. Short circuit across starter terminals. 4. Neutral start switch out of adjustment or defective. Due to starter switch 1. 2. 3. 4. 5.

Starter switch stuck Defective solenoid starter switch makes poor contact due to dirt, corrosion, bent parts or weak spring Starter switch fails to close circuit because of sticking or broken contact part Neutral safety switch out of adjustment or defective.


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Fatima Michael College of Engineering & Technology Due to armature and field circuits 1. 2. 3. 4. 5.

Armature winding burned out, shorted, grounded or open circuited. Field coils burned out, shorted or grounded. Broken wire in armature winding or brush pigtail lead Broken wire in field winding or broken lead Loose dirty or corroded connections in field circuit.

Due to commutator and brushes 1. Brush pigtail leads loose or broken 2. Starter brushes cracked crosswise 3. Arm type brush holder sticks 4. Brush sticks in sliding brush holder 5. Bent brush holder causes poor contact 6. Starter brushes worn badly 7. Brush leads shorted or have loose, dirty, broken or corroded connections 8. Poor brush contact due to weak or broken springs 9. Brushes coated with oil 10. High (Raised) Mica between commutator serviced prevents brush contact. 11. Commutator bars loose and or solder melted. 12. Commutator dirty, corroded or broken Due to engine resistance 1. 2. 3. 4. 5. 6. 7.

Piston sticking to cylinders in overheated engine Piston stuck to cylinders due to gummy oil Jamned generator armature Combustion chamber full of water Sold ICE in water pump Broken engine moving parts Due to cold weather and too heavy oil

Due to armature binding 1. Loose field poles 2. Armature shaft frozen in bearings 3. Loose end plates 4. Windings thrown out of armature slots 5. Armature locked magnetically to field poles because of loose bearing or worn / beat shaft 6. Bendix spring retaining screen loose and jammed against housing 7. Cracked/Distorted drive housing 8. Starter misaligned 9. Jamming due to burredteeth on pinion / Ring gear 10. Starter pinion (sliding gear type) Jams due to incorrect endwise clearance.


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5. What are the reasons for high engine oh consumption. 1. External oil leaks 2. Leaky piston rings (Due to wear) 3. Leaky piston rings (Due to sticking caused by gummy Deposits. Free the rings with suitable solvent). Blue smoke indicate badly leaking rings. 4. Worn piston and cylinders 5. Cylinder block distorted by Tightening cylinder head bolts unevenly. 6. Excessive clearance between valve stems and guides. 7. Worn main bearing / conrod bearing. 8. Oil pressure too high (wrong setting of oil pressure relief valve or clogged relief passage) 9. Loose piston pins 10. Grade or oil too light (Hard driving on hot day will also consume more oil) 11. Clogged crank case ventilation system 12. Intake manifold leak together with valve door gasket leak 13. Oil level too high 14. Piston ring gaps not staggered 15. Incorrect ring size 16. Piston rings out of round broken or scrod 17. Ring lands damaged 18. Ring grooves damaged and rings struck in ring grooves.

6. What are the reasons for frequent changing of a battery? Battery requires frequent charging Insufficient current flow to battery 1. Defective generator / Alternator 2. Incorrect Voltage regulator setting 3. Regulator contacts oxidized or burned 4. Sulphated battery 5. Corroded battery terminal 6. Regulator not grounded 7. Slipping fan belt, 8. Loose connections/Grounds in lighting or ignition circuits 9. Blown regulator fuse 10. Wrong size generator drive pulley 11. Shorted or open alternator rectifiers 12. Grounded stator wire in alternator. 7. What are the reason excessive starting load causing abnormal current flow from battery.


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Fatima Michael College of Engineering & Technology 1. 2. 3. 4. 5. 6. 7.

