clutch vibration

The other day my clutch pedal started feeling funny. At first, I thought it was slipping and was thinking I was about due for a new clutch kit. Now, I'm not so sure. I have been paying particularly close attention to it lately and it is not slipping at all. The pedal just vibrates when i depress it. It seems worse at the top (when I just start to push it). Any ideas what this could be? It is driving me crazy because it really throws off the "feel" of the clutch. TIA...

how is your brake fluid level?

Seems good...right up to the "Max" mark.

Go do a search on the 996TT forum...this subject has been discussed there quite a bit. I've researched it quite extensively and have talked to Porsche about it. Most of the Porsche mechanics who have driven the car as well as the indy's I've had drive it say that it feels like the "fingers" on the clutch that vibrate at certain rpms...in my case around 3500-4000 rpms. The "experts" have told me not to worry about it and that it is something that occurs often in cars....even one guy who drives a cobra said the same thing. My only concern is that it might be tied to a part of the clutch that would be covered under warranty....and my warranty is due to run out at the end of August this year. Go do a search on the 996TT forum for "clutch vibration".

clutch release bearing

i asked my dealer about the vibration as well. I felt it as I depressed it, right at the top....he said it's normal....something with the flywheel. I have put 20k miles on the car without any tranny issue....knocking on wood... J

or master or slave clutch cylinders.

Mine has not always done this...only started a week ago. Before, I really liked the clutch feel and now I have a hard time getting a feel for it. The vibration is pretty severe. It vibrates the moment the clutch is depressed even the slightest bit (1/4th inch). It does it in any gear and in neutral. Anytime the pedal is depressed...moving or not. I guess i'll take it to the stealer next week and have someone drive it to see what they think. When i called, the tech said it sounds like a TO bearing. He said that would require an entire clutch replacement ($1000 labor and $400 to $500 for parts).

It could be your TO bearing...but in my case, it only started vibrating at 3800-4000 rpm. Like yours, it's only really noticeable as you barely put pressure on the clutch pedal as you start to depress it.....like you said, maybe a 1/4 inch of pressure...then you feel the vibration in the ball of your foot. Everyone I talked to said not to worry about it....but in your case, if it does it in all gears without being under acceleration, it could very well be the TO bearing. Typically, they replace the entire clutch assemply when they go in to do a TO bearing....and my last quote for the whole thing including parts was $1200....so at $1500 you might be a tad bit high. If you contact Sunset Imports and price out a clutch assembly, you'll find a BIG difference in what the dealer charges you for a Porsche clutch as opposed to what you can buy one for....but they usually refuse to install a clutch that you buy on your own....or they put a caveat in there that if something goes wrong, they won't guarantee the work kuz you bought your own parts. If you know a good indy...just buy the clutch assembly and have him install it...you'll come out much better than a dealership.

FYI: Drove my 997S today with a Porsche factory rep, who says the clutch buzz/vibration in my pedal at the higher revs is normal and caused by the pressure plate vibrating for that split second between shifts. He claims the factory does it that way to reconcile the dual desires of 911 drivers who wish for performance with everyday driving. Stated in a different way, he said, if the factory engineered the clutch so tight as to avoid the annoying vibration, it would last only half as long before wearing out. MIND YOU, THE FACTORY REP SAID THIS, NOT ME. I'm acting as messenger. I'm interested in your opinion.

Quotes source post: 5589923

Sounds like a load of BS.

The same thought occurred to me, although it sounds as though M Fig''s clutch vibration is far worse than mine. The buzz I'm feeling in the pedal is not a heavy one like his, which is why I call it a buzz and not a vibration, and it doesn't occur with all shifting. Nevertheless, it bugs me. BTW, the dealer replaced the throwout bearing when I first complained of the pedal buzz a month ago, and it eliminated part but not all of the clutch pedal buzz. For more on my experience, read the thread I posted in the Rennlist's 997 discussion area a few weeks ago titled "Clutch Pedal Buzz". What other recourse does a 911 driver under warranty have when the factory says NO WAY?

Could be a number of things. Throw out Bearing to a seeping touch of oil on the clutch

How does the oil translate into a vibration and how do you get oil in the clutch if the transmission hasn't been pulled?

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If you have a tad (small) amount of oil that has gotten on your clutch it may slip as the original poster stated he was feeling. I'm not certain about the vibration sensation he is feeling at initial engagement of clutch, could be a bad pressure plate, throw out bearing, who knows until you look. Only mechanic with a test drive and/or dropping the transmission will know. Seals have been known to leak oil, in particular, the seal where the flywheel is bolted to your engine and collect in bottom of the bell housing waiting to be thrown around. I know it is hard to believe, but I've heard it happen before.

If I understand you correctly, you need to replace the clutch. It is an issue of the T.O. bearing and the pres plate.

The throwout bearing was replaced two weeks ago. I might need either a pressure plate, clutch plate, flywheel w/ pilot bearing or all three. Or, was alluded to by the Porsche factory rep, I might need to suck it up and just enjoy the car, clutch pedal vibration and all.

Whenever the fingers on the pressure plate change plane, they will make the throw-out bearing bounce a little causing a slight vibration. It only takes thousandths of an inch. Fairly normal to me on all the manual cars I've owned.

sounds like the pressure plate. does the vibration frequency change with engine speed?

In my case, the vibration only came on at 3800-4000 rpm....but just recently, the clutch became very hard to depress in order to start the car....so I ordered the accumulator. Unfortunately, the accumulator is not covered under CPO...however the slave that it attaches to is....so figure that one out. I'm hoping that the problem has been related to the accumulator all along....I'll know this next week after the fix.