manual despre kitul de ambreiaj

Failure DiagnosisLuK’s guide to troubleshooting clutch-system

failures and malfunctions

agricultural vehicles

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05_051148luko_E 21.11.2005 14:49 Uhr Seite 2

A

B

C

D

Clutch slip..................................................................................................................................................15-18

Clutch judder........................................................................................................................................19-22

Clutch noise...........................................................................................................................................23-26

LuK-tips on avoiding clutch systemfailures and malfunctions ...................................................................................................4-5

Clutch not clearing.......................................................................................................................6-14

General tips on installing commercial vehicle clutches ..............................................................................24-31

Diagnostic charts........................................................................................................................32-35

ContentsPages

This manual is for the use of all of ouremployees, business associates, andfriends who sell, install, or report onLuK-clutches. It is primarily intended tobe a source of information that willsimplify diagnosing the causes offailures and malfunctions of commer-cial vehicle clutch systems. Its contentis confined to typical clutch-systemdefects and is not aimed at beingcomplete.

© 2005LuK-Aftermarket Service oHG, D-63225 Langen, GermanyTechnical Customer-Service Dept.Reproduction, copying, or translation hereof in whole or in part requires our prior writtenpermission and crediting the source

TECHNICAL HOTLINE Telephone:+49 (0) 61 03-753-239

CATALOGUE HOTLINE Telephone:+49 (0) 61 03/753-219/229/232/233/239/280Fax:+49 (0) 61 03-753-351

LuK-Aftermarket Service oHGPaul-Ehrlich-Strasse 21D-63225 Langen, GermanyTel. +49 (0) 6103-753-0Fax +49 (0) 6103-753-295Internet: http://www.LuK-AS.de

LuK-Aftermarket Service oHG

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4

LuK tips on avoiding

• FlywheelThe running surface of the flywheel, which mates to the drivenplate, may show signs of wear after extensive mileage. Scoring,glazing, and/or gouges indicate that the flywheel has been over-heated, and these must be removed, however they should never berefaced beyond the tolerances laid down by the manufacturer. It isimportant however, that the same amount is taken from the boltingsurface. Also take this opportunity to check the starter ring gear.

• Spigot (Pilot) bearingThey may be no larger than a thimble, but they can cause seriousproblems. If they bind, the clutch may fail to disengage. They canalso cause noise and angular misalignment, and thus damage to thedriven plate. A missing spigot (pilot) bearing may cause the trans-mission input shaft to wobble and destroy the torsional-vibrationdamper and the input shaft bearing.

• Oil sealsLeaking oil seals can severely damage the clutch. Even slight tracesof grease or oil can adversely affect clutch operation. Traces of oilin the bell housing or on the clutch driven plate indicate that sealswill need to be replaced. Seals on older vehicles with high mileageshould always be replaced as a precaution. The major cause ofclutch failures and malfunctions is still leaking oil seals.

• Driven plateAlthough each and every driven plate is checked for correct opera-tion before it leaves the LuK factory, it cannot be ruled out that theymight suffer a damage on their way to the garage. Every driven plate should be checked for lateral runout (the maxi-mum tolerance is 0.5 mm) prior to installation. Excessive lateral run-out is not covered under warranty.

• Release bearingRelease bearings cannot be checked for correct operation at garagelevel. They should always be replaced whenever the clutch is re-placed. The bearing should slide freely on their guide tube withouttilting. A worn running surface will invariably cause noisy operation.

• Release-bearing guide tubesCheck the guide tube for correct fitment. Guide tubes should becentered and parallel to the transmission input shafts. Damaged orworn areas on guide tubes may prevent the release bearing fromsliding freely. This can lead to judder, clutch slip, heavy or difficultclutch operation. Damaged or worn guide tubes should always bereplaced as part of a professional clutch replacement.

• Release forkCheck the release fork for ease of operation. Excessive play inrelease-shaft bushes reduces release bearing travel. Uneven wearon the contact points will cause the release bearing to tilt and pre-vent the release bearing from sliding smoothly on its guide tube.Worn, bent, or broken release forks may prevent the clutch fromdisengaging.

• Release shaftThe release shaft will have to be removed before it can be inspectedfor wear or damage, since the bearing surfaces and bearings can-not be inspected while in place. Damaged or worn shaft bearings

will cause the shaft to tilt, which will create binding and/or a jud-dering clutch. Re-lubricate the bearings before replacing the shaft.The LuK-AS part number for the correct high-melting-point greaseis 414 0014 10.

• Clutch cableClutch cables cannot be accurately checked for proper operation atgarage level. Since clutch cables are subject to wear, they shouldbe replaced whenever clutches are replaced. Make certain thatclutch cables are correctly routed when installing them. Theyshould never be routed around sharp corners or kinked. LuK-AS’sline of clutch cables is covered in the associated sales literature(only LHD).

