32 replies to this topic

[se7enmvu]

I've just come indoors after giving up trying to bleed my clutch.
The mini is a standard 83 city and I'm using an easy bleed. When I connect to the tyre I get a jet of fluid squirting out of the top of the metal master cylinder can.
I'm guessing this is a pin hole due to corrosion and isn't a pressure relief?
It's difficult to see at the moment as the brake master cylinder reservoir is obscuring the view.

[nicklouse]

The cap has a hole in it for venting so any other hole is a failure.

[se7enmvu]

Thought as much. Guess it was just wishfull thinking.
Ordered a new one and not looking forward to fitting it.

[se7enmvu]

Well I fitted a new master cylinder today along with a new hose. I've bled it every which way but its not making any difference.
With the clutch pedal depressed I'm still getting gear grinding when trying to select.
The Haynes manual says the gap between the throwout stop should be 6.5mm. My gap is between 7-8mm. Is this the issue.  20210210_185928.jpg   33.85K   0 downloads

Also the throwout shaft freely rotates 1/4 of a turn back and forth. Is this normal?

[floormanager]

The bottom plunger does wobble around 1/4 of a turn.  Without the arm in, it will rotate completely.  Do the nuts touch the case?  You can wind them right out and see if that makes a difference to your clutch engagement.  They are there to stop you pushing the crankshaft too much should there be an issue.  They should just touch the case in use but to see if it helps your clutch you can back them off and see if you still get a crunch.

 

When did it start crunching, what happened which caused it to crunch (eg., fitted a new clutch etc)?

[Ethel]

The gap is without the pedal depressed? Bigger is fine as far as clutch operation goes. The purpose is to stop the clutch being pushed farther than is needed to release it because that puts unnecessary load on the crank bearing. If the gap closes completely, with pedal held down, your hydraulics are likely ok. 

 

You could increase the throw out gap even more and see if it helps. Test it by trying to rolling the car: ignition off, in 4th gear, clutch down.

 

The slave mounting bracket flexing can do enough to scupper Vertos, so look for that too. All the bolts tight?

 

Floor manager inspired edit: Must type faster!

 

Your diagram show that the arm 'n plunger is ball & socket joint - so the plunger should move equally in  every direction about the ball. I think a quarter sounds a little excessive, but it's a subjective judgement. You might get a better idea looking for play between the arm & plunger.

[se7enmvu]

The bottom plunger does wobble around 1/4 of a turn.  Without the arm in, it will rotate completely.  Do the nuts touch the case?  You can wind them right out and see if that makes a difference to your clutch engagement.  They are there to stop you pushing the crankshaft too much should there be an issue.  They should just touch the case in use but to see if it helps your clutch you can back them off and see if you still get a crunch.
 
When did it start crunching, what happened which caused it to crunch (eg., fitted a new clutch etc)?

The nuts appear to touch the case but I'm not sure they come to a stop against the case.

The engine was removed so I could spruce up the engine bay and repaint the subframe. Prior to the engine coming out the gears changed fine although it felt low on the pedal.

[se7enmvu]

The gap is without the pedal depressed? Bigger is fine as far as clutch operation goes. The purpose is to stop the clutch being pushed farther than is needed to release it because that puts unnecessary load on the crank bearing. If the gap closes completely, with pedal held down, your hydraulics are likely ok. 
 
You could increase the throw out gap even more and see if it helps. Test it by trying to rolling the car: ignition off, in 4th gear, clutch down.
 
The slave mounting bracket flexing can do enough to scupper Vertos, so look for that too. All the bolts tight?
 
Floor manager inspired edit: Must type faster!
 
Your diagram show that the arm 'n plunger is ball & socket joint - so the plunger should move equally in  every direction about the ball. I think a quarter sounds a little excessive, but it's a subjective judgement. You might get a better idea looking for play between the arm & plunger.

Yeah the gap is without the pedal depressed. The unit has only done 5k so I'm hoping wear isn't the issue.
I can't remember if I changed the slave when I recommissioned it in 2014 so it could be the original.
I never noticed any movement but it's something else I can check.

Thanks guys

[MiniMadRacer]

If you pump the pedal up and down three or four times and then hold it down does this make any difference?

[MiniMadRacer]

And check the slave cylinder for weepage, if the master cylinder "rusted" through its obviously very old, if the slave cylinder is as old, its likely to have some "seal" failure and a new master cylinder will put more pressure on a worn slave cylinder..

 

As a matter of course if I replace a master cylinder I replace the slave at the same time (and the hose as you have done) given the cost and the likelihood they are the same age

[se7enmvu]

Pumping the pedal doesn't make any difference.

So it's most likely a hydraulic problem and through elimination I guess the slave is the issue.

I fitted a new one to my mpi last summer so if all else fails I'll swap it for that tomorrow. Its booked in for an mot Friday morning.

[croc7]

A) Remove the return spring 1G5999 (#36)

B) Pull the top of the arm away from the engine until it stops

C) Loosen the locknut and unscrew the stop bolt (#39) until it contacts the arm, then screw it back to .015" clearance, still pulling the arm back

D) Tighten the jam nut on the stop bolt, replace the return spring, and you're done.

E) be sure the Stop nut #25 and not touching the cover (#17)

A) Remove the return spring 1G5999 (#36)

B) Pull the top of the arm away from the engine until it stops

C) Loosen the locknut and unscrew the stop bolt (#39) until it contacts the arm, then screw it back to .015" clearance, still pulling the arm back

D) Tighten the jam nut on the stop bolt, replace the return spring, and you're done.

E) be sure the Stop nut #25 and not touching the cover (#17)

 

Edit; Just realized the problem was with a Verto equipped car.  Doh!

Edited by croc7, 10 February 2021 - 09:54 PM.

[MiniMadRacer]

The above is for the pre verto setup, I think (might be wrong) the issue is with a verto clutch,, the short stuby arm as opposed to the long one

[se7enmvu]

Today I've fitted what I thought was a good slave cylinder.
Took the old one off and it was a bit damp behind the rubber cover.

Bled it with the easy bleed until it ran clear. Made no difference.

Removed the carpet and sound deadening thinking they are restricting pedal travel. Made no difference.

Manually bled it with an assistant. Surprisingly quite a bit of air came through the bleed tube but made no difference.

Watching my assistant press the pedal with the engine running and the throwout shift moves about quite abit. With the engine off it can rotate 1/6 of a turn.

When the pedal is pressed the throwout moves in approx 7.5mm.

I'm at a loss as to what's causing it now I'm tempted to remove the new slave that was fitted to the mpi last summer but I can't see it fixing it.

Before the engine came out there wasn't a problem.

[se7enmvu]

Well I've removed the new slave off my mpi and fitted it to the city. Bled it with the easy bleed and it's made no difference whatsoever.
So glad I decided to spend my evening working in sub zero temperatures.
I'm going to cancel the mot and put it away until summer.