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Calder Clutch Fitting help page

Clutch fitting Advice (important please read)


  1. Always ensure vehicle and heavy parts are securely supported and cannot trap hit or crush you.
  2. Always ensure battery is disconnected to prevent short circuits and fires.

    Removal of clutch

  1. Make a note of which side of centre plate is the flywheel side.

    Cleaning and inspection

  1. After removing clutch, thoroughly clean bell-housing, flywheel, primary shaft and all surrounding areas and parts to ensure there will be no contamination to clutch lining or mating friction surfaces. (Failing to do this will cause clutch judder; asbestos free linings are significantly harder than asbestos ones and will not work correctly with any contamination).
  2. Inspect flywheel for heat crazing, grooves, or hotspots if any found machine or replace flywheel (as asbestos free linings are significantly harder than asbestos ones and will not bed in).
  3. Inspect all the linkages and parts to make sure they are not worn or damaged.
  4. With clean hands make sure the clutch cover fits the flywheel.
  5. With clean hands inspect clutch plate making sure that the centre plate can slide freely on its primary shaft and the shaft is not worn (as this may course centre plate to not be effective in its movement i.e. clutch not clearing).
  6. Inspect the release bearing making sure it can slide freely on its shaft and that the shaft is not worn (as this may cause release bearing to not be effective in its movement i.e. clutch not clearing or not possible to depress clutch pedal and also could cause clutch to be held in released position).


  1. We always recommend that hub spline and bearing carrier is lubricated sparingly applying lithium grease using a loaded toothbrush reserved specifically for this purpose.  Excess grease will cause premature failure through clutch drag, judder or slip. Friction material and grease do not mix. Copper based grease should not be used because copper particles damage ball races and thrust surfaces in the release bearing.
  2. Clutch plate has to be centralized with a tool when fitting clutch. (Failure to do this causes damage to the centre plate resulting in the clutch not working at all or impossible to fit gearbox).
  3. The Gear box should be supported and lined up correctly. Hanging the gear box on centre plate will result in the centre plate being bent or spline damage (clutch not clearing and difficult to fit gearbox).
  4. The Gear box should be left in gear so you can turn the primary shaft from outside the bell housing to line up the spline on the primary shaft with centre plate spline.

Driving Practice (please advise your customer)

The clutch is designed to engage/disengage drive

1.  not for racing starts (the clutch is the safest and weakest part on the drive train to fail and will do so if       over loaded).

2. Not for holding the vehicle on hills (the clutch does not have a large heat sink and will over heat causing

     loss of frictional value to lining and even total destruction of all clutch parts.

3.     Not for excessive tow or bump starts and changing in to too lower gear ( the clutch is designed to give drive one way excessive tow or bump starts and changing in to too lower gear will cause drive straps on clutch cover to buckle resulting in clutch not clearing or clutch cover drive straps to brake.

    Concentric slave cylinders must be fitted correctly

 It is recommended that :-
1. Fluid must be completely cleaned and flushed out as any dirt bled into cylinder will damage seals.
2. Cylinder mounting surface on gearbox must be clean and free from damage this can cause rear cylinder     seal not to be clamped correctly and leak especially on cylinders that fit into a recess as some Vaxhalls     do, if fitted cockled this courses excessive wear and load on one side of the cylinder also making it fail. If     its fitted cock eyed it will fail, it takes some mechanics 3 times/ cockups to learn and get it right, do not     tighten one bolt up and then the next this will make it cock eyed, then the plate and seal on the back will     not be clamped and will leak or the seal inside gets overloaded on one side and rips.  
3. Incorrect bleeding with Concentric slave cylinders, you can only press the peddle once per release if the     peddle is pressed twice or more it can over pressure the cylinder making seals fail or causing casing to     fail.