• Centrally actuated release mechanismLike the clutch, the centrally actuated release mechanism is subjectto wear, which may not always be visible during normal operation. If only the clutch is replaced, it might be that the centrally actuatedrelease mechanism could fail soon after clutch replacement, neces-sitating a second, unnecessary visit to the garage, since the worncentrally actuated release mechanism was not identified the firsttime around. Professional clutch replacement should always involvereplacing the clutch pressure plate, driven plate, and centrallyactuated release mechanism.Please take care to use the correct fluid for refills. In some casesyou must use brake fluid (black seal) , in others mineral oil (greyseal).

• AlignmentCorrect alignment of the clutch is frequently ignored. If clutcheshave not been correctly aligned, they will start juddering or fail todisengage immediately afterwards. The clutch should thus alwaysbe checked for correct alignment on the flywheel.

• LubricantsGrease that contains no suspended particulates should be used forlubricating splines and release bearings/guide tubes. LuK-AS hasthe correct high-melting-point grease for clutch replacements avail-able under Part No. 414 0014 10. Once grease has been applied tothe splines on the gearbox input shaft, slide the driven plate’s hubonto the shaft and remove any excess grease.Chemically nickel-plated hubs should not be lubricated.

• The Service life of clutch facingsSince friction clutches are dry clutches, and wear during the slip-ping phase, i.e., while the rotational speed of the driven plate isbeing brought up to that of the flywheel, is normal. The basic pre-requisite for a long clutch life is ensure that the clutch releasemechanism is in perfect working order and that the clutch is notabused while driving. Clutch life may be adversely affected by thefollowing:• revving up the engine when starting off or starting off in the

wrong gear,• stop-and-go driving in heavy traffic,• manouvering in close confines,• slipping the clutch for extended periods,• preventing the vehicle from rolling back on inclines by slipping the

clutch, and failing to use the accelerator pedal to match speedswhen downshifting.

Major causes of problems:

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5

clutch-system problems

Certain criteria should be kept in mind and certain proceduresobserved when assessing the malfunction of clutch systems. Dia-gnosing failures or problems in order that they may be efficientlyand permanently eliminated. The following should be observed.

1. Determine the reason(s) for the complaint.

2. Troubleshooting

3. Diagnose the failure or problem.

4. Eliminate the cause of the failure or problem.

The reason(s) for the complaint provide basic information in thesubsequent troubleshooting, which may identify one or more cau-ses for complaint. The clutch should be visually inspected and sub-jected to dimensional checks if necessary, either while it is stillinstalled or after it has been removed. This will provide an indicati-on that will help in the correct diagnosis and will lead to the repairor replacement of the affected parts.

Determining the reason(s) for the complaintAccurate information regarding the complaint is indispensable if thecauses are to be eliminated. Since the reasons may be counted onthe fingers of one hand and it can be readily and clearly described.

The five possible reasons for complaints aboutclutches:

TroubleshootingTroubleshooting confined to a specific area can start once a clear-cut statement of the reason(s) for the complaint has been identified.However, the error of immediately starting to remove the clutch,which, in most cases, represents the bulk of the work to be carriedout, is frequently undertaken. Where as searching for the cause ofthe failure/ or fault in areas where it might be eliminated using rela-tively simple means, namely, in areas of the clutch system otherthan the clutch itself is frequently neglected. The cause of clutch failures or faults is not always attributable to aclutch malfunctioning. A closer look would show that there are avariety of external influences that can affect clutch operation.

A heavy clutch pedal

Noise

Failure to disengage

Slipping

Juddering

Here are a few examples:Incorrectly adjusted carburettors or fuel-injection systems maycause rough idling that will be reflected in a juddering clutch whiledriving.

An incorrectly adjusted ignition system may also cause phenomena,such as a judder when the clutch is engaged. In addition, “runningon” after the engine is switched off transmits sudden jolts to thetangential leaf springs. Bent tangential leaf springs will causedisengagement problems.Damaged or weak engine mountings will cause the engine to movefrom it’s position and then ‘bounce’ back when the clutch isengaged, which causes a transition between static and dynamiccoefficients of friction at the contact surface of clutch facings andresults in judder.

Heavy accelerator pedal actuation also causes juddering. A combi-nation of a binding accelerator linkage and very weak enginemounts causes the drive train to rock.

A worn-out clutch cable causes disengagement problems orjuddering. Failure to correctly adjust clutch cables will cause any-thing from slipping and disengagement problems to the totaldestruction of clutch components.

A malfunctioning hydraulic clutch-actuation system will causedisengagement problems or judder.

Distorted transmission mountings or missing spigot (pilot) bearingscause angular misalignment between the crankshaft and transmis-sion input shaft which results in judder or disengagement problems.The subsequent ‘Wobbling’ motion of the driven plate during engage-ment and disengagement because this angular misalignmentcauses fractures around the rivets that hold the segments in place.

Worn splines on the transmission input shaft will cause erraticmovement during load changes, which can bend tangential leafsprings and cause disengagement problems or juddering.

Copies of this page may be ordered from our Central Customer-Training Dept.

Tel.: +49 (0) 6103-753-251Fax: +49 (0) 6103-753-293

Failure diagnosis/causes of failures

Right Wrong!

