7 replies to this topic

[colinu]

OK, spent the past 4 years rebuilding/restoring my Mini and took it for its first real run today... 7 miles to our equivalent of the DLVA to get registered. Got there OK, but on the way back the clutch started playing up to the point where I couldn't select any gears. Here's the details...

 

Going there the clutch pedal was 'accceptable' - pedal was maybe a little soft at the top but the clutch bit firmly approx half way through the pedal's travel.

On the way back after maybe mile (mixed traffic) the bite started to go further down towards the floor. Over the next mile or two (maybe 10 mins in mixed traffic) the clutch gradually got worse until I could no longer get into any gear... had to abandon the Mini

 

Pre-verto clutch.

Slave cylinder, braided hose to it, clutch arm/bearing/etc are all new.

Master cylinder is the original 'bean can' that came with it.

I can't see any hydraulic leaks.

I can see the clutch arm start to move when the pedal is 1/2 way through its travel. The arm moved through 0.55" when I set the clutch up during the rebuild but I can't be 100% sure if that's still the case (was dark and I didn't have a ruler when I broke down).

Clutch return and throw-out were all adjusted/gapped correctly before I set off and didn't seem to have changed.

I reused the old clutch plate and orange diaphragm (which at the time I believed to be OK... but maybe not?), but fitted new lighten backplate, tabs, and lightened flywheel.

 

So before I go to the trouble of tearing the clutch plate etc out, what should I be looking for, and more importantly how to troubleshoot it? My thoughts are currently lying with either a worn master cylinder, or worn clutch plate. 

 

   Cheers,

   Colin.

 

P.S.

I managed to nurse the Mini home tonight but had to adjust the return and throw-out stops WAY more than is recommended (just enough to get a little play back in the pedal and limp home in 3rd gear). I don't want to 'over adjust' them further as I don't want to run the risk of worn/spun thrust bearing... which was the initial cause of my engine seizing 4 years ago.

[bpirie1000]

I trust the clutch was torqued up to correct specs?

[Ethel]

I'd start by investigating the hydraulics, partilularly the slave, they can suffer from inactivity. Though the lack of "push" ought to be visible at the throwout stop when the pedal's on the floor.

[KernowCooper]

+1 with Ethel get someone to push the clutch down and see if the overthrow nuts are making contact, paying attention to where the clutch starts to lift in relation to pedal travel, then look at the hydraulics to identify where the loss of travel is.

Edited by KernowCooper, 11 February 2014 - 02:31 PM.

[colinu]

I just reset the return gap to 20thou, then wound the throw-out nut away from the wok. Measured the movement at the top of the arm, and instead of the 0.55" I expected I'm only seeing 0.375" (which results in a measly 1/16" movement at the throw out). So looks like hydraulics are the culprit. Going to bleed the clutch first before starting to look at the slave or mater cylinders.

 

One thing that did cross my mind is this... are there different bore sizes of clutch master cylinder (i.e. does it need to be matched/correct for the slave I am using)?

 

   Cheers,

   Colin.

 

 

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[colinu]

Bleeding the clutch has got me back to a firm pedal and good clutch operation. My only worry/paranoia is will it stay like that or will it go bad again (e.g. Do I have a master cylinder that is slowly sucking in air?). Only time will tell!

[mk1leg]

Check all unions are tight as air can seep in but fluid does not escape......

[colinu]

Will do :)