Frequent use of starter motor. Excessive use of starter motor (difficult starting) Faulty starter motor Excessive engine friction Excessive lighting loads Abnormal accessory loads Internal Discharge of battery

8. Write down the steps involved in servicing the ignition system with contact points. 1. Clean, Regap or replace spark plugs 2. Clean and inspect the ignition coil if the tower (TOP) is cracked replace the coil 3. Replace the primary wire (coil to treasure 4. Clean and inspect the distributor cap 5. Examine the rotor 6. Twiss the distributor seat in are of rotation and reliable it mechanical must be repaires. 7. Inspect the contact points replace then is necessary, check and set the cap. 8. Put a small amount of 9. Check and set the dwell using dwellmete 9. List out the causes for the ignition system troubles and causes. Engine misfire at all speed 1. 2. 3. 4.

Defective plug wires Cracked distributor CAP. Fouled spark plug Burned valves

Engine Misfires during acceleration 1. 2. 3. 4. 5. 6. 7.

Detective plug wires Fouled or worn plugs Burned contact points Partially shorted ignition coil Open capacitor Poor primary circuit Carburetor problems

Engine Misfires At High Speed:1. Insufficient Dwell angle 2. Carburetor Problems Hard Starting:


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Fatima Michael College of Engineering & Technology 1. 2. 3. 4. 5. 6. 7.

Burned contact points. Improper Ignition timing Defective Ballast Resistor Low Battery Poor chohe action Open capacitor Ignition timing too much Advanced

10. Ignition timing too much Advanced enumerate the starting system problems and their causes. Battery not holding charge 1. Internal Deffect of the battery Electrolyte op.gravity under fully discharged 1.28 STP o 20 C. PbO2 Pb H2SO4  PbSO4 H2O Pbo2 clachlabe carded 2. Plabe physical determation Short circuit Antimony 3. Sediment at Bottom short circuit 4. Sulphation.

Green

Gel Electrolyte 1. Sulphation

Under certain condition

Sulphbe is former Hard nature Subsequent penetration at electrodyle.

2. Dirt on terminal / Loose Terminals 3. Electrical Leakage / Shorts 4. Excessive Electrical usage with car stopped / idling 5. Battery not used for long periods. Batter always undercharged 1. 2. 3. 4. 5. 6.

Defective Alternator / Generator Low voltage Regulator setting Infrequent (or) slow Driving with heavy Electrical loads. Excessive charging circuit resistance Sulphated Battery Too many Electrical Accessories

Battery uses excessive water 1. High voltage Regulator setting 2. Sulphated Battery


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Fatima Michael College of Engineering & Technology 3. High Temperature 11. Briefly mention the charging system problems and causes. No change rate 1. Defective alternator / Generator 2. Defective voltage regulator 3. Open or grounded field wire 4. Open circuit 5. Worn or stock brushes DC – Generator – cutout necessary Ac – Alternator – In built Rectifier Welding Transfer – Selenium Rectifier – 1 wayflow mercury rectifier. 1. 2. 3. 4. 5.

Alter nor or Generator Rectifier Cables Battery Drive bolt

Low charge rate 1. 2. 3. 4. 5. 6.

Regulator out of adjustment Defective Regulator Excessive field circuit Resistance Defective Alternator / Regulator Worn Brushes Sulfated Battery

High charge Rate 1. 2. 3. 4. 5.

Regulator out of adjustment Defective Regulator Defective Battery High Battery Temperatures An accessory drawing excessive current even when the engine is not running.

12. Explain all the reasons for engine not starting up. Due to open primary circuit 1. 2. 3. 4.

Burned or oxidized ignition points Ballast Resistor burned or open Ignition points not casing. Breaker arm binding on pivot post preventing closing of points.


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Fatima Michael College of Engineering & Technology 5. Breaker arm spring weak or broken 6. Breaker arm distorted or bent 7. Dirty Ignition points. 8. Primary lead connection loose 9. Primary winding open 10. Open ignition switch circuit Due to short circuited primary circuit Grounded primary coil winding grounded ignition switch or a lead will causes wires to burn. Possible causes for grounded primary circuit:1. 2. 3. 4. 5. 6. 7.

