11 replies to this topic

[flamenco]

Hello all,

I have just replaced the pre-verto clutch on one of my minis, since it was slipping due to oil coming out from the primary gear seal. I have replaced the oil seal, the diaphragm spring, release bearing and clutch plate, all new. I have also set the throw-out stop and throw-in bolt adjustments as suggested in the haynes.

Now my problem is that the clutch is still slipping at high revs, and the biting point is too high, which is what's causing the slipping! I tried to adjust the throw out stop even further in and although the biting point seems to improve slightly, however the clutch pedal will fail to hit the floor, i.e it will not travel all the way down...master cylinder and slave have also been replaced.

Can you please shed some light on this, I have replaced a few clutches before and never had this problem!

Thanks
Jeremy

[MRA]

Did you renew the clutch plunger and arm ?

Also if you release the slave cylinder pushrod from the arm is the arm then free to move, i.e. does it have the small amount of slack required ?

[dklawson]

Are you sure you have the stop-bolt adjustment correct for the long throw-out arm? I believe Haynes calls fro 0.020" between the arm and the head of the bolt. While it can be closer, you want at least a tiny bit of clearance so the throw-out bearing is not riding on the pressure plate spring fingers.

Sorry I cannot offer an obvious solution but I would go through the external adjustments one more time to be sure you haven't missed anything.

[flamenco]

the haynes manual tells you to remove the spring and push the lever outwards before adjusting the clearance...now the lever has a fair amount of slack and therefore must be pushed outwards a fair bit before adjusting...once the bolt is adjusted, the arm weill be again resting on the bolt once the spring is attached again..

[tiger99]

Yes, but with the spring removed, the clearance does need to exist and be small, around 20 thou. A high biting point suggests that it is zero. The throwout stop has nothing to do with that.

[flamenco]

yes, that's what I'm doing...with the spring removed, I am leaving 20thou of clearance between the arm and the bolt...however when the spring is attached, this clearance disappears..

[Cooperman]

Adjust it so that the arm is just touching the stop, undo the overthrow stops to allow unlimited movement. Now measure the linear movement at the top of the arm from pedal right up to pedal right down. The top of the arm MUST move a minimum of 0.50", with a figure of 0.55" being the correct figure. If it moves less, then the problem is either with the hydraulics, slave or master cylinder or air in the system, or there is a problem (unlikely) with the pedal arm to master cylinder piston rod clevis pin. One other unlikely problem is an internal split in the flexible hydraulic hose. If the top of the arm is moving a minimum of 0.5", then it is a mechanical linkage issue, so check for wear in the clevis pin and the ball on the bottom end of the arm. Also check that the arm is not bent as this used to be a common problem before the thicker arms were introduced. The settings must be accurate with a 0.020" gap between arm and stop bolt when the arm is pulled as far as possible towards the inner wing. Only set the overthrow stop when the rest of the linkage is set & working correctly.

[dklawson]

Out of curiousity, did you remove the straps from the flywheel when you fit the new clutch parts?
Was the flywheel resurfaced at the same time that you fit the new clutch parts?

The articles linked below might help.
http://www.minimania...Strap_Alignment
and
http://www.minimania...FAQ__non-Verto_

[The Principal]

did you change the thrust bearing if so did you push it all the way home?

[MRA]

A quick and simple test..

1) remove the arm return spring
2) gently by hand pull the arm in the direction it is meant to go when trying to disengage the clutch, but don't apply any force.
3) now try to turn the plunger, from one side to the other.

Does the arm try to pull itself in and then out as you turn the plunger ? If it does then a new arm and plunger WILL be required.

[flamenco]

hi all, just a quick update.

Yesterday I replaced the clutch arm with a minispares heavy duty one, and adjusted the clearance to 0.020"...but with no success What I could feel was that there was not enough clamping pressure to keep the back plate in contact with the flywheel via the clutch plate...

so, I think there must be something wrong with the diaphram spring assembly...can this problem occur if the bolts have not been tightened up to their correct torque? I wouldn't think that this is the problem..but until I find some time to get the flywheel cover off, I will try and see what could be causing this reduced clamping pressure!

Any ideas?

thanks :)

[flamenco]

Out of curiousity, did you remove the straps from the flywheel when you fit the new clutch parts?
Was the flywheel resurfaced at the same time that you fit the new clutch parts?

The articles linked below might help.
http://www.minimania...Strap_Alignment
and
http://www.minimania...FAQ__non-Verto_

hi Doug :)

no I didn't remove the straps from the flywheel, and neither did I resurface the flywheel...I can only suspect that something is wrong with the diaphram or the bolts holding it to the back plate!