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Clutch not clearingALinings torn off1.

2. Linings torn off

Causes: The rotational speed of the drivenplate has exceeded the burst speed ofthe lining material, this conditionoccurs when the vehicle is allowed tocoast with the clutch pedal depressedand the vehicle speed exceeds themaximum speed of the gear selected.This sort of damage is independent ofengine rpm. The determining factor istransmission input-shaft rpm.

Causes: • Worn flywheel face not machined flat.

6

Causes:• Lack of release bearing clearance• Engine vibration damper defective• Fuel injection system incorrectly

adjusted

Pressure plate lugs broken3.

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Clutch not clearing A

Causes:• Engine vibration damper defective- Engine torsional vibrations have

caused the circlip securing the pivotpin to pop off.

• Fuel-injection system incorrectlyadjusted

Broken pivot pin 5.

4.

Causes:• Incorrectly adjusted release bearing• Worn out torsion damper on the

crankshaft• Incorrect setting of injectors

A release-lever pivot pin hasdrifted out.

7

Pressure plate broken

Causes:• Pressure-plate overheating due to

slipping the clutch for excessivelylong periods

• Clutch was slipping due to wornfriction

• Binding in the release system• Defective slave cylinder• Oil on linings due to a leaking shaft

seal

6.

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Clutch not clearingACentering ridge on flywheelbroken off7.Cause:• Clutch incorrectly installed- Clutch not aligned to the flywheel

ridge- Bolts not torqued down evenly

8

Tangential leaf spring broken8.

9. Tangential leaf spring bent

Causes:• Play in the drive train• Driver error- Poor gear-shifting habits

Causes:• Play in the drive train• Driver error- Poor gear-shifting habits• Improper storage- Clutch fell or was dropped during

installation

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9

Causes: • Incorrectly adjusted release bearing• Faulty release mechanism• Release bearing failure

Worn clutch levers 11.

10.

Causes: • Incorrectly adjusted release bearing• Faulty release mechanism• Release bearing failure

12.

Broken clutch levers

Worn spring fingers 12.Causes: • Release bearing seized• Faulty release mechanism• Incorrectly adjusted release bearing

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Clutch not clearingA

10

13. Clutch cover pressing bent

Causes:• Fitting fault- Mounting bolts not uniformally

tightened- Dowels in flywheel not correctly

aligned

14. Pivot ring removed

Causes: • Fitting fault- Pivot ring removed following fittingPivot ring is not an aid to fitment

15. Hub splines damaged

Causes: • Clutch incorrectly installed- Captive disc shaft incorrectly aligned- PTO hub shaft incorrectly aligned- Pressure plate not aligned to

flywheel step- Pressure plate not torqued down

correctly - Wrong drive plate installed

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Causes: • Spigot (pilot) bearing worn• Angular misalignment of engine and

transmission

Clutch disc distorted 18.

17.

Causes:• Improper installation- The clutch disc carrier was damaged

by the transmission/PTO input shaftdue to misalignment when the trans-mission was reinstalled on the engine

Hub splines chewed out on oneside, tapered wear on splines

11

Cause:• Hub splines were not lubricated.

16.Rust on the hub

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Clutch not clearingAClutch disc distorted19.Causes:• Improper installation- The clutch disc carrier was damaged

by the transmission/PTO input shaftdue to misalignment when thetransmission was reinstalled on theengine

12

Segment cushion broken20.Causes: • Improper installation- The transmission was allowed to drop

down during installation.• Engine-transmission angularly

misaligned

Fouling marks on the hub21.Causes:• Fitting fault- Driven plate fitted wrong way around• Incorrect driven plate

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Cause:• Vehicle has been left standing for a

long time

Facing stiction 22.

Causes:• Sintered friction material not bedded

in. Tractor was put under heavy loadimmediately following fitting.

• Excessive slip due to fitment ofclutch disc against worn andgrooved flywheel

Sintered friction materialdestroyed 23.

Causes:• Worn release fork• Worn guide tube• Worn release shaft bearings

24.Release-fork-bearing surfaceworn

13

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Clutch not clearingARelease bearing claering

Casing and bearing damaged26.

27.

25.

Gearbox snout worn

Causes:• Insufficient bearing preload

(specification 80-100 N)• Incorrect adjustment of the release

fork

Causes:• Overheating of the release bearing

due to incorrect clearance causingloss of grease and break up of thebearing

Causes:• Incorrect adjustment of the release

fork• Offset wear by the release fork

14

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Clutch slip B

Cause:• Overheating• Lining worn beyond permissible

limits

Cause:• Incorrect preload

Severe scoring and glazing onthe pressure plate

Lining surfaces glazed 3.

2.

1.

Causes: • Oil on linings- Leaking shaft seal(s)• Lining coefficient of friction decreased

due to allowing the clutch to slip fortoo long (overheated linings).

Diaphragm-spring fingers worn

15

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16

Clutch slipBGrease/oil on linings4.

