Clutch adjustment gone weird - now ok

[Melodyk]

The clutch disengages when you press the pedal halfway down but if you fully depress the pedal then it won't disengage and you can't get any gears. So it's over-travelling and the splines in the clutch are going over centre. But all the hydraulics seem fine and the release arm adjustment is 2mm as per manual. We have bled it a few times. We've even had the engine out and looked at the clutch itself and it is fine. What else can we check?

[jimj]

I had exactly this problem with a new clutch but in an S3 with the Voight 5 speed Sierra box which is a bit different. Much faffing and adjusting made no real difference but a half inch block of wood, painted black of course, screwed to the bulkhead under the pedal prevented the pedal being pressed too far.
It sounds a bit crude but has worked perfectly over the last 10,000 miles or so.
Jim

[Melodyk]

That sounds like a typical Lotus workaround. Was that from the technical bulletin!

[mbell]

If it's a plus 2 there an adjustable clutch stop (aka a bolt) built in to the pedal box.

[Melodyk]

Checked and reassembled master cylinder and it appeared to fix the problem. Clutch pedal then worked as normal and you had full travel for usual operation. Drove about 10 miles to test and it gradually changed back to how it was before. Full pedal travel won't work and half travel lets you change gear ok. So it's not a pedal travel issue. It seems to be to do with the hydraulics.

[mbell]

Have you checked the diameter of master/ slave?

Master should be 5/8" and think slave is 7/8.

[Melodyk]

Yes we have the right master and slave cylinder and braided pipe. The whole set up was working ok previously. We had the engine and gearbox out to replace a gearbox seal and then put it all back together with same bits. It was left standing for nearly a year due to getting fed up with it. Not sure why it won't work now it's gone back together with same bits though.

[Certified Lotus]

Have you checked the length of the rod in the master cylinder? The length of this rod is critical to the correct operation.

[Melodyk]

We haven't changed the master cylinder so it's the same rod and was working ok previously. It worked fine again this morning too and then went back to being wrong again.

[Craven]

Does the point in the pedal travel when the clutch just engages change under fault conditions ?

[Melodyk]

Yes it does. When you have to fully depress the pedal then just as you raise your foot it starts to bite. When it goes wrong and you need only half press the pedal then the clutch comes in slightly above that. So it's completely different. If you fully depress the clutch in this situation then it's as if you haven't declutched at all and you cannot select a gear.

[Craven]

Check the slave pushrod for location in the arm and the return spring. Possible the pedal / master clevis position changing.
Ron.

[prezoom]

This probably will not make you happy, but it may be time to take a look at the throw out bearing and the spring clips that hold it to the lever arm.

[gjz30075]

Possibly a crack in the fork arm?

[oldelanman]

Have you checked if you still have clearance at the slave cylinder pushrod when the fault occurs ? Sounds to me like the release arm may not be returning fully when the clutch pedal is released, possibly due to a sticking slave cylinder piston and/or a weak/missing return spring.
If you haven't done so already it may help to jack the car up and observe what's going on with the release lever while someone operates the clutch repeatedly.