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China 中文 | English
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SACHS useful tip:

Clutch does not disengage.

Excessive lateral runout of clutch disk

Cause:

  • Deformation during transport or installation
  • Lateral runout of approx. 0.5 mm exceeded

Consequence:

  • The specific lift on the pressure plate is no longer sufficient to ensure full disengagement

Comment:

Always check clutch disks for lateral runout before installation.

Excessive lateral runout of clutch disk

Cause:

  • Deformation during transport or installation
  • Lateral runout of approx. 0.5 mm exceeded

Consequence:

  • The specific lift on the pressure plate is no longer sufficient to ensure full disengagement

Comment:

Always check clutch disks for lateral runout before installation.

Fretting corrosion on hub spline

Cause:

  • Lubrication instructions not followed during installation

Consequence:

  • Clutch disk fails to slide freely on transmission shaft, jams. Clutch facing still contacts friction surface on flywheel. Clutch grab may be noticeable in early stages.

Comment:

Always use high-performance lubricant, SACHS no. 4200 080 050.

Fretting corrosion on hub spline

Cause:

  • Lubrication instructions not followed during installation

Consequence:

  • Clutch disk fails to slide freely on transmission shaft, jams. Clutch facing still contacts friction surface on flywheel. Clutch grab may be noticeable in early stages.

Comment:

Always use high-performance lubricant, SACHS no. 4200 080 050.

Hub spline damaged

Cause:

  • Transmission shaft and clutch hub forced together during installation

Consequence:

  • Clutch disk jams instead of slides on transmission shaft.

Comment:

Center the clutch disk - using the right tools - during installation!

Insert the transmission shaft carefully

Hub spline damaged

Cause:

  • Transmission shaft and clutch hub forced together during installation

Consequence:

  • Clutch disk jams instead of slides on transmission shaft.

Comment:

Center the clutch disk - using the right tools - during installation!

Insert the transmission shaft carefully

Clutch disk "dished" (arched)

Cause:

  • Transmission shaft jammed against clutch disk hub during installation.
  • Deformation due to severe overheating (blue discoloration of steel components).

Consequence:

  • Prescribed lift on pressure plate is no longer sufficient to smoothly disengage clutch.

Comment:

Also causes drag due to insufficient lift on pressure plate.

Clutch disk "dished" (arched)

Cause:

  • Transmission shaft jammed against clutch disk hub during installation.
  • Deformation due to severe overheating (blue discoloration of steel components).

Consequence:

  • Prescribed lift on pressure plate is no longer sufficient to smoothly disengage clutch.

Comment:

Also causes drag due to insufficient lift on pressure plate.

Interfacing springs or driving plate fractured

Cause:

  • Engine or transmission dropped with the transmission shaft still in the clutch disk hub. Fracture caused by lever effect
  • Parallel or angular deviation

Consequence:

  • Excessive lateral runout of clutch disk.

Interfacing springs or driving plate fractured

Cause:

  • Engine or transmission dropped with the transmission shaft still in the clutch disk hub. Fracture caused by lever effect
  • Parallel or angular deviation

Consequence:

  • Excessive lateral runout of clutch disk.

Hub spline worn / burr formation

Cause:

  • Clutch housing and crankcase flange not centered, wobble motion due to angular or parallel deviation
  • Pilot bearing missing
  • Transmission input shaft has excessive play or is not guided

Consequence:

  • Hub jammed or tilted on transmission input shaft

Comment:

Can also cause noise.

Hub spline worn / burr formation

Cause:

  • Clutch housing and crankcase flange not centered, wobble motion due to angular or parallel deviation
  • Pilot bearing missing
  • Transmission input shaft has excessive play or is not guided

Consequence:

  • Hub jammed or tilted on transmission input shaft

Comment:

Can also cause noise.

Excessive roll speed / burst facings

Cause:

  • Driving at high roll speeds in low gear with the clutch pedal depressed, clutch disk exceeds burst speed
  • Selecting the wrong (too low) gear when downshifting

Consequence:

  • Facing debris gets stuck in the flywheel or in the clutch pressure plate housing.

Comment:

The engine is not involved at all! Facing burst speed is around 1.7 to 2 times higher than the maximum engine rpm. Overheated facings may burst earlier.