5. Linings worn down to the rivetheads

Causes: • Too much grease used on hub- Excess grease on the hub splines

was not removed and grease ran• Leaking engine or transmission shaft

seal out onto the linings.

Causes: • Excessive lining wear - Vehicle was still being driven, even

though the clutch was slipping.• Driver error- Allowing the clutch to slip for too

long• Improper use of the clutch• Defective release system

6. Friction material worn to rivet head

Causes: • Excessive friction material wear.

Vehicle was still being driven, eventhough the clutch was slipping

• Clutch slipped for long periods?• Improper use?• Defective release system

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Clutch slip B

Causes: • Worn flywheel was not replaced.• Worn flywheel mating surface was

not turned down.

Lining on flywheel side scored 7.

Causes: • Clutch disc installed backwards• Incorrect clutch disc installed • Flywheel modifications not made

Incorrect fitment 8.

Causes: • Release-shaft bearings not

lubricated• Release shaft and/or its bearings

worn

Release shaft binding 9.

17

➞

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Clutch slipBWorn clutch levers10.Causes:• Incorrectly adjusted release bearing• Faulty release mechanism

18

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Clutch judder C

Causes:• Oil or grease on the facing• Stiff clutch linkage• Worn engine mountings• Worn transmission linkages• Engine badly tuned

Causes: • Excessive clearance in the drive train• Driver error- Poor gear-shifting habits• Improper storage- Clutch fell or was dropped during

installation

Heavy chatter marks on thepressure plate

Release-fork bearing surfaceworn 3.

2.

1.

Cause: • Release fork worn- Release-bearing mountings worn

Tangential leaf spring bent

19

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Clutch judderCGrease/oil on linings

Lining on flywheel side scored5.

6.

4.

Release-fork bearing surfaceworn

Causes: • Too much grease used on hub

splines- Excess grease was not removed

during installation and grease ranout onto the linings.

Causes: • Worn flywheel was not replaced.• Worn flywheel mating surface was

not turned down.

Causes: • Incorrect installation- The transmission input shaft has

been forced into the driven platesplines (the driven plate was notaligned when the pressure platewas installed).

• Incorrect driven plate fitted

20

➞

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Clutch judder C

Cause: • Worn release fork mountings- Worn guide sleeve

Release fork worn

Transmission input shaft worn out 8.

7.

Cause: • Worn input shaft was not replaced

Release shaft binding 9.Cause: • Worn release shaft and/or bearings

21

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Clutch judderCFlywheel glazed and scored10.

11. Faulty clutch mechanism

Cause: • Flywheel not refaced/replaced.

Cause: • Worn cable.- Inner cable worn and unable to

move freely.- Old cables whilst they may look

sound are worn.

22

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Clutch noise D

Causes: • Insufficient preload• Release bearing seized

Causes: • Clutch disc installed backwards• Incorrect clutch disc installed• Flywheel modifications not made

Diaphragm-spring fingers worn

Fouling marks on the hub 3.

2.

1.

Causes:• Fitting fault- Driven plate fitted wrong way around• Incorrect driven plate

Signs of wear on torsionalvibration damper

23

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24

Torsion damper retainer platebroken

A torsion spring has broken out5.

4.Causes: • Driver error- Driving too long at excessively low

engine speeds has caused thedamper's efficiency limits to beexceeded.

• Wrong driven plate installed

Causes: • Oil on clutch linings• Improperly tuned engine• Defective release system• Wrong driven plate installed• Driver errorJuddering damages the torsonal-vibration damper.

Causes: • Worn spigot (pilot) bearing• Angular misalignment of engine and

transmission

Hub spline chewed out on one side,tapered wear on hub splines, tor-sional-vibration damper destroyed

6.

Clutch noiseD

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Clutch noise D

Causes: • Badly tuned engine- Faulty or incorrectly set injectors• Induced torsional vibration in tractor

PTO

Causes: • Oil on clutch linings• Improperly tuned engine• Defective release system• Wrong driven plate installed• Driver errorJuddering damages the torsonal-vibration damper.

Worn splines

Release bearing worn 9.

8.

7.

Causes: • Insufficient bearing preload

(Specification 80-100 N)• Incorrect adjustment of the release

fork

Casing and bearing damaged

25

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Clutch noiseDGear box snout worn

Release-fork bearing surfaceworn11.

10.Causes:• Offset wear by the release fork• Incorrect adjustment of the release

fork

Cause: • Defective release system- Worn release-shaft bearings- Worn guide tube

Release fork worn12.Cause: • Defective release system- Worn guide tube- Worn release-shaft bearings

26

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27

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The LuK Clutch Course

28

Dual-mass flywheels: their design and operation

Dual-Mass Flywheels redistribute the mass moment of inertia and thus shift resonancefrequencies to a range well below the normal operating range. The periodically occurringcombustion cycles inevitably cause fluctuations in rotation rates. The spring/dampingsystem of a Dual-Mass Flywheel virtually isolates the rest of the drive train from thesefluctuations and provides the smooth running of all components of the secondary mass,(clutch, driven plate, transmission, and drive shafts) that follow in the drive train.

