Clutch fails to disengage

The following easy to use charts are provided to enable clutch problems to be easily identified and make diagnosis simpler.

Problem	Cause	Remedy
Tangential straps damaged	The clutch was dropped Damaged on replacement	Renew the clutch pressure plate, Check straps before fitting
Damaged levers/spring fingers	Incorrect assembly	Renew clutch pressure plate
Cover assembly distorted	Cover assembly not bolted down evenly and sequentially	Renew clutch pressure plate
Driven plate distorted	Check driven plate lateral runout (max 0.5 mm)	Straighten driven plate
Corrosion on friction material	Vehicle not run for a long period	Clean the facing, remove all signs of corrosion
Driven plate seized or sticking on gearbox input shaft	Damaged spline profile, Rust on input shaft, Incorrect grease used, Incorrect spline profile	Remove burrs or renew plate, Remove all corrosion, Use correct grade of grease, Check parts are correct to application
Facing too thick	Incorrect driven plate	Check parts is correct to application
Facing material sticking	Grease or oil contaminated	Renew driven plate
Torsion damper broken	Driven plate incorrectly installed	Check driven plate for correct installation
Gearbox snout damaged	Damaged release bearing, Incorrectly matched parts, No grease used	Renew bearing, Check suitability, Lubricate snout
Damaged spigot (pilot) bearing	Worn	Renew bearing
Insufficient release travel	Incorrect clutch cable or adjustment incorrect. Air in the hydraulic system Release system damaged	Replace clutch cable Bleed the system Renew the release system
Excessive release travel		Check release system operation
Driven plate seized to flywheel or to pressure plate		Clean rust and corrosion from facing material

1. Worn diaphragm spring fingers

Cause 

• Release bearing seized

• Faulty release bearing

• Incorrectly adjusted release system

2. Broken clutch levers

Cause 

• Release bearing running off centre

• Incorrectly adjusted release bearing

• Release lever bushes worn

3. Damaged inner bore on release bearing

Cause 

• Incorrect grade of grease or no grease used

• Damaged gearbox snout

4. Damaged bearing lugs

Cause 

• Damaged release system

5. Broken pressure plate

Cause 

• Overheated pressure plate as a result of prolonged clutch slip

• Clutch slips due to worn facings

• Damage or seized release system

• Faulty slave cylinder

• Facings oil contaminated

(replace faulty seals)

6. Clutch cover damaged

Cause 

• Incorrect fitting

-> Not aligned to flywheel correctly

7. Gearbox snout worn

Cause 

• Incorrect grade of grease or no grease used

• Damaged release bearing

8. Clutch cover damaged (VW)

Cause 

• Incorrect fitting

• Not aligned to flywheel correctly

9. Damaged bolt holes

Cause 

• Incorrect fitting

-> Reinforcing plate not fitted

10. Fouling marks on driven plate segment rivets (VW, Rover)

Cause 

• Incorrect fitting

-> Release clip incorrectly fitted

• Incorrect circlip

11. Tangential strap broken

Cause 

• Play in the drive train

-> Worn drive line coupling (BMW)

• Incorrect driven practice

-> Tow starting in 1st or 2nd gear

• Wrong clutch fitted

-> Engine rotation incorrect (Renault)

12. Tangential strap bent

Cause 

• Play in the drive train

-> Worn drive line coupling (BMW)

• Incorrect driven practice

-> Tow starting in 1st or 2nd gear

-> Incorrect gear selection

• Improper storage

-> Dropping the clutch prior to fitting

• Clutch not bolted up evenly and sequentially

13. Damaged spline profile

Cause 

• Incorrect fitting

-> Gearbox input shaft and hub splines not correctly aligned prior to fitting

-> Driven plate not centered

• Incorrect driven plate

14. Rust and corrosion on the hub splines

Cause 

• Gearbox input shaft not greased

15. Splines are damaged on one side and worn to a taper, torsion damper damaged

Cause 

• Spigot (pilot) bearing defective

• Misalignment between engine and gearbox

16. Damaged idle damper

Cause 

• Incorrect fitting

• Incorrect driven plate

17. Backing plate distorted

Cause 

• Incorrect fitting

-> Gearbox input shaft and hub splines were not correctly aligned

18. Driven plate segments sheared

Cause 

• Worn or missing spigot (pilot) bearing

• Misalignment condition between engine and gearbox

• Gearbox hung while fitting the clutch

19. Burst facing

Cause 

• Driven plate speed exceeded the burst 

speed of facing material. The clutch has 

been disengaged while travelling at a speed

above the maximum speed for the gear 

selected.

The damage is caused independently of 

engine speed, the critical factor is the speed 

of the gearbox input shaft.

20. Facing burnt

Cause 

• Oil contaminated facings

-> Faulty oil seals

• Release system seized or faulty

• If the flywheel has been refaced the pot 

depth was not considered or the bolting 

surface not machined by the same amount

21. Excessive driven plate runout
(distorted driven plate)

Cause 

• Driven plate not checked befor fitting

-> Driven plate bent during fitting
(maximum permissible runout 0.5 mm)

22. Bearing and casing damaged

Cause 

• Overheating of the release bearing due to

incorrect clearance causing loss of grease 

and resulting in the bearing breaking up

23. Bearing carrier damaged

Cause 

• Release bearing seized on gearbox snout

• Damaged gearbox snout

• Worn or damaged release arm bushes

24. Release bearing worn and damaged

Cause 

• Incorrect adjustment of release arm

• Insufficient preload on bearing
(specification 80 – 100 N)