Ignition points not opening or closing due to improper adjustment. Ignition points not opening due to worn rubbing block on breaker arm. Faulty insulating bushing on breaker arm. Cracked or faulty insulator at distributor primary terminal. Grounded condenser Distributor to coil lead grounded. Primary coil winding grounded.

Due to faulty secondary ignition circuit 1. Corroded spark plug cable terminals 2. Cracked insulation or cables 3. Ignition coil weak or in operative 4. Moisture on Ignition coil terminals distributor cover spark plug pordains or on distributor. 5. Improper type of spark plugs 6. Cracked distributor cap or burned carbon brush in the cap. 7. Improper connection to spark plugs (Not correct as per firing order) 8. Spark plugs damaged dirts or wet porcelien cracked or gaps improperly adjusted 9. Rotor contact spring bent or broken 10. Distributor rotor grounded. 11. Distributor cap centre terminal broken or missing. Due to battery 1. 2. 3. 4.

Battery run down Terminal loose or badly corroded Improper ground Battery cable undersize Due to excessive fuel supply (flooding) Accumulation of liquid fuel in the intake manifolds as well cylinder. The engine won’t


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Fatima Michael College of Engineering & Technology start until the rich mixture formed by flooding is pumped out. 13. Explain the procedure for servicing of the distributor. 1. Remove the distributor cap by snapping the hold down clips 2. Inspect the cap wipe inside of the cap cracked chipped or carbon tracked caps must be replaced. 3. If any of the metal terminal is broken or badly burned, replace the cap slightly corroded or blackened terminals can be cleaned with fine sand paper. 4. Remove the rotor visually check for cracks, burning or corrosion of the metal tips or mechanical interference with the cap. 5. Check mechanical advance springs and counter weights turn the upper half of the distributors shaft in the direction of rotation release the shaft it should snap back if sluggish the springs are to replaced 6. Check the vacuum advance by pressing you finger against the contact breaker assembly and moving the base plate in the direction opposite to the shaft rotation the base plate should swivel with out binding. 7. Inspect the contact points for build-up and crater spots alignment, colour and weak direct may be cleaned with a few strokes of a fine cut contact point file blue burkes points indicates a bad capacities it is customary to replace capacities. 8. Test the vacuum advance 9. Check distributor contact points and clean them. 10. Re-install distributor cap and replace wiring. 11. Check battery state of charge water level and hold down clamps. 12. Check battery cables for damage, corrosion and loose connections. 13. If the battery is over charged or undercharged check the dynamo (Alternator) and regulator 14. Check drive belts and tighten or replace them as required. 15. Check the intake manifold bolts for tightness to proper specifications even a slight leak will reduce engine performance. 16. Check fuel lines for tight connections. 17. Check the weekly for leak 18. Check and accelerator linkage 19. Check crank case ventilation system. 20. Remove carburetor air cleaner and check choke valve clean or replace air filter element if necessary. 21. Check and adjust contact point dwell and ignition timing. 22. Adjust idle shed and mixture 23. Check the lube-oil dipstick level 24. Check the working of lights and horn. Adjust the head lamp for proper focusing. 25. Check steering system for easiness.

14. What are the various electrical testing equipments required for an automobile workshop. Ignition System


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Fatima Michael College of Engineering & Technology 1. Power timing light    

Stroboscope Trigger is connected to 1st spark plug (cylinder near to radiate) Timing marker is there for flywheel As engine speed the frames moves on .

2. Dwell meter: Dwell angle is a period at which contact is closed by the cam.  If gap is more do not contacts  It gap is less always contact (closed circuit). 3. Voltmeter: To measure the voltage of the circuit 4. Ammeter: To measure the current 5. Ohmmeter: Breakage of circuit can be checked. For Electrical System 1. 2. 3. 4. 5.

