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Bleedin bleedin clutch

Posted: Fri Apr 10, 2015 5:47 pm
by prothed
I'm just posting this because it's always entertaining to read of others misfortunes.

Before I took the popup off the road the hydraulic clutch had started dragging to the point where it wouldn't disengage at all and the lever was back to the bar with no pressure...

Put a new seal kit in the MC.
Slave cylinder and seal looked good, so cleaned and reassembled.
Everything back together.
DOT 4 fluid, bleed, bleed, bleed.

Nothing.
Exactly as before. It feels like the line is full of air - no pressure at the lever.
No fluid leaking anywhere.
Used a mityvac vacuum bleeding gadget.
Nothing.
Got a big syringe and reverse bled it from the slave cylinder.
Nothing.
Took off the clutch cover and the centre is moving, but only about a millimetre.

I hate this clutch and I especially hate whoever dreamt up brake fluid that spreads everywhere and strips paint.
Should have used DOT 5.

So I've just ordered a new seal for the slave cylinder. What else can it be???

Re: Bleedin bleedin clutch

Posted: Fri Apr 10, 2015 7:56 pm
by callyboy
Had the same problem with mine :( I have just replaced the slave cylinder seal last week on mine. Lost my clutch over winter. Johnr explained that they pick up loads of crap where they are and tear the seal :(

I seem to remember on mine when i rebuilt the bike that the problem was at the master cyclinder end. Bubble in the bend at the top ????pumped the bastard for ages and tied the lever back over night with a tie wrap. Hope that helps.

Pete

Re: Bleedin bleedin clutch

Posted: Mon Apr 13, 2015 3:09 pm
by Pedda
Try pressing the slave cyl back home as far as it goes. Then start bleeding. That way you avoid having too much air in the system from start.

Re: Bleedin bleedin clutch

Posted: Mon Apr 13, 2015 5:15 pm
by johnr
when the seals fail, they dont tend to leak, what happens it that they just pull in air on the backstroke, you pull the lever and it does little, but when you release it, it pulls in a bubble of air.

Re: Bleedin bleedin clutch

Posted: Mon Apr 13, 2015 7:22 pm
by prothed
Thanks chaps. New seal is in, but I won't have a chance to bleed it until tomorrow night. Hold your breath...

Re: Bleedin bleedin clutch

Posted: Mon Apr 13, 2015 8:30 pm
by fossie
When I bled the pop up project clutch, I held the slave piston in the housing with g clamp , as Pedda suggests, this way you only bleed the line when happy bolt cover back in place , but don't forget. Pushrod , Believe it or not people have.

Leaving it overnight with lever tied back usually bleeds it's self.

If you are using goodridge type hose it may well take forever to bleed ,the pressure from master cylinder isn't sufficient enough to move trapped air in such a tight space.

Re: Bleedin bleedin clutch SOLVED

Posted: Wed Apr 15, 2015 3:30 pm
by prothed
CLUTCH NOW WORKS

woo hoo

Reverse bled. Got out bubbles from MC end by pumping the lever forever. Left overnight with lever tied back.
(Not sure what tying back the lever does as it seals the system - but I'm not arguing).

How the hell they do this at the factory I don't know.

Just need to repaint the MC now. Bloody brake fluid.

Re: Bleedin bleedin clutch

Posted: Wed Apr 15, 2015 5:08 pm
by Pedda
Result!

Re: Bleedin bleedin clutch

Posted: Wed Apr 15, 2015 10:47 pm
by callyboy
Exactly what i done/said :)

Pete