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View Full Version : Intermittent clutch failure on new master-slave-line components



///Manuel
08-29-2009, 03:10 AM
Resolved: Culprit = Pressure plate! See "EDIT3" down below.

I have recently updated all clutch components and I'm getting an intermittent clutch master cylinder failure. The pedal gets stuck to the floor, I need to pull it back up, pump a few times and eventually it gets firm enough for me to start using it again. If I don't use it for a few seconds then it will fail the first time I use it :nono so I try to keep pumping it until I get home.

It happens when warm and doesn't when cold. I bled lots of fluid out about 1.5 quarts overall through vacuum bleeding, manual bleeding and power bleeding (spent days on everything) and it's still happening. By hand (two-man method), the pedal will get firm and then randomly all of a sudden fail. When it does fail it makes squirting sounds right within the master. I tried pulling the slave out and pushing the rod back in multiple times :help

I'm really puzzled and wonder if there could be any be air still in the system or that maybe I got a defective master cylinder?

EDIT: After another test drive, I was able to reproduce the problem and felt the pedal when it happened again. By feel I could tell that there's still was air in the system, the master felt soft and mushy, pumping got the pedal somewhat firm again.

So I went back home and raised the rear of the car as high as my jack would allow (in hope to have bubbles come up from the slave) and pressure bled once more.
After a few ounces of fluid came out, I disconnected the bleeder, pumped the pedal and finished with the old pump and bleed process. I'm not sure I could tell whether there was any difference in terms of bubbles but I could feel the pedal get a touch firmer.

Finally, I went for a ride and voilą, no more problem, a firm pedal whether warm or not, smooth shifts, I have my car back, what a b*tch... I smoked what I think was a Stratus R/T for good measure even though he had the jump (I wanted to give him a chance :)) as I was entering the highway, it feels great to have my car up and running 100%.

EDIT2: Just when I thought it was sorted out, after a flawless 200-mile drive to Aspen, my clutch went out again! I was able to pull over and bleed it when I ran into the "squirting sound" again. This time I was able to see that fluid was being spitted out back into the reservoir and lead me to think that the lower seal in the master was bad. By using the clutch very slowly, I was able to drive home ok but I'm now pretty sure that the master is defective, I'll be replacing it shortly and update this thread. What a pain :eyecrazy

EDIT3: I got the master replaced at the dealer under warranty, that one never failed but felt mushy as well. So I decided to replace the clutch, throw-out and pilot bearings. That fixed the problem. The pressure plate must have been defective. The clutch pedal now feels nice and firm, it also fixed a gear rattle that the car has developed at idle. I can now feel the car bite between gear changes, so phenomenal!

juvius
08-29-2009, 03:47 AM
two things come to mind....

one, you my have a kink in the line. the force of the pedal could be pushing through the kink (could be causing the squirting sound), but when you left off the clutch there isn't enough force to push back up...

or the other:
double check that the master cylinder isn't leaking.... sometimes you can't see the leak until you look under the carpet..... sounds like you thouroughly got the air out, and if you hear squirting and there is no kink, fluid must be going somewhere.... has the fluid level gone down?

p1zz4guy
08-29-2009, 03:53 AM
Did you use a pressure bleeder or just pump and bleed? (like what you do for brakes). When I replaced my slave and master cylinder I tryed to pump and bleed and had a hell of a time and had to take it to a shop to have them pressure bleed the whole system.

///Manuel
08-29-2009, 04:04 AM
I pressured bled a quart last, clear fluid with no bubbles was coming out but it doesn't mean that there's no air left still (what a b$tch honestly).
The kink I guess is a possibility but wouldn't happen as randomly as it does, would it?
Ever since I replaced the master, I got that phenomenon.

juvius
08-29-2009, 04:09 AM
your probably right about the kink... heh after 4am and still can't sleep.... but the squirting sound.... have you check inside and out for a leak? reason why i say look unde the carpet is because i had a car that was bled and couldn't keep a good pedal... looked and looked... inside and out was dry until i looked at the carpet.... it was squirting just so that it was hitting the top edge and soaking in. took me frever to figure that out... and yah... there could be air, but sounds like you've already bled the hell out of it....

///Manuel
08-29-2009, 04:20 AM
The squirting noise sounds like is coming from inside the master as it fails.
No leaks anywhere. Now that I've bled it with the power bleeder maybe I should give it some more two-man bleeding to really push it all out.

juvius
08-29-2009, 04:23 AM
did you prime the master cylinder before you installed it? heck i don't even know if that matters as much as you've bled it...

///Manuel
08-29-2009, 04:39 AM
No I didn't prime it. The weird thing is that it would have to have a big bubble to fail like it does, I don't know... I'll try the two-man bleeding because it was push fluid out with some force and see what happens then. The powerbleeder doesn't really push much (I had it set close to 15 psi).

juvius
08-29-2009, 04:46 AM
i hope that works out for you... it'd be a pain in the butt to have to take the part out, return it, reinstall and go through bleeding again....

ross1
08-29-2009, 08:00 AM
The master is NG

gtopaul
08-29-2009, 08:20 AM
The master is NG

I agree. Did you replace it?

zubbie
08-29-2009, 08:37 AM
Bench bleeding is a must for any master cylinder (although me thinks you will have likely gotten all the bubbles free by now)

My guess is also a bad master. Some masters are "rebuilt" by boring the cylinder bigger and inserting a larger diameter push rod and seals. This process does not guarantee removal of the internal pitting caused by old, caustic, water filled fluid. Thus masters fail right out of the box.

GL

///Manuel
08-29-2009, 01:52 PM
Coming to think of it, I did add fluid to the master prior to install.
I will contact the vendor (BMA parts) and hope that they can help me out.
What a drag on that one.

///Manuel
11-25-2009, 05:14 PM
Bump for a resolution! See first post.