Porsche 996 Supercharged C4 Clutch Replacement RennsportKC

When the supercharged C4 came in for a new belt and waterpump, the clutch pedal was occasionally sticking and the clutch was slipping. We put it off for awhile, but now the owner is ready to take care of it. I could tell immediately something was wrong in the rotating assembly, even though the owner didn’t want to believe it. I quickly shot down his slave cylinder theory as when a slave or master cylinder fails, the clutch pedal typically goes to the floor and will not come back. They don’t just leak and start to fail, the moment an air bubble gets in, or the seals tear and allow bypass, BAM no more pedal. A failed cylinder surely will not cause the clutch to slip, as the cylinder push rod pushes in on the clutch arm when operating the pedal, which then pushes on the pressure plate and removes pressure from the clutch assembly, allowing you to change gears etc. With the pedal at rest, the cylinder isn’t putting any pressure on that assembly to put pressure on the plate which would cause it to slip. Just doesn’t happen that way. Since this car has a SPEC clutch with 40k miles on it, the experience points to broken fingers on the pressure plate. Pretty common with SPEC clutches. Things got a little heated on this issue, but I wasn’t going to back down and waste the owner’s money on replacing the slave which I knew wouldn’t fix the issue. I’m by no means right all the time, but there are times I know I am not wrong 🙂 Some times you have to stick to your guns 😉

We had another issue to address as well….a badly leaking IMS/RMS seal.

The early EvoMS supercharger kit used a lower coolant tank for the intercooler cooling system. In the updated kits, they made a custom molded tank that fit nicely behind the front bumper bar. More stuff to get in the way when pulling the tranny out.

With the transaxle removed, we are staring at the pressure plate. Hard to see in this picture, but look closely at the pressure plate fingers.

A little easier to see in this photo. Broken pressure plate springs.

And you can see our oil leak issue below the clutch assembly.

Guide tube is pretty well grooved, so that and the armature will get replaced.


With the flywheel out of the way, there is a lot of oil leaking.

With everything cleaned up a bit, the old RMS comes out and the new one gets pushed in with special tool.

Sucking it in to the case.

And much better. Tomorrow I will tackle the IMS bearing. Hopefully I can get to the crankshaft to lock it out without having to pull the entire charge pipe system apart.

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January 17, 2013 at 9:32 PM

What brand of clutch do you use in these applications?


    January 18, 2013 at 8:57 PM

    Sachs power clutch 🙂

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