Clutch engage point changes

[Gio]

The problem is that (and has been for three and a bit years) the bite point on the clutch pedal occasionally changes. Not gradually, just suddenly it moves a couple of inches down the pedal travel. Still works fine and everything. Then some time later (could be days or minutes), there's a change in the feeling of the pedal and the clutch bite is backwhere it was.

Today it happened again - and the bite point was suddenly about half an inch above the pedal so the clutch never fully engaged. Would drive around fine but if I floored it, slippy slippy slippy.

And this comes after the clutch was replaced in 2001 and the clutch master cylinder was replaced two months ago. Both by the same Nelson. And it did this strange "first one position then the other" behaviour from the off anyway.

Anyone had anything similar or is it just my fault for having a very old Series 1 silver Zed?

And after parking the car up for 2 hours, everything went back to normal. Clutch bite point where it was and no probs.
TIA - Gio

 

[Mr.F]

The bite point of a clutch should be a purely mechanical thing - to have it change itself around like this is strange! Several thoughts come to mind:
1. the pivot ball for the release arm is known to break on Z32s, but normally this would lead to terminal inability to use the clutch release. Possibly the lever is moving relative to the ball, but still confined by the spring so that it does not completely unseat.
2. the intervention of servo assistance on the clutch pedal may have an effect - are there any signs of leakage on the servo vacuum hoses or the reservoir bottle and tank. This may give a variable servo assistance effect? Also, the check valve in the vacuum line may be faulty.
3. if the clutch servo has ever been removed and stored wrongly, knocked or dropped, then the reaction disc may be displaced giving a different clutch pedal reaction.....
4. a piston may be sticking intermittently in the master cylinder or the slave cylinder?

Please let us know the outcome to add to our knowledge of the strange faults that Z32s are capable of generating.