Clutch back in, and not working- Any bright ideas?
Discussion
Clutch, slave and everything came out the other week after the slave seal finally gave up the ghost. Since mine is an early cerb with a late model engine in, I thought I would try to avoid the hassle of working out what fly-wheels etc came from what, and just recondition the existing stuff. The slave cylinder that came out actually looked fine, but I wasn't happy with the obvious machine grooves that were left on the slave since its manufacture, so I honed all important surfaces, and put it back together with a new release bearing and new seals. The clutch itself was actually fine, but all the same it got sent off for re-manufcture. It came back all shiny, with new friction plates and with reground intermediate plate. My only outset concern was that the company that did the clutch work, having completed the job, told me that i should have sent them the fly-wheel too so that the thing could be set up (?). I was a bit peeved, as they never mentioned that beforehand, and I would have been happy to have done so if I thought I needed to. Anyway, they said it would probably be fine, so I bolted the clutch on, and since connected everything up together. Having bled the clutch, it feels just like before, and I definetely aligned the slave correctly, so I'm confident that its been bled properly.
Just one problem. I cant select a gear when the engine is running. I've done the whole job obn my gravel driveway, so I'm really dreading having to take it all to bits again. So, anyone out there with any bright ideas for what might be up? Anyone also know what the clutch people (who re closed till Tuesday) might have meant by adjusting the clutch?
Your thanks in advance, Rob.
Just one problem. I cant select a gear when the engine is running. I've done the whole job obn my gravel driveway, so I'm really dreading having to take it all to bits again. So, anyone out there with any bright ideas for what might be up? Anyone also know what the clutch people (who re closed till Tuesday) might have meant by adjusting the clutch?
Your thanks in advance, Rob.
I had a similar problem when i did mine,i had difficulty engaging the gears,can you get it in gear without the engine running,with the clutch pedal pushed down,start the car & move off?It could just be you need to adjust the clutch pedal travel,there is adjustment on the threaded rod behind the pedal.I did this on mine & it was fine.
If you 'honed' the slave cylinder to get rid of score marks, you may well have honed it too much and the seals arent working. I had a problem with a CT Slave Cylinder that was traced to a faulty batch of seals - 0.05mm out of tolerance! (CT to there credit drove straight down from Shffield with a brand new one immediately)
Hate to say it but when your fitting a new clutch you really should fit a brand new Slave Cylinder.
Sorry, bet that makes you feel so much better
Hate to say it but when your fitting a new clutch you really should fit a brand new Slave Cylinder.
Sorry, bet that makes you feel so much better
The honing literally takes off microns, and it wasn't done because the surfaces were scored through use, it was just to smooth out the machining grooves. Anyway, its not loosing any fluid, so the seals are definitely working, and I cant imagine the difference in cylinder displacement is anything like enough to cause the travel to be reduced by any appreciable margin.
Just tried adjusting the pedal out for maximum travel, but alas she still won't change gear whilst running. Indeed, it when I try to start the car in gear with the clutch fully in, there's still enough grip in it to pull the car forwards on the starter.
Just tried adjusting the pedal out for maximum travel, but alas she still won't change gear whilst running. Indeed, it when I try to start the car in gear with the clutch fully in, there's still enough grip in it to pull the car forwards on the starter.
Edited by brogenville on Friday 21st March 17:44
Who relined your plates for you? are they aware that AP clutches use a peculiar thickness of friction material slightly thinner than almost everyone else uses?
The early clutches can cause problems because the 6 individual pedestals are shimmed in three pairs against the flywheel (you did remember to put the shims back in didn't you?) and mixing them around can sometimes give uneven clearing on the friction plates.
The other thing about the early clutches is that instead of having star washers to limit the movement of the central iron ring they have 3 pairs of circlips which are easy to damage if you don't get them all lined up perfectly before fiting and that can cause drag on one of the friction plates.
It is posible to recondition the clutches and have a faultless refit if you're aware of all the permutations of AP clutches through the years and you're anal about what you do at every step, but if youre not au fait with the ins and outs of early cerbera clutches you're often much much much better of payng someone who is. Anyway, upshot is it's coming apart again isn't it?
The early clutches can cause problems because the 6 individual pedestals are shimmed in three pairs against the flywheel (you did remember to put the shims back in didn't you?) and mixing them around can sometimes give uneven clearing on the friction plates.
The other thing about the early clutches is that instead of having star washers to limit the movement of the central iron ring they have 3 pairs of circlips which are easy to damage if you don't get them all lined up perfectly before fiting and that can cause drag on one of the friction plates.
It is posible to recondition the clutches and have a faultless refit if you're aware of all the permutations of AP clutches through the years and you're anal about what you do at every step, but if youre not au fait with the ins and outs of early cerbera clutches you're often much much much better of payng someone who is. Anyway, upshot is it's coming apart again isn't it?
trackcar said:
The other thing about the early clutches is that instead of having star washers to limit the movement of the central iron ring they have 3 pairs of circlips which are easy to damage if you don't get them all lined up perfectly before fiting and that can cause drag on one of the friction plates.