1

2

34567890ß“„”

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Primary rotating mass and damperhousingSecondary rotating mass and frictionsurfaceCover for primary rotating massHubArced compression springTubular spring guideFlange and diaphragm springGrease reservoirMembrane sealFriction and supporting ringCaged ball bearingsO-ringSealing and insulating capDiaphragm springs providing basicfriction controlLoad-transmitting friction washerDiaphragm springSheet-metal cover plateRivetWasherCentering pinStarter ring gearVentilation slotsMounting holePositioning holeLaser weldDiaphragm-spring clutch Rigid driven plate

Transmission Transmission

Schematic

The previous style

Resonance ataround 1,300 rpm

Engine FlywheelClutch

Driven-PlateTorsional-VibrationDamper

Transmission

Dual-mass flywheel

Engine Primäryrotatingmass

DMF Torsional-VibrationDamper

Secondary rotating mass FlywheelClutch

Transmission

Resonance ataround 300 rpm

How it works(Transmission of torsional vibrations)

Conventional flywheel and driven platewith torsion-vibration damping

Engi

ne s

peed

[rpm

]En

gine

spe

ed [r

pm]

Dual-mass flywheel

Time (s)

Time (s) EngineTrans-mission

05_051148luko_E 21.11.2005 14:50 Uhr Seite 28


400

300

200

100

0

0 10 20 30 40

Rotation angle [°]

En

ng

ine

to

rqu

e [

Nm

] Partial loop in the normal

operating range with

low damping

High damping

during load changes

Computed

Measured

29

Damped Flywheel Clutch – their design and operation

Primary rotating mass and damper housingSecondary rotating mass and friction surfaceCover for primary rotating massArced compression springMembrane sealTubular spring guideCover retaining ring and flangeVentilation slotsStarter ring gearMembrane sealSheet-metal supportBalance weightVentilation slotsCaged ball bearings with sealing and insulating capAllen-head screwDiaphragm springLoad-transmitting friction washerSheet-metal retainerDiaphragm springDowel pinTensioning pinGrease reservoirLaser weldAperture for accessing retaining bolts Pressure plate with friction surfacesVentilation slotsDiaphragm springTilt ringsRiveted studLeaf springRivetAperture for accessing retaining boltsHubAllen-head screwDiaphragm springSegment rivetSpring segmentLining rivetClutch liningsRivetHubAnnular mass (primary rotational mass)Rivet

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30

Sensor-diaphragm spring

Pivot for the maindiaphragm spring

Adjusting wedge

Main diaphragm spring

Sens

oor p

ress

ure

Rele

ase

pres

sure

new wornnew

Self Adjusting Clutches – their design and operation

CoverAdjusting ring (chamfered ring)Compression springDiaphragm springSensor diaphragm springStudStudLeaf springPressure plateStopDriven plate

1234567890ß

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31

Driven plates for light trucks – design and operation

Predamper friction washerPredamper diaphragm spring (1st stage)Predamper hub flangePredamper compression springsPredamper compression springsPredamper cageMain-damper diaphragm spring (1st stage)Centering conePredamper diaphragm spring (2nd stage)Predamper load-transmitting washerPredamper cageMain-damper diaphragm spring (2nd stage)Main-damper friction washerLining rivetFriction liningsSpring segmentSegment rivetCounter plateMain-damper compression springsMain-damper compression springsDriven plateHubMain-damper friction washerMain-damper auxiliary flangeSheet-metal spacer

2000

1000

0

-1000

0 0,1 0,2Time (s)An

gula

r acc

eler

atio

n [rp

m/s

2 ]

No torsional-vibration damper

Vibrations at idle speed

0 0,1 0,2Time (s)

EngineTransmission

With a torsional-vibration damper

12

34567

89

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05_051148luko_E 21.11.2005 14:50 Uhr Seite 31

The LuK way to...

32

...cost-effective, efficient clutch replacements

D

Top priority:● Are the right clutch components for the vehicle in

question being used?● Are all of the special tools that might be needed

for clutch replacement available?Qualified LuK associates observe thefollowing procedures, which are essential toprofessional clutch replacement:1 Check the spigot (pilot) bearing for security and replace

it if necessary.2 Check the engine and transmission shaft seals for

leakage and replace them, if necessary.3 Check the mating surface of the flywheel for scoring and

gouges. If its mating surface needs to be machined, makecertain that the prescribed tolerances are maintained.Note: The area around the bolting surface should bemachined by the same amount.

4 Check the driven plate for lateral runout using LuK-ASchecking and straightening fixture (AS Part No.400 0006 10,which accommodates driven plates up to 295 mm indiameter). Center the driven plate using a LuK centeringfixture.

5 Check the transmission input shaft for damage. Use onlygrease containing no suspended solid matter for lubri-cating its splines, the release bearing, and its guide tube.LuK-AS has the right high-melting-point grease in its pro-duct line under AS Part No. 414 0014 10. Once grease hasbeen applied to the input shaft splines, slide the drivenplate onto them and wipe off any excess grease. Greasecontaining suspended solid matter is unsuitable for thispurpose.Chemically nickel-plated splines should not be lubricated.

