SmokeyBear2001

I need some troubleshooting help!! I have a 2010 Rubicon with 47000 miles and a six speed manual transmission. The slave cylinder started leaking inside the bell housing. I took it to a jeep dealership to get the cylinder replaced. New cylinder blew out before it ever left the place. They went through three cylinders. Believed it was something with the clutch assembly. Broke the engine apart from tranny and replaced the clutch assembly along with TOB and Pilot bearing. The slave cylinders were blowing out because the ram or piston was traveling to far out from the cylinder. Thus the it's something with the clutch leaning toward the TOB.. So they put it all back together and blow out another slave cylinder.. They replaced the master cylinder and put in a new slave cylinder and any guesses??? Yep blew it out. The dealership has no idea..

Is there anybody else that has had a similar problem and if so how did it get fixed? I thought maybe there was something with the clutch peddle being out of whack and traveling too far allowing too much fluid into the cylinder forcing the slave to extend too far thus blowing out the o rings around where the ram meets the cylinder body. Any help would be greatly appreciated. Because at this point the only stuff that has not been replaced is the clutch peddle and the line between the master and the slave. The line is good and fluid flow is good between the two.

Mark Doiron

Slave cylinder "blowing out"? I've never heard of this before. Doesn't mean it's not so, but how have they determined that it was "blown out"?

Anyway, what I have seen is folks swapping out the clutch slave cylinder overlooking the oddly shaped O-ring on the end of the fluid line. It can easily fall off, is made of something similar to Flubber (TM, Disney), and will bounce under some workbench in the blink of an eye. If the installer fails to notice this, then he/she could replace the clutch slave cylinder a thousand times and still have it leaking every time the pedal is pressed. If missing, you can get a new one by picking up a new fluid line. There is one of these special O-rings at each end, BTW. It is not a normal looking O-ring, and cannot be picked up where you'd pick up normal looking O-rings. Just buy the line, if that's the problem.

https://www.4wheelparts.com/Drivetra...RoC9AgQAvD_BwE

Edit: Note that I know the OEM line comes with the O-rings. Not certain about that line from 4WP. Perhaps someone can chime in, or your local store can clarify for you. Or just order it, then check for the O-rings before you leave the store.

SmokeyBear2001

When the cylinder is activated, the ram or push rod is traveling to far out. Pulling the rubber dust boot off and causing the cylinder to leak "blow out" around the o rings where the push rod comes out of the cylinder body. UPDATE!! Dealership says they have it fixed. Apparently I misunderstood them and they had not replaced the master cylinder. They replaced the master cylinder and the slave cylinder is holding with no problems and operating correctly... A little perturbed that it was figured out after replacing the whole clutch assembly to the tune of 1600.00. Which apparently had nothing to do with the problem...

Chuck-The-Ripper

I had this problem a couple years ago, it sure as shit didn't take me that many times to figure it out though. That's insane.
If there's nothing stopping the plunger from over extending, it will do just that, over extend. The plunger sits in a socket on ones side of the clutch fork while the other side of the fork rests on a "ball" inside the bell housing, with the TOB in the middle riding on the input shaft. My problem was a blown up TOB, but given they replaced yours it's either on the input shaft wrong, they have it reversed on the clutch fork (backwards) or it's not resting on the "ball" opposite side of where the plunger sits in. It shouldn't be hard to recognize if you were looking at it (and knew what you were looking at)

Jeepnfamily

Thanks for this thread. Having same problem on my 07 JKU. Have gone through platic Amazon slave, 2 metal O'Reilly slaves, and now a plastic AutoZone slave. Same problem. When we try to "bleed" the clutch slave, fluid begins shooting out the end. Basically blowing the seals out of the slave. Having a hard time believing I got 4 bad slaves.

I have replaced the master as well. Only thing not replaced is the lines between the two.

Did dealership ever day what the problem was or how they fixed?

Grecy

Anyone else have this problem or find a new way to resolve it?

