12 replies to this topic

[mini-me91]

Iv recently rebuilt an 850 engine which i fitted into my car last weekend, it took me a while to sort all the little problems out so got it running yesterday afternoon and found that i cannot get any gears, iv tried adjusting the stop with little success, i loosened the big nuts on the clutch arm first obviously as these would stop the arm moving freely. I managed to get 3rd and 4th when i put the stop fully out but not first and second, when the stop is undone as far as it will go the pedal stops, about 3/4 of the way down. so i screwed to bolt back into the housing, then when the pedal was pressed to the floor, it was slowing the engine down, anyone know what may be wrong with it?

[mini-me91]

Iv now tried various things to solve this with no luck. Iv had the clutch out checked everything on it, extended the pin into the slave cylinder and fitted a new slave. But it still doesnt work. If you press the pedal it feels like the clutch is working but it cant be as im still unable to get any gears. Iv asked a few mechanics and even they dont know whats causing it, does anyone have any ideas?

[Guess-Works.com]

Can you select gears when the engine is switched off ?

[mini-me91]

Yes thats not a problem, just cant at all when the engine is running

[Guess-Works.com]

Rules out the gearbox then...

Have you set the adjustment screw correctly, by removing the return spring, bring the arm out so that the clutch release bearing is in contact with the clutch, unscrew the adjustment screw so that it meets the arm, and then turn back one half turn ?

[mini-me91]

yes iv tried that but it still didnt work. I have even tried pulling the arm out with a crowbar but the arm hits a stop inside the casing and wont move any further. At first i thought the clutch was the wrong way around but that wasnt the problem either. I have also changed the flywheel cover and the clutch arm twice

[Ethel]

Apologies if these seem insulting questions...

Are all the clutch parts matching, it's not a pre verto clutch arm on a verto clutch?
Primary gear isn't seized on the crank?
Crank endfloat not excessive?

[JordanGT]

The clutch arm ball on the end of the release bearing is not broken or worn. I was struggling with my clutch, it was dragging and slipping. I changed the arm and the push rod and all the clevis pins and then reset all the clearances as per the Haynes Manual,bled all the system again and now all is fine.

[Cooperman]

Here is the 'fault-finder' for clutch drag:

CLUTCH DRAG

Clutch drag or failure to disengage is not an uncommon problem with the Mini.
There are several possible causes as follows:

A. HYDRAULIC SYSTEM
1. Wear in the pedal spindle or failure of the pedal to master cylinder clevis pin.
2. Failure of seals in the clutch master cylinder.
3. ‘Ballooning’ of flexible hose due to internal hose degradation or damage
4. Air in system due to inadequate bleeding
5. Failure of slave cylinder seals

B. MECHANICAL SYSTEM – WITHDRAWAL MECHANISM
1. Wear in top clevis pin
2. Wear in lower clevis pin
3. Bent arm
4. Worn or broken ball at lower end of arm where it engages into plunger.
5. Wear in plunger ball seat.
6. Incorrect setting of overthrow stop nuts
7. Incorrect setting of adjusting screw (pre-Verto)
8. Corrosion between plunger and clutch cover due to lack of lubrication.
9. Thrust bearing failure – accompanied by a lot of noise.

C. THE CLUTCH ASSEMBLY
1. Failure of clutch diaphragm spring due to fatigue or distortion
2. Centre plate hub not sliding on primary gear splines.
3. Clutch plate surface de-laminating or breaking up
4. Distorted clutch plate.
5. If fitted, clutch plate shock springs broken and causing a ‘jam’.
6. Primary gear not rotating freely on crankshaft due to either: i) Insufficient primary gear end float,
ii) Primary gear bushes seizing on crankshaft, or, iii) Primary gear bushes breaking up

[mini-me91]

Iv solved the problem now. I took the starter off to make sure the pressure plate was moving and was only moving about 1mm, so i changed the clutch cover to see if that improved it, it did move the pressure plate a bit more; so i took the clutch arm off and found it was worn but not excessively, so changed the arm and bottom clevis just to elimate them. This paid off as the pressure plate moved much further then, im shocked by the amount of problems that was caused by these parts being worn. Thank you for all your help guys i really appreciate it :)

[Cooperman]

Loss of a very small amount of travel anywhere in the clutch linkage can cause that sort of clutch drag.

[mini-me91]

The wear was that small i didnt think it was an issue but lesson learnt ;)

[JordanGT]

Glad you found it, yeah that small amount of wear causes a whole world of heart ache and pain. When I looked at the ball on the bottom of my arm against a brand new one you could clearly see the differences.