Voltmeter Ammeter (0-80 Amps). Tachometer Hydrometer Battery load Tester

Battery load Test done an automotive. Hydrometer (To check the specific gravity of Electrolyte for a specific Temp) Eg.1.28 at 20oC. Open volt test Each cell have 2.1 volts Cadmium Test High current Test Starter motor register is 300 amps for cracking the engine.


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UNIT – V PART – A 1. Write down the Maintenance of the fuel injection Sequential system? Fuel Tank:  Use proper sealing cap  Every month drain sediments  Every 6 month clean thoroughly,  Check low pressure pipe for leakage  Once a week drain water separator. Feed Pump:    

Every 2000 km clean hollow screw with sieve Every 5000 km clean preliminary filter Check rubber sealing washer, pre filter bowl, nylon valves, spring etc. Check Lining.

Filters    

Every 5000 km drain water/sediments Replace filter inserts as recommended Check overflow valve (if provided) for leakage Do not clean filter inserts.

Fuel Injection Pump: Every 5000 km check oil level. Drain excess oil. It level is lows top up with engine oil(only for independent lub pump)  Every 1,00,000 km replace oil (only for independence lub pump)  Every 500 km clean air breather  Use good quality high pressure pipes. 2. Write the cooling system problems and causes? Problem:  Proper cooling temp is not obtain  Piston expansion (due to improper cooling)  75 - 85 C Normal Reasons for Engine overheating:  Reduction in coolant level (loss of coolant)  Improper lubrication (High engine friction)  Belt tension is low in cooling fan & water pump.


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Cooling System problems and Causes: Engine Overheating: 1. Loss of coolant 2. Defective thermostat 3. Defective water pump 4. Collapsed radiator hose 5. Excessive Rust and seales 6. Obstructed Air passage Through Radiator 7. Late Ignition Timing 8. Combustion leak in to cooling system 9. Improper coolant Mix 10. Defective Temperature Gauge Engine Runs Too Cool: 1. Defective Thermostat 2. Defective Gauge 3. Write down the fuel system problems and causes? Fuel System problems and causes: Carburettor flooding: 1. 2. 3. 4.

Worn needle and seat leaky float Excessive fuel pump pressure Improper float adjustment. (In olden days tickler mechanisms)

Rought Idle: 1. 2. 3. 4. 5. 6.

Improper Idle mixture Poor compression Intake manifold leak Defective spark plug wires Cracked Distributor cap Stuck PCV valve

Stumbling During Acceleration: 1. Defective Accelerator pump 2. Improper Adjustment of Acc. Pump


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Fatima Michael College of Engineering & Technology 3. Ignition misfire Sluggish Performance: 1. Late ignition Timing 2. Tool rich or too lean mixture 3. Defective Advance mechanism 3. How will you check the cooling system? Cooling system checks & test: Check the coolant level. If it is low min the proper solution of antifreeze and water in an antifreeze container and fill it to the specified level Check the strength of antifreeze solution by wing either float hydrometer or a ball hydrometer. Float hydrometer: Place the end of the rubber tube into the coolant sequeeze and release the rubber bulb. The height of the float indicates the strength of he antifreeze. A thermometer and scale on the hydrometer shows the temp of the coolant & how low the temp must go before the coolant would freeze. 4. How will you check the thermostat Testing the thermostat 

  

Suspend the thermostat in a solution of coolant Heat the coolant to 14 C above the temp stamped on the thermostat, the thermostat should open. Then subonerge the thermostat in the same solution after it has cooled to 5.5 C below the temp stamped on the thermostat. It should close completely. If the thermostat does not open or close properly replace it. To check the host, squeeze it. It should not collapse easily. Replace any hose that is soft, hard, rotted or swollen. Checking for exhaust gas leakage into Dc Cooling system is done by holding the exhaust gas analyzer probe over the radiator mouth. If any leakage is there analyzer will detect it. Another way of checking is by using Bloc- check Tester. Install the tester on the radiator filler neck. With the engine running, squeeze and release the bulb. This draws on air sample from the cooling system through the text fluid. The test fluid is blue, if exhaust gas is present the fluid turns yellow.


