47 replies to this topic

[Jwatts93]

I have a 1989 mini Mayfair with a 1275 metro a engine and it has a pre verto clutch on it I am trying to adjust the clutch as the biting point is basically on the floor and crunches into reverse and hard to get into gear sometimes, I've heard about adjusting the stop bolt , can anyone explain how to do this in a simple way for someone like me who is very new to cars and only had a mini for couple months this is a picture to go by, hope you can help thankyou !!

[Cooperman]

Loosen the 7/16" AF nut which locks the stop bolt in place in the housing.
Pull the arm as far as it will go, by hand, towards the inner wing away from the engine.
Screw the bolt in or out until the gap between bolt head and arm is 0.020". Try the clutch at that and if it's OK lock the nut to hold that position. If the clutch still bites too near the floor undo the bolt a bit more until it bites at the right point. Do the nut up to hold in position.
There are times when the overthrow stops might need to be re-set. The overthrow stop is the big nut in the centre of the 'wok'-shaped clutch cover. This prevents the clutch from being pushed in too far and thus causing damage to the crankshaft thrust bearings. When pushed fully down the inner overthrow nut with the flange on should be against the cover. Don't worry about this at this stage, just set the clutch bite point and come back on here if you have any difficulties.

[bmcecosse]

You may need to go as low as 10 thou gap - but there must BE a gap. Generally I also had to bend the arm slightly towards the slave cylinder.

[Jwatts93]

Ok I will give that a go tomorrow and come back with the results thankyou very much for your help

[Jwatts93]

i have adjusted the clutch as best i can i believe its at 0.011" to 0.012" as i set it at 0.020" and it was worse. but this still hasn't solved the problem it still crunches badly into reverse some of the other gears seem a little smoother but still i don't think this is the problem as its still quite bad when I'm going through the gears it isn't too bad but reverse and first when stationary are sometimes a struggle reverse crunches and first just needs a lot of pressure, it also isn't great going down gears it crunches sometimes
if any one can help me and give me something else to look at that would be much appreciated.
jack

[Jwatts93]

Anyone ?

[Cooperman]

What you need to do, after setting between 0.015" and 0.020" stop clearance is to actually measure the linear distance the top of the arm moves between pedal right up and pedal right down. Hold a steel rule there and measure as accurately as possible. The distance moved must be between 0.50" and 0.60".
I had exactly that with a Mini a while ago and the mechanism seemed to be OK, but I checked on my Cooper 'S' and that was 0.53", so I changed the slave cylinder and the problem was cured with a new movement of 0.58".
I can post a clutch drag fault finder if that would help, although I have already posted it several times. Let me know if you want me to do that.

[Jwatts93]

So turn the engine on put a ruler on the clutch arm then put clutch down and measure the difference when it's put down ? And changing the slave cylinder helped, is this an easy job ? What does it involve, mine looks like it has seen better days to be honest .
Thankyou for your help

[Cooperman]

You don't need the engine running to check the clutch arm movement. Just open the bonnet, get a steel ruler, hold it against the top of the arm and with the ruler held firmly, get someone to push the pedal down ans see exactly how far the top of the arm moves. If it is less than 0.5" there is a problem with the mechanical clutch linkage or the hydraulics. Start by changing the slave cylinder which is about a 30 minute job. You'll need some hydraulic fluid to bleed and top up the clutch hydraulic system. DOT 4 is fine. Slave cylinder bolts are 3/8" UNC, that's 9/16" AF and the clutch flexible needs removing and re-fitting into the new cylinder, ideally with a new copper washer.

[Jwatts93]

What is the clutch flexible ?

[Cooperman]

Because the engine moves slightly, the connection from the clutch cylinder to the clutch slave cylinder has a flexible section, just as the brakes do. If there were no flexible the pipe would eventually fatigue and fail. Just take a look at the slave cylinder and you'll see it coming from the back of the cylinder. It can be a good idea to fit a new flexible hose when changing the cylinder if both are old.

[Jwatts93]

Is this the correct one for my car ?

http://www.minisport...nfo_GSY110.html

[Jwatts93]

And this...

http://www.minisport..._C-AJJ4025.html

[Jwatts93]

And ..

http://www.halfords....tegoryId_255218
Thanks again for your help

[Cooperman]

Yes, yes & yes. But do check the measurement first as if you have a minimum of 0.5" arm movement at the top it's not the slave cylinder and it'll be necessary to look elsewhere.

Here is the clutch diagnostic thing:

CLUTCH DRAG

Clutch drag or failure to engage and/or 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