Exactly the same thing here.. I put in two new slave cylinders today, both times the pedal starts to get firm and then they "blow out", and brake fluid sprews out around the bell housing where the slave is bolted in.
I pump the pedal maybe 10-20 times and it's very soft, then slowly starts to get firm... about what it should feel like (i.e. not crazy hard to push).. and then it pops. I'm not pushing harder on the clutch when it happens that I normally would.
I open it all back up and sure enough the boot has come off and oil is leaking out around the over-extended plunger.

My only thought is that I'm not getting it lined up properly when it's going in (hard with the transfer case cable in the way)... so then the punger doesn't seat into the fork correctly.
So twice I tried *really* hard to get it straight and good... and same result.

I had an entirely new clutch and TOB installed about 50k miles ago, and I can't imagine the TOB or fork or ball on the other end have suddenly gone bad for no reason, but I suppose it's a possibility and they're stopping the plunger from being able to push the fork correctly? I don't really buy that though, because a few times while pumping the pedal the clutch makes it's same old creaky noise so I think at least for a few pumps the plunger is actually operating the clutch.. until it pops without using excessive force.
It was all working fine and the pedal started going really soft and taking up very close to the floor.. also oil leaking from bottom of bell housing which lead me to the slave.. but now replacing it I just keep having these "blow outs".

Any other ideas? I really don't want to open up the clutch...

2011 JKUR when the clutch was done everything was OEM parts from a dealer.

-Dan

Grecy

I'm updating this in case someone else has the same problem... but sorry, I don't know how to fix it.

After trying to replace the slave myself repeatedly and it was always overextending I gave up.
I drove it to a shop - I just drove in 1st gear and turned the engine off when I needed to stop. It starts OK in first or reverse, I didn't try 2nd.

They pulled everything apart and said it was all perfect, so they put it all back together and put on a new slave and it works perfectly.
So I have no idea what I was doing wrong, but apparently I'm not qualified to do it.

On the plus side they also did the rear main engine seal which has been leaking for a while, and said the clutch looks almost brand new, so I know I'm good there.

Good luck if you ever have the same problem!

-Dan

CC172

Reviving this thread as I have the same issue. Blew out my slave cylinder and attempted a field repair. As we were bleeding the hydraulic system the clutch pedal would get stiff and then over extend the slave cylinder and blow the seals. This happened twice with two new slave cylinders, said ‘F-It’ and towed it home. Now I’m about to dig into this again and before I just start breaking good parts again I’m trying to fix what is actually broken. I don’t think the clutch is bad but not ruling that out entirely. I can rock the jeep in gear and bump the engine over so it’s not directly the clutch. Is there a special trick to bleeding the hydraulic systems? Can the Master Cylinder be contributing to this problem?

Thanks!!

VENOM_JKUR

I have been working on my JK for the last week….. I have put in three separate units with the same result each time. Could I be possibly not aligning the slave when installing? One time I was able to is tap and have plenty of pressure drove a few miles and then started leaving through the bell housing again. The boot is still connected to the plastic cap. I know on all data is days don’t rotate more than 3 degrees what is the reason for this? Could it be just not setting into the cup on the arm properly? When it did have pressure it shifted no problem and I can start it in reverse or first and if I rev match it I can shift into any gear (yes I know this isn’t the greatest thing to do for the transmission) but at this point I’m am desperate for any possible advice I could be given for what I may be missing, thanks.

CC172

I just got my jeep back up and running. The issue was the throw out bearing., it was completely trashed. I bought the jeep used and prior to buying it the previous owner made mention of installing a new clutch. Well I can now attest that he did a clutch replacement, ground the flywheel and installed a new pressure pressure plate. However, the part they skipped out on was not replacing the TOB. The frustration you have knowing someone cut a $50 corner while they have their vehicle in pieces is extremely frustrating. I smoked 2 slave cylinders before I threw in the towel and took everything apart. It sounds like you have the same issue. Only difference is my TOB was completely toast. It came out in two pieces, had parts of the ball bearings lying in the bottom of bell housing.

FYI.... there's another good thread talking about replacing the clutch and TOB. There is also a service bulletin to shim the TOB fork ball.

Good luck!