40 replies to this topic

[The Matt]

OK, well I've got a problem with clutch disengagement on the mini.

I had an A series engine in there, that worked fine so I am sure the master cylinder is working OK.

It's an A+ fitted with a diaphragm clutch set up. It's also fitted with.......

Ultralight flywheel (including spacers),
Ultralight pressure plate,
Orange diaphragm,
New clutch plate,
New plunger,
New hydraulic hose,
New slave cylinder and return spring.

So, the problem I had was that I couldn't seem to get it to adjust up enough to disengage.

I've removed the return spring, pushed the clutch arm to take out all of the play, then adjusted the return stop so that it is 0.5mm away from the arm and locked it in place. I've also tried adjusting the throw-out stop by getting my GF to sit in the car, pump the pedal a few times then hold it down, then I've wound the flanged nut up to the casing, got her to take her foot off the pedal, then I've tightened the flanged nut a further flat (60 degrees) and wound the locknut up to it. After I'd done this, I had a pedal that felt OK, but I couldn't quite disengage the clutch to put the car into 1st gear easily, though I could start the car in gear and lift off the clutch and drive (all of 30cm of driving). I also noticed that the revs dropped quite a bit as I tried to disengage the clutch. I am fairly sure that I have bled the system properly too.

Oh, I also noticed that the clutch arm off the old A series 1330 that I took out of the car had a crank in it (see top arm in pic below) and that the one I was trying to set up appeared to be straighter, so I tried swapping those.


Check me crank out. The problem is that I don't know which one is right, if it's supposed to have a crank in it, I could fit that one, but the ball end is worn, so that may create further problems :S

Now then, I was talking to a very knowledgable mini type person on MSN and they suggested checking that the diaphragm spring was flat (as in parallel to the flywheel). They also asked if I'd set the drive straps flat and I couldn't remember, so I thought it best to check those two points.

Tonight, I have just whipped off the clutch cover and inspected both the drive strap alignment and the diaphragm spring alignment. Both of those issues appear OK. So I am more than a little confused.

So, to summarise all of the above, I have a clutch system that seems to have no wear anywhere, yet it doesn't seem to want to disengage. I've tried bleeding the thing with the pushrod disconnected from the clutch arm and the cylinder forced back in as far as it will go (to make sure there is no air in the actual cylinder anywhere).

Somebody please help me as I'm gonna cry!!!!

PS: Sorry for the reaaaaalllly lengthy post! I'm trying to make sure I haven't missed any details!


EDIT: Search keywords:

Clutch lever clevis pin disengage crunching gears crunch <--------might help for future searches???

Edited by The Matt, 10 February 2008 - 11:34 AM.
search words added

[The Matt]

Actually, the more I think about it, the more I am certain that it's a hydraulic issue. One thing I could do with knowing is how much 'throw' the slave cylinder should have, it's as though it doesn't come out far enough to even meet the pushrod when the return stop is adjusted up to it, even after some pedal pumping. I've checked everything about the system apart from giving it another good bleeding. The problem I have is persuading the GF to sit in a car that she hates out in the cold garage.

Might put a post in the wanted section for a lady that likes to help on minis!

[minimender]

Check that the clutch plate slides freely along the crank before you fit it all together. Put a little copperslip on the splines and work it back and to then wipe the excess off.
If it dosn't slide freely then the clutch will drag and not dissengage propperly.

Course it might be something else entirely, but do it anyway.

[minimender]

Try cutting a peice of tube and sliding it over the rod that goes into the slave cylinder to lengthen it. If this works then you know that the rod is too short or you have the wrong arm on

[The Matt]

Thanks for the reply, I've checked that earlier, I unbolted the diaphragm/pressure plate and checked that the clutch plate wasn't binding on the primary gear, it seems OK to me

Man, I dunno, I dunno what the hell's wrong!