6 Make certain that the driven plate is installed the rightway around, with its engine side facing the engine andits transmission side facing the transmission.

Clutch pressure plateClutch driven plateRelease bearingFlywheelTransmission input shaftCrankshaft

7 Check the release bearing guide tube for wear andreplace it if necessary. Use grease when reinstallingthe release bearing only if it has a metal inner boreagainst a metal guide tube and wipe off any excessgrease once it has been installed.

8 Torque the pressure plate down in several stages,tightening the bolts diagonally opposite and insequence, securing them with a dab of locking com-pound once they have been finally torqued down, ifnecessary.

9 Make certain that the clutch pressure plate iscentered on the flywheel. If the pressure plate iscentered by a step, check the condition of the step inthe flywheel and the mating step in the pressure plate.

0 Check for any uneveness on release lever height. If found to be uneven do not adjust them but returnthe unit to LuK. Adjustments carried out by non LuKtrained staff will void any warranty.

ß Check the clutch actuation mechanism for properoperation and wear. Replacing clutch cables is part ofany properly performed clutch repair. On mecha-nically actuated clutches, check their mechanicallinkage and all bearings for wear.

“ Bleed the hydraulic system, if necessary adjust theslave cylinder piston rod travel. Check whether thepiston returns to its retracted position.

„ Check the alignment of the bell housing on the engine.Replace any worn dowel pins.

” Release bearings that are designed to operate with acertain amount of free play, set the clearancebetween the release bearing and the releasefingers/levers to 2 mm to 3 mm. Release bearings thatare designed for constant contact should run with apretension to 80 N to 100 N. Release bearings with aplastic sleeve should be used in combination withmetallic guide tubes only.

/:’M?!

05_051148luko_E 21.11.2005 14:50 Uhr Seite 32


33

4

81

5

2

3

7

6

9

0

Driven plates for heavy vehicles – their design and operation

Lining rivetInner compression spring on primary damperOuter compression spring on primary damperCompression spring on secondary idle damperSplined hubSegment rivetHub flangeLiningSpring segmentRetainer plate

12

3

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Release travel (mm)

Clutch coverDiaphragm springPressure plateLeaf springRoll pinRelease bearing, complete with installation kitSteel-wire hoopStud

Pull type diaphragm spring clutch

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Tractor clutch with independent PTO


HousingMain drive pressure plateP.T.O. pressure plateDiaphragm springMain drive plate(with sintered metal pads and torsion damper)

P.T.O. plate(with organic facing and rigid centre)

Main drive release arm P.T.O. release armFlywheelEye boltRelease arm conrodAdjusting screwLock nutAdjusting nutRoll pinAnti-rattle springPivot pin

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What are theparticularsymptoms?

Which compo-nents might bedefective?

What should bechecked beforeclutch removal?

What can bedetermined afterremoval?

What might becausing theproblem(s)?

D I A G N O S T I CP R O C E D U R E S

START OFF THE CUSTOQ U E S T

TEST DRIVE:Does the clutch judder,particularly under certaincircumstances, e.g., whenreversing uphill?

Erratic rotational motion of thecrankshaft or transmission inputshaftErratic friction between drivenplate/flywheel/pressure platePressure plate engages off-axis.Clamp load increases erratically,driven plate binding on trans-mission input shaft.

ACTUATION:Pedal mechanismClutch cableAdjustmentRelease shaftMaster/slave cylindersHydraulic linesDRIVE TRAIN:Engine management, Engine suspension.Transmission suspension, Prop shaft, drive coupling

DRIVEN PLATE:Facing oily, facing greasy, contactpattern incorrect.COVER ASSEMBLY:Chatter marks, leaf springdeformed, diaphragm spring bent,cover warped.FLYWHEEL:Surface incorrect.RELEASE SYSTEM:Release bearing, release shaftbearing, guide sleeve.

QUICK TEST:Set the handbrake.Disengage the clutch and startthe engine.Select fourth gear.Press the accelerator and slowlyengage the clutch.Does the engine stall as it should?TEST DRIVE:Disengage the clutch while in4th/5th gear.Press the accelerator and engagethe clutch.Does the engine speed up?

Insufficient friction between drivenplate and flywheel/pressure plate.Excessive wear on drivenplate/flywheel/pressure plate.Insufficient clamp load.

ACTUATION:Pedal mechanismAdjustmentClutch cableMaster/slave cylindersHydraulic linesDRIVE TRAIN: Has no effect!

DRIVEN PLATE:Oil/grease on liningsLinings glazed or worn thinPRESSURE PLATE:Pressure plate overheatedPressure plate severely scored,worn thin, diaphragm spring weakFLYWHEEL:Flywheel mating surface scored,flywheel worn thinRELEASE SYSTEM:Release bearing, guide tube,release fork, bearings

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SERVICE IDEAS FOR THE WORLD OF CLUTCHES.