Excessive roll speed / burst facings

Cause:

  • Driving at high roll speeds in low gear with the clutch pedal depressed, clutch disk exceeds burst speed
  • Selecting the wrong (too low) gear when downshifting

Consequence:

  • Facing debris gets stuck in the flywheel or in the clutch pressure plate housing.

Comment:

The engine is not involved at all! Facing burst speed is around 1.7 to 2 times higher than the maximum engine rpm. Overheated facings may burst earlier.

Torsional damper destroyed by overloading

Cause:

  • Low-revving driving style. Driving in high gear at low speed and full throttle.
  • Extreme irregular engine operation
  • Worn joints in the driveline

Consequence:

  • Fragments are thrown outwards and get stuck in the facings.

Torsional damper destroyed by overloading

Cause:

  • Low-revving driving style. Driving in high gear at low speed and full throttle.
  • Extreme irregular engine operation
  • Worn joints in the driveline

Consequence:

  • Fragments are thrown outwards and get stuck in the facings.

Tangential leaf springs bent or deformed

Cause:

  • Extreme thrust load due to incorrect shifting
  • Improper towing maneuvers
  • Operational errors on the roller test stand
  • Play in the driveline
  • Deformation during installation

Consequence:

Insufficient pressure plate lift.

Tangential leaf springs bent or deformed

Cause:

  • Extreme thrust load due to incorrect shifting
  • Improper towing maneuvers
  • Operational errors on the roller test stand
  • Play in the driveline
  • Deformation during installation

Consequence:

Insufficient pressure plate lift.

Diaphragm spring contacts torsional damper during release

Cause:

  • Permissible release travel exceeded
  • Incorrect disk installed

Consequence:

  • Diaphragm spring drives clutch disk

Comment:

Also causes noise

Diaphragm spring contacts torsional damper during release

Cause:

  • Permissible release travel exceeded
  • Incorrect disk installed

Consequence:

  • Diaphragm spring drives clutch disk

Comment:

Also causes noise

Diaphragm spring tips / release levers ground off

Cause:

  • Guide tube for the clutch release bearing bent
  • Engine / transmission not correctly centered

Consequence:

  • Continuous off-center clutch release bearing contact with the diaphragm spring tips exceeding the self-centering capacity will cause relative motion and therefore wear. This also applies to the release levers.

Diaphragm spring tips / release levers ground off

Cause:

  • Guide tube for the clutch release bearing bent
  • Engine / transmission not correctly centered

Consequence:

  • Continuous off-center clutch release bearing contact with the diaphragm spring tips exceeding the self-centering capacity will cause relative motion and therefore wear. This also applies to the release levers.

Pressure plate fractured / extreme overheating

Cause:

  • Clutch permitted to slip constantly
  • Insufficient clamp force
  • Problems with the release system, e.g. stiffness or lack of clutch play
  • Contamination with oil or grease
  • Excessive flywheel thickness

Consequence:

  • Insufficient pressure plate lift.

Pressure plate fractured / extreme overheating

Cause:

  • Clutch permitted to slip constantly
  • Insufficient clamp force
  • Problems with the release system, e.g. stiffness or lack of clutch play
  • Contamination with oil or grease
  • Excessive flywheel thickness

Consequence:

  • Insufficient pressure plate lift.

End plate deformed (MX clutch pressure plates – VW, Audi, Seat, Skoda)

Cause:

  • Incorrect clutch pressure plate installed
  • End plate / clutch pressure plate incorrectly positioned relative to locating pins on flywheel

Consequence:

  • Housing deformed such that pressure plate has insufficient lift.

End plate deformed (MX clutch pressure plates – VW, Audi, Seat, Skoda)

Cause:

  • Incorrect clutch pressure plate installed
  • End plate / clutch pressure plate incorrectly positioned relative to locating pins on flywheel

Consequence:

  • Housing deformed such that pressure plate has insufficient lift.

Preliminary damper completely destroyed

  • Cause:
  • Transmission shaft jammed against clutch disk hub during installation.

Consequence:

  • Serious damage leading to component failure.

Comment:

Multi-step torsional damping mechanisms have a complex, almost delicate structure. Handle with the utmost care during installation.

Preliminary damper completely destroyed

  • Cause:
  • Transmission shaft jammed against clutch disk hub during installation.

Consequence:

  • Serious damage leading to component failure.

Comment:

Multi-step torsional damping mechanisms have a complex, almost delicate structure. Handle with the utmost care during installation.

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