It does seem like it's just not got enough 'throw' in the system somewhere. It must be bleeding, it's gotta be

[The Matt]

Try cutting a peice of tube and sliding it over the rod that goes into the slave cylinder to lengthen it. If this works then you know that the rod is too short or you have the wrong arm on

Oooh, there's a good idea actually, cheers for that. It does seem like the problem may be either with the pushrod or the arm. I'll have a play with that tomorrow night. Might even get a threaded pushrod made up at work tomorrow

[minimender]

Could be just a missmatch of parts, I've had it loads of times.
All rods and arms are not the same , they kept changing them over the early years, especially when BL took over.
Just lengthen the pushrod

[The Matt]

Thanks for the help minimender. It probably doesn't help that I've swapped just about everything on the car!

Will post tomorrow with how it goes. Cheers

[Big_Adam]

I had to lengthen my push rod recently.

I got a 10mm tube from B&Q, drilled it close to pushrod size, heat, force,

The remount.

Did about an inch extra. OR! Push the clutch down with the boot off the slave cylinder. See where the piston is.

[Sprocket]

http://www.mancheste...p...nfo&sosid=9

If there is a crank in the arm, its been bent at some point as wear has built up in the mechanism.

Bending the arm, lengthening the rod is a bodge. The parts new are not that expensive. Bodging reduces the lever action. The other thing to consider is the later clutch master cylinders had a smaller bore, therefore, you get less movement at the slave. Some clutch pedals are also different with a little more travel. Add all these little things together with a little bit of wear on the mechanism and you can experience problems very quickly.

If you are not using a new plunger and arm, i would start there, I would also make sure there is deffo no air in the system, blead it, and blead it again.

Make sure the primary gear clearance is set correctly and not pinching up.

[JetBLICK]

IMO, i've seen a fair few examples of people who've had to bend the arm or lengthen the rod so that they can work the clutch properly with an ultralight flywheel, so i wouldn't myself consider that a bodge. My clutch straps where set dead level on mine (steel ultralight, lightend backplate, AP 'rally' plate, grey diaphragm and a heavy duty release bearing), even tho dead level i still needed a longer rod, so a mate welded a bit on the end to lengthen it... hardley a bodge if it permanently cures the problem

Matt, just space it out with nuts (of the nuts and bolt kind ) till you get an idea for how much longer it needs to be then get a bit welded on it, i wouldn't trust something like a spacer that could easily fall out as a permanent fix

[Jammy]

I had the same problem with my setup Matt. I'll try and find the topic. At the end of the day I bit the bullet and took the whole assembley out of the car, added another 0.5-1mm of spacers on the drive straps and that cured the problem. It was really difficult to work out, because from eye it looked like the drive straps were perfectly level the first time!

Firstly though, I think someone in the past has bent that arm. Its definitely meant to have a crank in it. I'd say its been done deliberately too, as I would have though something else would break before a foot on the clutch pedal would bend that piece of metal!

If I was you, I'd get a brand new clutch arm, fit that, and if that doesn't cure the problem, look at spacing the drivestraps a touch more.

EDIT: My topic, I got some really good advice.

[The Matt]

I'm still haveing problems with this!!!!

I just don't get it.

When I get moving, the clutch disengages, the car doesn't stall if I come to a halt in gear with my foot on the clutch, I can drive it OK. When in neutral I depress the clutch and it doesn't make the engine stall.....

Without the starter fitted, I can get the GF to press the clutch pedal, then spin the clutch with my finger (just) so it's definitely disengaging. It just doesn't like to go into gear to easily.

Is there anyone out there that could tell me how much movement I should have at the slave cylinder/pushrod? I have been looking at the clutch pedal tonight and it sits lower than the brake pedal by 1/2" - 3/4" and there is a little bit of play in there. Is this my problem? Too much play in the deal resulting in not enough master cylinder movement, therefore my slave isn't moving far enough???

[Sprocket]

Check your primary gear clearancies, infact, check the primary gear bushes, try a different primary gear.

[The Matt]

I know that the clearances were OK when I built it, I bought a new thrust spacer doofah for it and everything. Plus, it's an SC primary gear, so it's not like I can just swap it out for another one without buying new.

I really am pretty sure it's a hydraulic/pedal issue now though, the clutch works, it's just not working quite enough. Surely if the primary gear was pinching up it wouldn't let me coast to a halt in gear with my foot on the clutch? Surely that'd make it stall wouldn't it?