LuK TROUBLESHOOTING AAGRICULTURAL VEHICLES

T H E C L U T C HJ U D D E R S

T H E C L U T C HS L I P S

LuK TROUBLESHOOTING AAGRICULTURAL VEHICLES

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Regarding malfunctions:What is malfunctioning?How was the problem noticed?How long has it existed?

Regarding wear:Clutch mileage?Is it the original clutch?Has the clutch beenabused?

Regarding usage:Is the vehiclenew?Who drives it?

Regarding past repairs:Have the clutch and/or transmissionbeen repaired?

TART OFF BY ASKINGHE CUSTOMER THESE

U E S T I O N S :

QUICK TEST:Start the engine, shift into reverse.Does the transmission make anoise when shifting gears?

The pressure plate is not retract-ing or is dragging. The driven plateis not free to rotate. Input shaft isseized in the spigot bearing.

ACTUATION:Pedal mechanism, adjustment,clutch cable, release fork rotatingon its shaft or broken, travel ofmaster/slave cylinders,master/slave cylinders leaking,hydraulic lines, fluid levels, air inthe system, clutch servo stroketoo shortDRIVE TRAIN:Hardy spicer joints, drive shaftuniversal joints/splines

DRIVEN PLATE: Hub splines rusted,linings rusted onto flywheel/pres-sure plate, linings fractured/tornoff, excessive lateral runout, liningbackings bowed, driven plate in-stalled backwards, torsional-vibra-tion damper springs have brokenloose, hub splines damaged, incor-rectly machined, or unlubricated.PRESSURE PLATE: Pressure platebroken, leaf springs bent or broken,diaphragm-spring fingers severelyworn, cover distorted, diaphragmspring bent or broken, inner sur-face of diaphragm spring scoreddue to excessively long travel.FLYWHEEL: Has no effect.RELEASE SYSTEM: Release bearing, release shaftseized in its bearings, guide tube,release fork broken or bentSPECIAL CASE: Driven plate con-tinues to rotate when the clutch isdisengaged because the transmis-sion input shaft is seized in thespigot (pilot) bearing.TWIN-PLATE CLUTCHES: Are theadjuster slides contacting theflywheel?COIL-SPRING CLUTCHES: Cam(s)or release-lever mountings brokenPULL TYPE TWIN-PLATECLUTCHES: Spacers have slippedout of position.

COMPONENT FAILURESDefective parts in the clutch itself?In the release system?ADVERSE EFFECTS CAUSED BY THE DRIVE TRAIN?Engine, transmission, other drive-train componentsEXTERNAL CAUSESNormal wearImproper useIncorrect repair procedures

QUICK TEST:Press the clutch pedal. Does it feel heavy?

Friction in the actuating mechanismFriction in the release system

ACTUATION:Pedal mechanism, clutch cable,release shaft, master/slavecylinders, hydraulic lines,compressed-air boosterDRIVE TRAIN:Has no effect.

DRIVEN PLATE:Has no effect.PRESSURE PLATE:Has no effect.FLYWHEEL:Has no effect.RELEASE SYSTEM:Wrong release bearing,wrong/no grease used,release shaft, release-shaftbearings worn, damagedguide tubes, release forkbroken or bent

CLUTCH MAKESA N O I S E

QUICK TEST:Locate the source of the noise.Engage/disengage the clutch. Is the noise coming from thevicinity of the clutch?TEST DRIVE:Is the noise still there?

Rotating components are rubbingagainst one another.Loose components

ACTUATION:Pedal mechanism, clutch cable,release shaft, master/slavecylinders, hydraulic linesDRIVE TRAIN: Has no effect.ENGINE: Engine tuning

DRIVEN PLATE:Hub glazed, torsional-vibrationdamper glazed, cover plate on the torsional-vibration damper,torsion springs have broken loose, hub splines wornPRESSURE PLATE:Diaphragm-spring fingers worn,inner surface of diaphragm spring scored due to excessivelylong travel.COIL SPRING CLUTCHES:Cam(s) or release-lever mountings brokenSPIGOT BEARING: NoisyFLYWHEEL: Mating surfaceRELEASE SYSTEM: Release-bearing ball bearings,release-shaft bearings, guidetube, release fork

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G AND SERVICE-TIPS FOR

CLUTCH FAILSTO DISENGAGE

CLUTCH PEDAL ISHEAVY IN OPERATION

G AND SERVICE-TIPS FOR

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L u K C L U T C H S E R V I C ECLUTCH NOT CLEARINGProblem Cause Remedy

Renew the clutch pressure plateCheck straps before fittingRenew clutch pressure plateRenew clutch pressure plate

Straighten driven plate

Clean the facing, remove all signsof corrosionRemove burrs or renew plateRemove all corrosionUse correct grade of greaseCheck parts are correct to applicationCheck parts is correct to applicationRenew driven plate

Check driven plate for correctinstallationRenew bearingCheck suitabilityLubricate snoutRenew bearingReplace clutch cable

Bleed the systemRenew the release systemCheck release system operationClean rust and corrosion fromfacing material

