Clutch Stuck - Disengaged.

[Little Pink Steve]

Hi guys,

Just changed all the fluids on my new FJ.  I found the clutch a right pain to bleed, but got there in the end. I unbolted the slave and used a vacuum to draw the fluid through. But since refitting the slave the clutch is now permanently disengaged, no drive at the wheel.  When trying to bleed it conventionally, pumping the lever, I need not notice any fluid returning to the reservoir.

Is the return port blocked and if so what is the easiest way to clean it?

Cheers.

[PaulG]

I'm guessing the slave might be seized?  Or if it's just a plugged return, regardless about the only thing you can do is rebuild it (with an OEM kit), or (from what everyone says) replace it with a replacement slave from RPM.


http://rpmracingca.com/products.asp?cat=39&filter=Slave

[Pat Conlon]

Remove the slave, open the bleed port, press in the slave piston (fluid will squirt out the bleeder) holding the piston in, close the bleed port, reinstall the slave.

You pumped the clutch lever with the slave removed and extended the piston.
See post #3: http://www.fjowners.com/index.php?topic=1808.0
There is no need to remove the slave for bleeding.

Take the time now to clean out the reservoir. Take out the splash plate on the bottom and clean out all the gunk accumulated under the splash plate. That stuff can, and will, clog your relief port.

Cheers

[Little Pink Steve]

I had vacuum bled it with the slave unhooked and piston clamped back.

I have since cracked open the nipple and now the clutch is engaged........now it won't  disengage. I've not seen any fluid returning to the res........wonder if the return port is blocked.

[Pat Conlon]

Very possible

[movenon]

Think Pat is on the right track.  "Take the time now to clean out the reservoir. Take out the splash plate on the bottom and clean out all the gunk accumulated under the splash plate. That stuff can, and will, clog your relief port."    Had the same problem a few years ago.  The port is real small. 

George

[aviationfred]

My advise would be..... Clean the reservoir as mentioned earlier.....after cleaning the clutch reservoir, with the slave cylinder removed, push the piston in by hand until it bottoms out. bolt it back on. Fill the reservoir with fluid and vacuum bleed the cylinder. Actuate the clutch lever, There may not be much pressure at first as the slave cylinder piston is being pushed out and there is no resistance before it contacts the clutch push rod. Make sure the reservoir does not go dry as the fluid is filling up the slave cylinder.


Fred

[Earl Svorks]

  Steve,
a master cylinder that has not been apart in half of forever, can build up a lot of crud under the boot on the
outside end of the plunger. That crud can build up between the plunger shoulder and the snap ring in the bore. It can prevent the plunger from returning all the way back. It only takes a very small loss of travel to prevent the plunger from coming back far enough to open the compensating port. An ill fitting lever can produce the same result if it does not provide a bit of clearance between it and the piston in the MC. It's very difficult to get the boot off without tearing it up, if you are going to take the snap ring out to service the MC. You'd do well to get a cylinder kit in advance.
     Cheers
Simon

[ribbert]

[quote authour

.......my advise would be..... with the slave cylinder removed, push the piston in by hand until it bottoms out.

[/quote]

As Simon mentioned about crud building up between the outer boot and the piston, so does it build up on the other side, where the fluid (and moisture) sits behind the piston.

Pushing the piston all the way back, beyond its normal travel, forces the seal over the rough, corroded, flaky, crud lined surface it doesn't normal travel over, this seriously chews up the seal lip.

As for the master cylinder, if you are going to remove the piston, do not refit the old cups.

There's an endemic attitude here on the forum that treats hydraulics with the casualness of re sealing a garden hose. There are long standing rules that were set for good reason and have stood the test of time and experience.

If removing a hydraulic seal/cup from its bore, there is only one rule about replacing it, don't! Bin it. Simon alluded to this and I'm saying just do it. I know we're talking about clutch's here but no one seems to differentiate between this and brakes. What worries me most is people "servicing" the hydraulics on their brakes. Pull it all apart, re finish (scratch the shit out of) the cylinder by methods that astound me (no one owns a hone) and re assemble with old cups, now rotated into a different position.

Yeah, you'll probably get away with it, after all average mileages are pretty low, but you wouldn't catch me riding a bike that had just had such a brake "service", and I know just what you can get away with.

Come on guys, get with the program, if your hydraulics are stuffed (bleeding issues aside) replace them, they're relatively cheap. Also keep in mind, if done right, you should never have to do this more than once in the life of the bike.

IMO

Noel

[Pat Conlon]

Yep, kinda like replacing those 30 year old oem rubber hydraulic hoses huh?
....after all, they look fine on the outside...

http://xjbikes.com/forums/threads/why-you-need-to-replace-original-brake-lines-w-pics.41400/

[ribbert]

Yep, kinda like replacing those 30 year old oem rubber hydraulic hoses huh?
....after all, they look fine on the outside...

I agree Pat. I can't see the connection but as forum elders we have a responsibility to raise safety related issues whenever the opportunity presents itself.

I endorse Pat's recommendation in getting the rid of the old rubber hoses.

Noel

[Mike Ramos]

Holy Toledo!

Hell hath frozen over...!

[ribbert]

Holy Toledo!

Hell hath frozen over...!

Good onya Mike, glad I made somebody's day.

Noel

[Little Pink Steve]

Just rebuilt to slave with new seals and all is now good.