Clutch problem

[Buzby58]

I have a '69 2 door saloon with a 1275 engine and box fitted with a hydraulic clutch.

The clutch pedal has always needed to be pressed right down to the floor and has finally given up making me think it's a hydraulic problem.

Looking at the condition of the master and slave cylinders I've replaced them both and bled the system through. It has made absolutely no difference.

Any recommendations as to where to look next?

[bmcecosse]

It has likely run out of travel..... The mechanism may not have been withdrawing the clutch fully -and if it had a carbon thrust bearing fitted - that may have worn away. I believe it is usual to fit a 'roller' thrust when using the hydraulic mechanism. You will really have to go under and observe the movement of the lever when someone floors the pedal - and decide if it has come to the end of travel - or can it be adjusted to move further.....

[Buzby58]

What I suspected and didn't really want to hear

Would it be easier to remove engine and 'box as one or wiggle out the box on it's own?

[bmcecosse]

Always much easier to take the engine out (or just slide it forward on a trolley jack) and leave the box in place!

[IslipMinor]

With a hydraulic clutch there should not be return spring between the end of the clutch release arm and the engine back plate. If there is, remove it and depress the clutch pedal a few times to allow the slave cylinder to take up the slack - it's part of the self-adjusting mechanism.

Clutches are notoriously awkward to bleed - are you sure that you have removed all the air? Assuming there is no return spring as above, make sure there is enough room in the master cylinder reservoir for some extra fluid and push the rod in the slave cylinder all the way back into the slave cylinder bore. Again depress the clutch pedal fully a few times and repeat.

Another trick is to bleed the system backwards, but you need a pressurised bleed kit to do that.

[bmcecosse]

Why no return spring Richard?? Surely if no spring the carbon will be constantly touching the pressure pad? The Mini system has a return spring - BUT it also has a return stop, so the clutch release bearing is drawn clear, but only just clear (when the stop is correctly adjusted - which is not often judging by the mini forum posts...). So - I'm guessing the Minor hydraulic doesn't have a stop - and so what keeps the carbon off the pad?? Just the natural 'run out' of the pressure assembly?

[IslipMinor]

If it uses the standard Midget type slave cylinder, which would be the obvious thing, the push rod is a fixed length, with no means of adjustment. The adjustment is a continuous take up of free play by a light spring inside the slave cylinder. Yes it means that the carbon thrust is lightly rubbing on the clutch pressure plate.

The design is very typical of its era.

[Buzby58]

Thanks for all the suggestions - much appreciated.

As far as I can tell the hydraulics are functioning correctly - what sort of travel should the lever on the end of the slave cylinder have? It's moving an inch or so and I'm just wondering if that's enough.