drodg

I am brand new to this forum and I just bought a 89 Carrera 4 with 27K on it and I have a question. My car is leaking brake fluid from a slave cylinder near the the transmission. I actually think it is just above the trans. It seeps out when I use the clutch. After driving it will cause a couple small puddles. My mechanic and I are a little confused on what it is actually is so I can order a new part for it.

Chris M.

The clutch slave cylinder is the one on top of the transmission and the part # 950 116 237 11 but I bet it's the hose that's leaking. That part # is 964 423 477 00 M33. It's possible that it just needs tightening but a 17 year old hose is probably pretty worn out by now. After fixing the leak, bleed the slave so there's no air bubbles.

c

Bill Gregory

You're describing the clutch slave cylinder, which is also where you bleed your clutch line. The clutch slave is a pretty basic 964 part, and if your mechanic doesn't know what the part is, how are they going to handle something more 964 complex? You may want to consider finding a mechanic more experienced with 964's. I think you'll find the part you want is Porsche part number 950.116.237.12, the clutch operating cylinder.

edit: Chris raises a good point on the hose too. You may want to remove the left rear wheel and have someone work the clutch pedal, and look for the source of the leak.

drodg

We don't have a repair manual other than the one by Adrian Streather. I may be wrong but he didn't believe it was the cluth slave cylinder as it's closer to the front of the trans and above it. I thought the clutch slave cylinder was farther back.

Chris M.

In this picture, the arrow points to the hole where the slave cylinder pushrod goes inside the transmission to make contact with the release fork. The bolts above and below the hole are where the slave is attached to the transmission. The front of the car is to the left, rear to the right and the engine would be further to the right. If it's not this cylinder or the hose that's leaking then it could be one of the differential slave cylinders on C4s and for more info on that you'll have to hope Garrett376 sees this thread.


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drodg

Well after some research this is the part that appears to be leaking. The Longitudinal Diff Slave cylinder. I could use a part number and some type of schematic to get to it and replace it. Thanks for everyones input.

Chris M.

"garrett's C4 engine drop thread"
Scroll down and Garrett talks about removing the PDAS cylinders. I think this is what you're talking about.

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drodg

Thanks for the info. I sent a private message.

garrett376

Hi Guys!

It sounds like it's the longitudinal, or axial PDAS slave cylinder what is leaking - part number 20 in the PET diagram below. These things can either themselves leak (in which case it's brake fluid) or the sleeve can go bad so gear oil leaks. In the case that it sounds like brake fluid is the problem, the diagram below from the PET shows not only the part, but also the part number to replace the slave cylinder itself. Its replacement is not difficult once you've got the car high up in the air, with the under panels off. It requires the removal of one hex screw which frees up the fork shown below. Sometimes it's difficult to coerce that thing to come out. Once the fork slides out, the slave cylinder is free except for the hard hydraulic line that holds it. If you are replacing this, you have to undo the line anyways. So remove the line and then out comes the slave cylinder.

After replacing the slave cylinder, you'll need to bleed the PDAS from the solenoid block to the slave cylinders, which requires the Hammer. If you have no way to access the Hammer, you can bleed the system by using the PDAS interlock switch on the center console: turn the switch on to pressurize the cylinders, then open the bleed screw. Turn it off, the repeat until no more air bubbles comes out.

The pictures below show the slave cylinder and its removal. Hopefully that helps and gets you back on the road!

drodg

Garrett thank you very much this is exactly what we needed. Dave

drodg

to everyone esp Garrett for helping me on this brake fluid leak. It was the longitudinal slave cylinder and I ordered it from Porsche and had it replaced as outlined. thanks again

TR6

Is the procedure to bleed or replace the slave cylinder in a C2 different than the C4 procedure described here?