Clutch Slipping - Only Sometimes!! ?????
 

I'm confused, and so is my mechanic. Here's the story:

I've had my 951 about 4 months. I start to notice that the clutch is slipping. I checked the records, and see that the clutch has about 58K miles on it, so I take the car to a local German garage, for a new ($2,200) Sachs clutch. He drives the car, and says he didn't notice any slippage. I figured, even if its not slipping all the time, it was about time for a clutch, so I had him go ahead and do it.

Now, I've had the car back for about a month, during which I have taken it very easy on the car, allowing the clutch to "break in". Sunday, I drove to church and back, about 30 miles roundtrip, and everything was fine. About 3 hours later, I get into the car to run to the store, and on my way, the clutch starts slipping really bad! I let it sit about an hour, then drove my daughter to the store, and it was still slipping badly.

I had to go out of town, so I had my wife drive it to the mechanic's. She didn't notice any slipping, but did notice a burning smell.

I talked to the mechanic today, and he says he drove it twice, for about 1/2 hour each time, and noticed no slipping.

I'm completely at a loss to explain what the problem may be.

Anyone have any ideas?

If I step any further out on this limb...

My first thought is that the clutch master and slave cylinders need to be bled. It can be a pain in the ass. If one of those components were not working correctly, it would cause the condition you describe. How about oil leaking from the rear main?

Oil leaking was the first thing I thought of. That could also explain the smell of burning oil. Since the rear main was changed when the clutch was done, unless that was done incorrectly, it should not be leaking.

I like the idea that the master and slave cylinders need to be bled: if we eliminate the clutch and rear main, it MUST be something else, like the hydrolics.

Thanks for the reply.

Anyone else want to venture a suggestion? Any and all are welcome....

I'll venture a guess... I previously owned a 944S about 10 years ago and had a similar situation. IIRC it was related to the master cylinder having been replaced recently. There was an adjustment to the pushrod/clevis that needed to be made that the mechanic did not do after he installed the new master, causing the clutch to slip when the car was at operating temperature. I took it somewhere else and they made the adjustment after diagnosing it, and it was fine thereafter. Clarks Garage has a detailed review of this procedure. HTH

http://www.clarks-garage.com/shop-manual/clutch-04.htm