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Figure: 5. Explain the pressure testing if the cooling system? Pressure testing if the cooling system: Fill the radiator to about 13 mm below the bottom of the filler neck. Then wipe the neck sealing surface and attach the tester. Operate the pump to apply a pressure that doe not exceed 3 PSI above the manufacturer’s specification. If the pressure old standy the system is not leaking. If the pressure drops, there are leak in the system. Make a pressure test of the radiator cap using the pressure tester. If the cap hold the pressure he cap work properly else replace it.  Check the water pump drive belt for small cracks grease, glazing, tears a splits. Replace the belt if needed.

6. Explain the cleaning of cooling system:           

Drain the cooling system Remove the thermostat and reinstall the thermostat housing and hose. If cooling system cleaner is used pour it into the radiator. Fill the coding system with water. Run the engine at fast idle for about 20 min but donot allow the water to bol. Step the engine and wait for it to cool Drain the system Use a water house to put water in the radiator to flush out loosened scale and rust. Flushing gun can also be used to flush the water Continue to flush until the water runs clear After draining the system, install the thermostate and housing and reconnect the hoser. Fill the radiator with proper coolant.


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 

Pressure check the radiator for any leaks if so the radiator has to be rapaired.. Check the water pump for any noise or leaks. If present replace it. Normally water pump requires no service

7. Write shortly about antifreeze solution? Antifreeze: To prevent freezing of the water in the cooling system anti freeze is added to form the coolant The most commonly used antifreeze is ethylene glygol. A mixture of half water & half ethylene glycel is the recommended coolang proportion. The antifreeze coolant performs three basic jobs (i) (ii) (iii)  

It lowers the freezing point of the engine coolant to -37 C It raiser the boiling point of the coolant to 108 C It helps protect the cooling system metals from deposits and corrosion. Corrosion inhibiter, foam inhibitor are some of the important additives for antifreeze. There are two types of ethylene –glycol anti freeze, high silicate and low silicate. High silicate are wed in aluminum cylinder head engineer and low silicate are used in engines with carrion cylinder block and header

8. Enumerate the lubricating System Troubler, and Services? Problems:  Engine uses too much oil Engine operated at high speeds Engine parts may be weared Engine Seating may be defective  Oil –Pressure A weak or broken relief valve spring A worn oil pump A broken a cracked oil line An obstruction in the oil line In sufficient or thin oil Worn Engine bearings Leaking oil fitter


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

Excessive oil pressure A struck pressure – relief valve Wrong spring in the pressure relief valve A clogged oil line Thick oil.

Lubricating System Service Park the vehicle on a level surface Turn the engine ff check the oil level by withdrawing the dip stick. Also check any dirt particle are present in the oil by rubbing the oil. If needed replace the oil. Change the oil periodically. How often the oil, should be changed depends primarily on how the vehicle is used. There are normally two recomendature. Schedule – I Changing engine oil & oil fitter every 5000 km if      

Most trips in warm weather are less than 6 km Most trips in below freezing weather are less then 16 km. Most trips include extended idling Low speed stop and go operation Operating in duty condition Towing a trailer.

Schedule – 2 Changing the oil every 12,500 km , if the vehicle is used several km daily and none of the items in schedule 1. apply.  Change the oil filter with every oil change or every other oil change, according to the operating conditions.  Whenever oil pan is removed for engine or oil pump service remove all old gasket material from the gasket surface. The pan and engine block. Check the gasket surface for flatness.  Check the oil pump if badly worn, services the pump or replace it.  Check the pressure relief valve for good operation if not replace it. 9. Write down the procedure for changing engine oil Change in oil: Raise the vehicle on a lift


