dprantl

The slave cylinder rod for a single-disc clutch is a different length than one for a dual-disc clutch.

Dan
'91 928GT S/C 475hp/460lb.ft

mark kibort

thats why the supplier said that it was 83 to 86. so, we got the right length rod, but the orientation is not the same. since my orientation of the hard line to the master is not in a stock location, i have some flexibilty on the orientation of the slave. its all bolted up now. certainly a huge differerence in the spring feel , and had to compress the rod into the slave body to get the bolts to thread. so, that looks good....................But, i dont remember having this much issue with the bleeding of the clutch. i either have to do the two man technique, or find some long tubing to do the brake reverse bleed technique.

the flyin' scotsman

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mark kibort

ill try it! forgot about this quick fix. thought i would need more fluid in the slave to do it. (like a tune up bleed normally when everything has been working fine).

Illl see if that works. no third hand today! so im on my own.


even thinking of rigging up a power bleeder to have a cup of fluid in it, with a tube out the main exit to push fluid into the slave .

mark kibort

HELP!!!!

Ok guys, i did almost every trick you guys told me to do.

1. got my pressure bleeder rigged up to put fluid in it, and attach it to the nipple of the slave. reverse flow the fulid to the reservior. made it over flow and caught the extra in a bunch of rags until the bleeder was out of fluid. didnt attache it until it was bubble free and then attached it, opened the valve and the fluid went up the system to the reservior. that did a little got 1" of pedal now.
2 . took off the slave and pushed the push rod in and out for 2 times as suggested. that got me another 1"
3. got the presssure bleeder rigged to do the traditional way of pressurising the reservior and pushed fluid out the bleeder valve . closed it after the reserviior was down to half full.. no air it seems.
pedal didnt change a bit.

4. took the slave off again and pushed the rod in 20 more times. it feels like it is moving fluid, but the pedal is still way down

i have about 1-2" of pedal feel, where something is moving, but its way down at the bottom of the travel of the pedal!!

I give up!!! what the heck. how can this be so hard??? what am i missing. ive gone through a half of a large bottle of superblue and im not getting anywhere.

any help would be GREATLY appreciated!!

mk

UncleMaz

Try the Jay Kempf/Wally P bleeding burp master method (Karl Ruiter passed on to me/still haven't tried). I am told it takes 10 minutes and is undefeated:
Jeff,

Not sure why you didn’t call back, but in case your system is still not bled, here is the method. It takes 10 minutes.

Per Jay Kempf:
Take the push rod off of the pedal.
Remove the snap ring from the master cylinder bore.
Slowly and carefully pull the guts of the cylinder out until you can just barely tilt the piston seal back at the top enough to let the air bubble out, then carefully reinsert the seal and put everything back together.

mark kibort

com'on!! really?????? it shouldnt be this hard. stuff was working before , now i got 1" of pedal and have gone though a quart of superblue already!

the only thing i havent done yet is the two man method........ pop is coming over to do that , but i dont think that way works, personaly! heck , how many of these things have i put together. none of them were this bad!!! i cant really say its the master, becuase it was working before. but you never know.

mk

Dutch 928 fan

Did you push the rod into the slave fully when you installed it? I found that if I did not do that, that it was hard to get it on the threads to bolt on and that the clutch did not release when the pedal was depressed.

Anyway, there's one other thing you have not tried and that's the hose from brake to slave method. Advantage is that you can do it by yourself and you don't waste more brake fluid as you just pump it round and round.

Honestly, this was the only method that cleared my lines of any trapped air. The old fashioned way with a helper at the pedal and me at the slave opening and closing just did not do it as you have to push the bubbles down.

I hope you solve it soon. Hang in there. It is just always a bit more complicated than on those classic car tv shows where they fix up a car isn't it? They never seem to drop bolts or nuts into the abyss either...
Leo

the flyin' scotsman

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mark kibort

hey thanks leo. you can see how when pressure bleeding or forcing fluid using the pressure bleeder, that i there is an air pocket, fliud runs around it, and no air enters the system, but fluid still moves. the air pocket doesnt even budge. i imagine that this might be happening in the master cyl. area. again, ive pushed fluid both ways through the system now. even done the 2 man method with no luck. I wonder if you can bleed the system with the pedal down , with a pressure bleeder, but then that might not work becausse the check valve would be closed with the pedal down and no fluid should be able to go out to the slave. OR maybe that check valve is only for one way fluid. meaning, maybe fluid cant go back from the clutch slave, but it can go down. this way, i might be able to push the pedal down. air is entering the lines and then push that air out the slave with the pedal down. close the valve ,and pull the pedal up to position and it will draw fresh fluid from the reservior. has that ever been done??

Thanks!! This method sounds messy and almost impossible with the cage and race seat. hard to get contorted like that to work on that area of the car, but ive done it before when i had the brake /clutch pedal problem a few years ago. is there a way to get to the line coming off the master and birp it that way? meaning you loosen the line, and push the clutch pedal so that it forces whatevrer out of the master (hopefully air), then tighten the line. I will make a "hatch" to get to the master clutch cylinder, via the fender well, like we did with scots car.

IcemanG17

cutting a "vent" in the wheelwell to allow access is a great idea.....Casper already has one

Given the insane amount of effort to solve this I am leaning towards the master air bubble scenario....I would try taking it apart and burping...it....I'd guess its a pretty large bubble

Rob Edwards

How hard is it to remove the steering wheel and racing seat? Burping the CMC is a heck of a lot easier than trying to get to the outlet hardline (which isn't at the highest point of the CMC assembly anyway....)

Make sure you have a small pair of internal snap ring pliers on hand before you try to get under the dash.

mark kibort

not that hard. but still, a hassle. thanks for the reminder for the snapring pliers.

how is the burping done?? get the snap ring off, pull out the piston, and then what? Ill have to read up on the process again
thanks
Mk

mark kibort

the clutch gods must be back today........... did a pressure bleed at more like 12psi vs 5-8psi, and a reverse push bleed at 10psi vs the 5 psi used before. figured since i was going to need more fluid anyway after the bleed, why not push it up........ also , jacked up ONLY the driver side so it was higher than before (rather than both sides lifted). the pedal actaully felt a little better. 2" from the floor. so i rapidly started to push it in and out, and it felt faintly better, and then, all of the sudden, it overcame the spring on the pedal and snapped into position. a few more times and it was back to almost normal.

going for a ride to see if that fixed the original problem now that the crocks are gone ..................... drain the pond!

I have a feeling that this will be the solution....... however if im wrong, its going to make me sick! (need to balance clutch or replace master at that point) stay tuned!
Mk

the flyin' scotsman

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