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No clutch suddenly

Posted: 12 Jul 2018, 18:29
by CovKid
Started this in chat, but clearly needs to be in mechanical now. Not encountered this one, and replaced lots of clutches.

Short story, clutch was working fine, then after a drive and starting up, I struggled to engage reverse, or in fact any gear with engine running. Fine with engine off. No clutch as such. Pedal seems to come to a rock hard stop about halfway through travel. No leaks at master or slave.

With a helper, any input via pedal makes no effect at gearbox end as slave appears fully extended and release arm horizontal.

My first thought is release bearing or release fork. I guess I'll have to pull gearbox, but any other ideas?

Re: No clutch suddenly

Posted: 12 Jul 2018, 19:05
by Cecil
Is it the slave cylinder bracket fractured, so whole cylinder moving up when pressure applied? -Wishful thinking!
E D I T. Not sure that would result in solid pedal . Slave at end of its travel might ?

Re: No clutch suddenly

Posted: 12 Jul 2018, 19:07
by Smcknighty
Pull the slave first - maybe it’s over extended or stuck somehow?? If you put it in gear and turn the starter does it try to move? E.g is clutch actually disengaged or engaged?


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Re: No clutch suddenly

Posted: 12 Jul 2018, 19:25
by CovKid
If put in gear, vehicle will lurch forward if you try starter.

Re: No clutch suddenly

Posted: 12 Jul 2018, 19:33
by itchyfeet
Can't add much except I have fitted gearbox and got bearing clips wrong side of arm and clutch is dead so it does not take much wrong with bearing to kill clutch.

Re: No clutch suddenly

Posted: 12 Jul 2018, 19:48
by CovKid
Will just crawl underneath and see if slave pushrod can be pushed back. 5 mins.....

Re: No clutch suddenly

Posted: 12 Jul 2018, 19:54
by Smcknighty
If the thing looks to be stuck fully extended and yet the clutch is engaged still presumably something broke inside the bell housing.


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Re: No clutch suddenly

Posted: 12 Jul 2018, 19:55
by CovKid
Right. Slave pushrod can be pushed back with some grips and returns so theres pressure in the line. That would seem to rule out hydraulics I guess. Feels normal anyway. Not a leak anywhere. The operating arm doesn't budge though. Stuck as a stuck thing. Box has to come out then.

Won't know until it comes out but does sound like fork or release bearing. Unlikely to be clutch as that was working fine. Machine7 is very close to me (streets away) and thankfully they stock the fork, so if its that I can get one. GSF carry the bearing and thats not too far away either. Can't think of anything else that would cause this.

Re: No clutch suddenly

Posted: 12 Jul 2018, 20:09
by multisi
Maybe one of the arms has broken on the operating shaft, happened to my air cooled shortly after I got it many years ago. Its a good idea to fully weld them on to prevent it happening.

Re: No clutch suddenly

Posted: 12 Jul 2018, 20:15
by CovKid
Does sound like it doesn't it. :D Anyone want to take a non-monetary bet on what I'll find in there ?

In the meantime I've dug the puller out. Suspect operating arm will need to come off. My money is on the fork. I did try and move arm a few years back but didn't have a puller then. They don't yeild to a cold chisel I know that much. :D Thanks guys - getting nearer to the cause.

Re: No clutch suddenly

Posted: 13 Jul 2018, 07:48
by CovKid
Ah, further joy. Got up this morning and just before I jumped into car to go to work, spotted a nice puddle of brake fluid under camper rear wheel. I'm loving this :evil:

Re: No clutch suddenly

Posted: 13 Jul 2018, 08:01
by Cecil
Shortage of fluid - could that be the only issue you have with the clutch?
Maybe the fluid level warning light is inoperative.

Re: No clutch suddenly

Posted: 13 Jul 2018, 08:44
by CovKid
Well, for sure I'll be looking at that circuit before tackling anything else :D

Re: No clutch suddenly

Posted: 13 Jul 2018, 09:40
by Cecil
QUOTE With a helper, any input via pedal makes no effect at gearbox end as slave appears fully extended and release arm horizontal
-
My release arm looks approximately horizontal ,clutch at rest(pedal up).so I think that’s where it’s meant to be!
I guess it is tricky gauging The correct amount of force to put on the release arm to move it ,without doing damage.
Could air in the system have caused the clutch master cylinder piston to stick in a normally unused part of the bore?

Re: No clutch suddenly

Posted: 13 Jul 2018, 10:13
by Smcknighty
Would do no harm to swap the slave first I guess. Might be jumping to conclusions too quickly


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