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Fatima Michael College of Engineering & Technology Place a new maintenance sticker on the vehicle write in the odometer reading, the date, and the type of oil used. Oil-Filter Service: Change the oil filter wire every oil change or every other oil change according to the operating conditions. Most filter are unscrewed and a new filer installed by hand. You may need an oil-filter wrench to loosen the old filter. Clean the filter mount and recess with a clean shop towel. Make sure the old filter sealing gasket does not remain on the ( ) coat the sealing gasket on the new filter wire oil. Then install the new filter tighter it until the gasket contacts the filter base on the ( ) Oil Pan service: Whenever the oil pan is removed for ( ) or oil pump service, clean the pan, oil pick up and oil pump. Remove all old gasket material from the gasket surfaces on the pan and block. Check the gasket surfaces of a sheet- metal pan for flatness. Over tightened screws raise the metal around the screw holes. This can prevent sealing of the new gasket. Top the holes lightly with a hammer until the gasket surface are flat. 10. Write down the procedure to dinging with sketches?

All blows are made by swinging with a wrist action in a circular motion, rather than a follow through as used when driving a Nail.

In all dinging operation the hammer blows should be spaced approximately 6 to 10 mm a parts and in rows one besides the other approximately 100 to 100 blows are made / per minute.


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In dinging operations the dolly is placed inside of the damaged panel and held against its, surface by pressure exerted by the foe arm.

Choose a dolly with the same slightly smaller radius than the curvature of the sheet metal being repaired. Method of Trimming a flange:

The general purpose dolly is placed in the damaged flange (r what is left only) and a downward as well as outward pressure is applied on the dolly.  The flange is formed or reshaped by on the dolly hammering starting at the outer edge of the


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Fatima Michael College of Engineering & Technology flange gradually working towards its inner edges as indicated by arrows until it is perfectly round and smooth.

Method of forming a Bead

The dolly is held tightly underneath the centre line of the already marked off metal and it is hammered until slightly structed. The outer edge and ends of the bead are then formed by alternate off the dolly hammering using the square face of a bumping or balanced dinging hammer. Using the Low crown dolly in shaping metals

11. Write shortly about Repainking Grit size - 50,100, 200 , 500 marks used


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Fatima Michael College of Engineering & Technology Types of paint  Acrylic Lacquer Nitrocellulose Enamel

vehicle pigment drier

Lac inseat Searification also called Lac insets are in lakhs on a certain trees

Acrylic is not a metal Enamel:  Drive forest of evaporation of the reducer. The carrier is oxidized & polymerized from the sun so chemical reaction takes place.  They retaints its fully glow and need not be polished  They are usually soft, they require longer driver and insoluble to ordinary solvent. There are usually soft because they require longer time to dry insolution to ordinary solvent. Rubbing components:Used to remove dest & spray dust , & orange peel To improve lac surface Is a time abrasive in neutral medium of a creamy construction. 12. Draw a typical spray painting gun and painting process?

A  Air gap B  Fluid tip C  fluid Needle D  Trigger E  Fluid adjustment screen F  Air valve G --. Spreader adjustment valve H Gun body


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Spray Guns of Painting

When spraying a panel use alternate right & left strokes triggering the gun at the beginning and end of each strake the spray pattern should overlap one-half the previous stroke for smooth coverage without streaks.


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Too close paint goes on heavy-tends to say

Too Far causes excessive dusting sandy finish

13. Draw the different types of tools use din body denting / Tinkering

Short curved pick

Long curved pick


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Deep throat straight pick

Long tea handle chisel bit pick

Double end lower back and quarter panels spoon

Double end Heavy duty driving & tender beading tool

Half Moon file and holder

Piercing punch

Double end door and side apron spoon

Adjustable flexible file and holder

Holding a balancing Dinging hammer by ¼ th of the disbance from the end of handle and hl in loosely in the hrd.


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Balanced donging hammer

Long pick hammer

Short pick hammer

Taper shank cheisel pick hammer.


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Fatima Michael College of Engineering & Technology General purpose dolly

Low crown really

Bead dolly

Head dolly

Toe dolly

edge dolly

Unloding slightly damaged body panel buckling wth dolly

On the dolly Hammering

off the dolly hammering

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