Indicator:

No dis-engagement

Cause:

Clutch brake not operating (Pull-Type Commercial Clutch)

Effect:

1. Worn cross shafts
2. Worn cross shaft bushes in bellhousing
3. Worn or damaged clutch fork
4. Excessive wear on release bearing housing

Action:

1. Replace clutch kit
2. Replace cross shafts
3. Replace cross shaft bushes

» Link to Guide

Indicator:

Unable to dis-engage the clutch

Cause:

1. Improper driving practice.
2. Sudden down changing of gears i.e. 5th gear to 2nd gear.
3. Constant “dropping” of clutch at extremely high RPM when taking off.

4. Poor handling/shipping practises

Effect:

Bent drive/lifting straps

Action:

1. Renew clutch kit
2. Driver education

» Link to Guide

Indicator:

Slipping/Poor clutch performance

Cause:

1. Excessive heat caused the pressure plate surface fatigue.

2. Only replaced the clutch disc and pressure plate was not assessed.

Effect:

Warped clutch cover pressure plate assembly

Action:

1. Replace the clutch kit

» Link to Guide

Indicator:

No gear selection/difficult engagement

Cause:

Retractor clip has become dislodged/stretched

Action:

1. Over adjustment of clutch has caused the stretching of the retractor clip
2. The pressure plate has been dropped
3. The pressure plate has been damaged in transit

Action:

1. Replace clutch cover
2. Inspect the clutch operating adjustments
3. Always practice safe handling of the cover when fitting
4. Inspect the clutch cover prior to fitment to ensure there are no retractor clip issues.

» Link to Guide

Indicator:

Slipping clutch/Engagement and Dis-Engagement Problems

Cause:

1. Bell housing has not been degreased and cleaned. Poor installation of the new clutch. The new clutch disc has not worn but fibres have become lodged in the new clutch cover are that of the previously worn clutch. It is a requirement due to ventilation designs that the bell housing area free from old fibres, dirt and grease when installing new clutch.
2. This problem is common in 4 wheel drive vehicles when an inspection cover or a clutch fork cover boot has not been Inspected for re-use or replaced when installing a new clutch.

Effect: 

Worn clutch disc facing fibres and/or dirt lodged between diaphragm spring and clutch cover housing causing loss of cover clamping force.

Action:

1. Ensure the bell housing and back of the engine are thoroughly degreased and cleaned of foreign material before installing a new clutch.
2. Ensure inspection locations are sealed correctly with any boots thoroughly inspected for re-use and if necessary replaced. (Note: These problems are common on farm vehicles, vehicles travelling on sand and 4x4 recreational vehicles.)

» Link to Guide

Indicator:

Slipping/Shudder, Poor clutch performance

Cause:

1. Overloading the clutch
2. Overloading the vehicle
3. Incorrect clutch free travel
4. Clutch control failure (Hydraulic/Cable)
5. Driver error

Effect:

Pressure plate casting has heat deterioration.

Action:

1. Replace clutch kit and machine flywheel
2. Check clutch control mechanisms and if necessary repair or replace
3. Driver education

» Link to Guide

Indicator:

Non-Release (Clutch Drag)/Pedal Vibration

Cause:

1. Poor fitting practices (lever strut has become dislodged when fitting)
2. Clutch lever fatigue due to incorrect free travel

Effect:

Release lever plate uneven (when bolted to the flywheel)

Action:

1. Replace clutch kit
2. Check clutch control system and repair or replace if necessary
3. Check and adjust clutch free travel

» Link to Guide

Indicator:

No gear selection/difficult dis-engagement.

Cause:

Stretched and damaged retractor clip (Clip stretched above diaphragm).

Effect:

After installation of new clutch, unable to select gear.

Action:

1. Fit new cover assembly
2. Adjust clutch to manufacturer’s specifications.
3. Always check components before fitting and ensure that the tip of retractor clip is resting on top of the diaphragm.

» Link to Guide

Indicator:

Difficult to engage/disengage gear, grating noise and hard pedal at the end of the operating stroke.

Cause:

1. Flywheel depth or step incorrect
2. Clutch thrust bearing has fallen off the gearbox nose cone slide.
3. Clutch disc too thick
4. Incorrect clutch free travel (too much pre-load)
5. Faulty clutch hydraulics

Effect:

Diaphragm fouled on clutch disc. Crashing in gear and unable to obtain clutch adjustment.

Action:

1. Check flywheel depth or step incorrect
2. Check for wear or damage to the gearbox nose cone slide
3. Check clutch disc thickness
4. Check clutch hydraulics and replace if necessary
5. Adjust clutch free travel to manufacturers specifications

​

» Link to Guide