Hydraulic clutch woes

[ronski]

Was driving along and suddenly my clutch decides not to disengage any more. Whatever you wanna say about clutchless upshifting and if its any good or not, it definitely gave me the practice I needed to be able to drive the fucker home.

So I bled the system and rebled it, still no good. Replaced the master cylinder pistons and seals, and also the slave cylinder seal. Bled the system again. Rebled it. Still no good. With the back wheel in the air, in first gear, clutch in, trying to spin the back wheel feels exactly like the clutch is out (ie it wont fuckin spin)

I even tried adding length to the clutch pushrod with a few shims but still no good.

Any idea what I should try next? Was gonna try replacing the slave cylinder piston, but I dont see what this would do. Yes its a little corroded looking, but only on the part outside the seal, ie outside the hydraulic system. So I dont know if it would make any difference to replace it.

I guess Ill have to drain the oil and take the clutch cover off, but wont really know what Im looking at. Anyone got any advice/tips? Cheers.

By the way, I recently fitted a braided steel hose. It worked fine, until it suddenly didnt. Air in the system somehow? Ive really bled the fuck out of it....

[vitamine27]

you're missing one small piece of info, the lever goes dead? if so, then it's just the copper rings aren't doing the biz, and it sucks a bit of air occasionally,

bleed it from the top next time,
once the line is full, let it stand, then the air will be at the top, so bleed out top banjo bolt

[ronski]

Nah man, lever doesnt go dead, it still has pressure, and when the bike is at a standstill i can hear something happening down at the clutch, just seems that its not disengaging fully. Does this make sense?? Thanks for the input anyway, at least im eliminating all the things it could be!

[vitamine27]

next poss cause, clutch started slipping, built up heat, warped plates, and now will no longer relax pressure enuf to disengage,

could pop clutch cover off and see if clutch center is being pushed the 4 or 5 odd mm that should disengage it, sometimes I've been able to see or tweak the plates thru the oil filler cap to see if they were in released state

[ronski]

Cheers Ill have a look, never thought of just looking through the oil filler. That might save me a lot of work. Thanks!

[ronski]

Took oil filler cap off and i can see the plates moving when i pull the clutch, like you say bout 5mm. So why wont it disengage? Release bearing? Help

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Got this little troubleshooting guide off a car website. Nothing makes sense to me apart from the fluid too high bit (it isnt). Can anyone shed any light on what the other stuff means? Ive never worked on a clutch before so its all a bit arcane to me

Clutch fails to disengage (unable to select gears)
- Hydraulic fluid level too high
- Clutch disc sticking on gearbox input shaft splines
- Clutch disc sticking to flywheel or pressure plate
- Faulty pressure plate assembly
- Clutch release mechanism worn or incorrectly assembled

Edit: I realise that most cars only have one friction plate and a bike has multiple, maybe none of this applies to a bike??

[ronski]

Anyone know about clutches????