10 replies to this topic

[rawky]

1991 Mayfair Pre-Verto

Hi Everyone,
Just finished putting the car back together after a clutch rebuild and I have one question, should the revs drop as I put my foot on the clutch pedal? It happens now and I don't want to be wearing down those thrust washers! I adjusted the nut back in until this stopped happening, but now the clutch doesn't disengage.
Is it normal for the revs to drop like this?
Cheers
Rawky

[shorty]

not sure if they should
but i know my revs drop slightly when i dip the clutch

[Pauly]

You've adjusted the throw out too far in, undo the lock nut and wind out the stop. Push the clutch in then wind it back in until it hits the case, release the pedal then put 2 more turns on, that should be roughly right.

(Assistent needed of course )

Paul.

[MRA]

If it stalls then it's too much did you set it by the book ? If so then your thrusts may already have been knackered if this is the case or you suspect it then, if you can get the use of a DTI (Dial Time Indicator or clock, no not off the kitchen wall either ) then gently apply the clutch with the pointer of the clock on the pulley and take a readingmin max will give you the total and this will allow you to ascertain if your thrusts are ok, hopefully they are

[bmcecosse]

I think maybe two FLATS more - not two turns ! Yes - revs will drop when you press the clutch. Main thing is - keep off the clutch as much as possible - don't ever sit at junctions/lights etc in gear with foot on clutch.

[MRA]

definately keep off that clutch........ also don't start it with the clutch pressed as this can wipe all the oil off the thrust bearings

[rawky]

Ok, I understand perfectly. I just wasn't sure whether it is normal that the revs should drop slightly when the clutch is depressed. Seems like it is. Ok cheers fellas.

Rawky

[rawky]

By the way, what does the return stop actually achieve?

Why does a bolt head have to be a certain clearance from the clutch arm, when it never comes into contact with it?

[Ethel]

The throw out stop limits how far the release bearing pushes the clutch so you can stop it pushing against the crank thrust bearings any more than is needed to disengage the clutch.

If it's a pre verto, the return stop allows you to adjust how far the clutch arm returns so it can be set so the release bearing just disengages. If it's set correctly you should be able to pull out the clutch arm by hand until the release bearing makes contact with the clutch cover, creating about a millimeter gap between the arm and bolt head.

[dklawson]

By the way, what does the return stop actually achieve?
Why does a bolt head have to be a certain clearance from the clutch arm, when it never comes into contact with it?

Ethel has answered your question but it sounds like you are focusing on only one of the two adjustments that need to be made on the external pre-verto clutch components. The stop bolt for the arm is nominally set to 0.020" to that bolt head you mentioned. It effects the amount of pedal travel you have before the clutch releases/engages and as stated above, you want it set so the release bearing is not riding all the time on the rotating components.

The other adjustment is on the BIG nut on the end of the clutch cover. That's the one that affects the thrust bearings.

[MRA]

The BIG nuts are 15/16" AF or 22.225mm however you may find that a normal spanner will not fit as the length of said spanner normally means that the jaws are at an angle, you could cut one down or look for a slim spanner, car boot sale and cut it back with a linishing wheel until its the correct thickness...... or you may be lucky and have a thin spanner already

These settings are important for reliability