Technical Answers to your Questions
Causes of Clutch Disc Failure
The diagnosis as per below applies to all clutch applications.
These diagnostic comments are based on the premise that the flywheels are Ground and Machined to OE specifications. If the flywheel has not been machined when fitting a new clutch it is a given fact that premature clutch failure WILL OCCUR . Also it assumes that the clutch releasing systems are in perfect operational condition. If not these components must be replaced or repaired to OE standard.
Causes of Clutch Disc Damage Burst or Broken Facings.
Burst or broken clutch driven plate facings are caused by overstraining of the facing Matrix due to incorrect driving practice or incorrect clutch installation proceedure including adjustments, or flywheel damage.
- Incorrect gear selection of a low gear while driving at speed causes the driven plate to accelerate instantaneously to a speed far in excess of the facing burst strength due to the multiplication of the rotation speeds of the Gearbox and or Differential Ratios. The driven plate rotation
speed is independent of the engine speed.
- The clutch disc exceeds its facing burst speed limit while the clutch is disengaged for gear selection, and when the clutch is re-engaged the facing can disintegrate completely. The Facing material becomes entwined and bound amongst the Pressure Plate (cover assembly)
componentry and restricts the correct operation of the Clutch cover and its components.
It is not possible for the driven plate material to disintegrate while it is firmly clamped between the pressure plate and the flywheel.
Disintegration can only occur while a clutch is disengaged or slipping due to do faulty adjustment proceedure during installation.
- Mis-Shifting a gear while driving at speed can also cause the plate to accelerate past its facing burst strength as per the previous paragraphs 1 & 2.
- Tow-Starting or push starting a vehicle while in low Gear can cause increased rotation of the driven disc and also cause the facing material to tear away from the clutch backing plates when the clutch is suddenly engaged.
- Repeated harsh clutch engagement at high engine RPM can also cause the facing material to break away from the Backing plate or damage the clutch hub the stop pins-and blow out the compression springs causing compete clutch disc failure.
- Excessive clutch slippage while driving causes the facing materials to overheat resulting in disintegration and failure of Clutch Disc and Pressure plate assemblies due to contamination from the facing materials.
- Simply dropping a clutch disc on the floor prior to or during installation can impact and easily crack the facing material after a short operational period.
- Fitting a clutch to a vehicle which has had an engine performance modification which exceeds the designed torque ratings of the clutch and Clamp loading of the pressure plate will also cause Premature clutch failure.
Because the Clutch Pressure plate (Cover Assembly) is less efficient than the Flywheel as a Heat Sink the Cover side linings operating temperatures will be greater and that particular lining will be more likely to carbonize, become brittle and BURST from excessive heat damage.
Also excessive application of spline grease can spin across the clutch hub and contaminate the facings to become permanently damaged causing the clutch to slip and or shudder.