The clutch was droppedDamaged on replacementIncorrect assemblyCover assembly not bolted downevenly and sequentiallyCheck driven plate lateral runout (max 0.5 mm)Vehicle not run for a long period

Damaged spline profileRust on input shaftIncorrect grease usedIncorrect spline profile

Incorrect driven plate

Grease or oil contaminated

Driven plate incorrectly installed

Damaged release bearingIncorrectly matched partsNo grease used

Incorrect clutch cableor adjustment incorrect.Air in the hydraulic systemRelease system damaged

Tangential straps damaged

Damaged levers/spring fingersCover assembly distorted

Driven plate distorted

Corrosion on friction material

Driven plate seized or stickingon gearbox input shaft

Facing too thick

Facing material sticking

Torsion damper broken

Gear box snout damaged

Damaged spigot (pilot) bearingInsufficient release travel

Excessive release travelDriven plate seized to flyheel or to pressure plate

SERVICE IDEAS FOR THE WORLD OF CLUTCHES.

L u K C L U T C H S E R V I C E

CLUTCH SLIPPressure plate overheating

Clutch housing, levers or diaphragmspring brokenDiaphragm fingers worn

Clutch facing worn out

Clutch facing contaminated

Uneven wear pattern on flywheelside of facing materialFlywheel thickness incorrect

Gearbox snout damaged

Clutch cable heavy in operation

Release system heavy in operation

Thermal overloadIncorrect assemblyBroken diaphragm springOil or grease contaminatedIncorrect installation

Excessive release bearing pre-loadNo free play

Normal wear and tearIncorrect pressure plateOilseals leakingGearbox splines overgreasedRelease bearing overlubricatedBadly worn flywheel

Incorrect machining of flywheelBolting surface not machined tosame dimension as running surfaceNon/incorrect lubricantDamaged release bearingIncorrect combination of bearingand snoutClutch cable damagedIncorrect cableDamaged bushes on release armor shaftBushes or bearing not lubricated

Problem Cause RemedyRenew clutch assembly

Renew oil sealFollow correct installation proceduresAdjust pre-loadRenew clutch assemblyAdjust free playRenew clutch assembly

Renew oil sealsRenew clutch assembly

Re-machine flywheel

Machine bolting surface

Renew flywheelRenew gearbox snoutUse correct lubricantCheck parts for suitability

Renew clutch cableCheck for correct cable assyRenew bushes

Lubricate bearings or bushes

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C E T I P S

Incorrect pressure plateDamaged gearbox snout

Release system bearings or bushes wornClutch cable damaged

Release load too greatRelease bearing damagedIncorrect combinationNo grease usedIncorrect grease usedBushes worn or not lubricated

Normal wear and tearIncorrect cable fitted

Fit correct pressure plateRenew release bearingCheck combinationGrease bearing and snoutUse correct grade of greaseRenew bearings and bushesLubricate where requiredRenew cableCheck for suitability

Problem Cause Remedy

The following easy to use charts are provided toenable clutch problems to be easily identified andmake diagnosis simpler

CLUTCH JUDDER

CLUTCH HEAVY IN OPERATION

C E T I P SPressure plate uneven

Facing contaminated with oil

Facings contaminated with grease

Incorrect facing material

Facing dampDifficult or hard operation

Air in the hydraulic system

Damaged gearbox snout

Engine/gearbox mountingsEngine not tuned/misfiring

Broken or bent tangential strapsDistorted coverOil seals defective

Excessive grease on splinesand release bearingIncorrect plate fitted

Moisture penetrated facingClutch cableRelease lever bearingsGearbox snoutMaster or slave cylinderLeaking or damaged master/slave cylinders or pipesIncorrect lubricant used

Incorrect or damaged mountingsCarburettor, fuel injectionignition timing

Replace clutch coverInstall correctlyRenew oil sealsReplace driven plateRenew driven plateRenew release bearingCheck plate is suitable for applicationOperate clutch to remove moistureFully inspect the release systemCheck bearing/snout combinationRenew all suspect parts

Renew any suspect or damagedpartsRenew the snout and use correctgrade of lubricantReplace mountingsCheck engine for correct running

Problem Cause Remedy

Bearing running eccentricallyto diaphragm fingersNo drive

Incorrect driven plate

Torsion damper brokenRelease bearing defectiveSpigot (pilot) bearing defectiveDamaged damper spring breakout

Bearing not centreing

Torsion damper incorrect forvehicles applicationIncorrect damperNot rotating smoothlyBearing seizedIncorrect driving habitsWrong gear selection

Renew bearing

Renew pressure plate or drivenplateFit correct driven plate

Fit correct driven plateRenew bearingRenew bearingRenew driven plate

Problem Cause RemedyCLUTCH NOISE

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LuK-Aftermarket Service oHG

Paul-Ehrlich-Straße 21D-63225 Langen, GermanyPhone: +49 (0) 61 03-753-0Fax: +49 (0) 61 03-753-295

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manual despre kitul de ambreiaj

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