clutch disengagement problem

[tonypy2]

Having completed an automatic to manual overdrive conversion I'm still trying to iron out a few problems.

I've been having difficulty selecting first or second which was diagnosed as clutch drag - just to give a little backrgound I have the correct bearing carrier fitted, with no wear in the groove, I've turned the fork release pins, fitted a new fork pin, cross shaft bushes and new clevis pins.

By the time I had fitted the exhausts on my back I'd had enough and drove it to my local garage for them to re-fit and seal the exhaust and bleed the clutch again.

The car has come back with great gear selection but I note that they've shimmed the slave cylinder forward with washers - isn't this a ineffective "bodge" - could it also be shortening the life of the release bearing?

I've since investigated the problem further and found quite a bit of play in the hole on the pedal lever that mates to the master cylinder - despite a new clevis pin.  I'm assuming I'll need to remove the pedal box and weld up the hole and drill out again to 5/16, in the hope that this will solve the problem.

Many thanks - any advice would be greatly appreciated.

Tony

[Richard B]

Have you checked the crank thrust washers as well?

Definately remove the free play in the pedal lever.

Are the pedal box bushes worn?

[bobble350]

The slave cylinder should find it's own position, so yes, it's an ineffective bodge. The slave should move out at least 16mm with the pedal fully depressed. If it doesn't you may have air in the system, the plastic pipe could be ballooning under pressure or the wrong master or slave cylinder fitted.
Which hole on the cross shaft lever is the slave connected to? It should be in the middle one. The top hole will give more clutch separation at the cost of a heavier pedal, another bodge.
Were the cross shaft bearings, and security of the fork onto the shaft checked before the box was fitted?

Start by measuring the movement of the slave piston and take it from there.

Mark.

[bobble350]

The slave cylinder should find it's own position, so yes, it's an ineffective bodge. The slave should move out at least 16mm with the pedal fully depressed. If it doesn't you may have air in the system, the plastic pipe could be ballooning under pressure or the wrong master or slave cylinder fitted.
Which hole on the cross shaft lever is the slave connected to? It should be in the middle one. The top hole will give more clutch separation at the cost of a heavier pedal, another bodge.
Were the cross shaft bearings, and security of the fork onto the shaft checked before the box was fitted?

Start by measuring the movement of the slave piston and take it from there.

Mark.

[mikeyb]

slightly off topic, but a decade or so ago, some trader was pushing a modified release bearing carrier to get around "an inherent design problem".  

Can't remember any more about it, what was the problem and what wa the fix - anyone know?

[tonypy2]

Many thanks for the replies so far - I haven't checked the crankshaft end float yet so will have a look at that.  The new bushes completely eliminated play in the cross shaft likewise the pins, I also eliminated any play between the fork and the shaft - the old pin had hair-line cracks in it and was able to flex.  The plastic pipe is new and the push rod is connected to the middle hole.

I'll measure the travel next also I've noticed the slave pushrod is now hard against the release arm, due to the shims and I'm sure this won't be doing the release bearing much good.  I think I'll remove the washers and have another go at bleeding.

Thanks again

Tony

[bobble350]

The modified release bearing is supposed to allow a little eccentricity to stop clutch judder. The early boxes had a short nose piece for the carrier to slide on and it was thought that the carrier was cockling over and hanging up on this. The later long noses can still do it, and one thought is that the clearence to the carrier is too tight and as the grease gets contaminated with clutch dust it binds.
The best way to avoid problems is to accurately locate the gearbox onto the mounting plate with dowels to ensure it is central.

One last thing Tony, you have got the bleed nipple on the slave at the top? The ROM incorrectly shows it at the bottom! The nipple is off the vertical and some advise unbolting the slave and turning to get every last bubble of air out, but I found that this made no difference.

Mark.  

[tonypy2]

Thanks Mark,

It is at the top but I am going to have a stab at bleeding it in the 12:00 position - just to be sure.....

Thanks again

Tony