Anyway, upshot is it's coming apart again isn't it?
The clutch recon was done by auto and industrial, who I've been told do good work, and indeed do race applications too. The guy there did seem happy about getting all of the clutch specs, and indeed before I sent it off, it looked as if there was about a ball-hair of friction material left above the rivets, and when they came back I was worried as they barley looked any thicker than before. Anyway, upshot is it's coming apart again isn't it?
I've not seen any of these star washers, but I'm happy that thats just because its an early car. I do know what you mean about the pedestsal shims though, and I checked that they were in place before I fitted the clutch. I'm not entirely sure what you mean about circlips though? When I got the clutch back, the central iron plate was free to lift out- is this bad?
Are you happy that the clutch has been bled ok?When i bled mine the first time the clutch fluid was dissapearing rapidly,upshot of that was the master cylinder seals were f****d,replaced the master cylinder & all was ok........by the way i know its not very helpful but i agree with Jensena,should have fitted a new slave cylinder,but be aware there are 3 different types!!!If its any consolation i got the wrong one,fitted it,had a problem with the clutch slipping & had to take it all to bits again!If you get a new one.check the piston length is the same as your original,mine was 5m/m longer.
Edited by esso on Friday 21st March 18:54
Edited by esso on Friday 21st March 18:55
In truth, I though it was bled at first, but latterly, and using an aggressive bleeding technique, I did manage to get more air out of the system. The point is, the pedal does feel plenty firm, and having put over a liter of clutch fluid now, I'm convinced that it must be bled.
Cheers though.
Cheers though.
Can I ask, if a slave cylinder comes out, and isn't scratched or scored internally in any way, why would it need replacing? Surley its just a solid lump of metal, and as such with a new set of seals will be good as new?
The only reason I smoothed the inside of my slave was that I felt that the machining groves left from when it was turned on a lathe could be abrasive to the seals.
The only reason I smoothed the inside of my slave was that I felt that the machining groves left from when it was turned on a lathe could be abrasive to the seals.
dProviding one of the holes was at the top it should have bled fine.
If it feels similar to how it did before then it would suggest it's clear of air and moving.
When you bolted the clutch back to the flywheel how tight were the bolts? If you had a good few turns on each and they were stiff before they tightened up, then it would suggest to me you have too much friction material there. Even when you are releasing some of the spring pressure you’re not releasing it all.
One other thing I have heard before is of one of the friction disks sticking to a pressure plate.
I take it you've had a good few tries at getting it to disengage?
If it feels similar to how it did before then it would suggest it's clear of air and moving.
When you bolted the clutch back to the flywheel how tight were the bolts? If you had a good few turns on each and they were stiff before they tightened up, then it would suggest to me you have too much friction material there. Even when you are releasing some of the spring pressure you’re not releasing it all.
One other thing I have heard before is of one of the friction disks sticking to a pressure plate.
I take it you've had a good few tries at getting it to disengage?
I'd still bet on it not being bled properly.
I had exactly this with my new clutch and slave recently; Even a tiny bubble in there can prevent enough clutch movement. The clutch only moves about 6mm anyway, so any less - especially when friction plates are new - can prevent disengagement.
With mine, the mechanic swore it was bled. But it didn't work. Eventually he got some form of vacuum gadget to bleed it (since its pretty difficult to do manually, a couple of pushes on the pedal and the reservoir's empty) and hey Presto! it started working.
(Capital P on Presto as it is someone's name!)
Anyway - you get my drift!
A.
I had exactly this with my new clutch and slave recently; Even a tiny bubble in there can prevent enough clutch movement. The clutch only moves about 6mm anyway, so any less - especially when friction plates are new - can prevent disengagement.
With mine, the mechanic swore it was bled. But it didn't work. Eventually he got some form of vacuum gadget to bleed it (since its pretty difficult to do manually, a couple of pushes on the pedal and the reservoir's empty) and hey Presto! it started working.
(Capital P on Presto as it is someone's name!)
Anyway - you get my drift!
A.
brogenville said:
When I got the clutch back, the central iron plate was free to lift out- is this bad?
Yes that is bad. The circlips and star washers depending what you have fitted are there to limit th release of the iron ring back from the first friction plate so that it guarantees the release of teh second friction plate. Either the circlips have been removed for some reson (they canot fall out naturally, though the star washer type can) or you have the plate in upside down so the circlips don't actually reach the locating pins they press over. Either way, the release of the second plate may be compromised.As has been said above though, even though you have got the slave in teh corect orientation, make sure you have it bled properly .. a vacuum bleeder is by far the best way (then a pressure bleeder second best).
Thanks for the replies guys. I think I will have another go at bleeding it (mainly because it doesnt involve taking it all to bits again!) and I'll see if I can get hold of a vacuum bleed kit. I say it feels like it did before, but who knows, I could be wrong. As far as too much friction material goes... the bolts holding the clutch to the flywheel were obviously reasonably tight going on, but they didn't feel as if they wanted to stop moving before the clutch case touched the flywheel surface.
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