Cameron

Last week, I posted about a vibration in my clutch pedal when the clutch is depressed, the tranny is in gear and I rev the engine. The vibration that I feel in the clutch pedal is not through the entire rpm range, but is definately there between about 3k adn 4k rpm.

Advice is TO or pilot bearing possibly going bad. Not to wait to get the job done.

Today, I tried the same thing, but with the car in neutral and the clutch depressed. I have the same vibration in the clutch pedal. Whether I have the car in any gear, or in neutral, I can feel the vibration in the clutch pedal when I rev the engine.

Does this change the diagnosis? Sorry for my ignorance on the clutch setup / operation. I thought that I should cover this off before I make the investment.

Thanks

.....Cameron
'91 Euro GT

pewter82

how many miles on the clutch you have now?

jason

91GT

ErnestSw

The only time you'll usually feel the vibration is with the clutch depressed. Your further observations tend to confirm the diagnosis. When the pedal is depressed and the clutch is free wheeling it's supported by the bearings. When the clutch is engaged it's being spun by the engine and the vibrations will be damped.
"Pay me now-----or pay me later."

Garth S

If the trans shifts smoothly, clutch engages properly, and is vibration free under steady state cruise or acceleration - I would think yes.
As to 'making the investment', were you to open it up yourself with next day parts delivery available, then do so and look inside to confirm what is required prior to ordering - minimal investment.
If the job is done commercially, then the shop or mechanic's diagnosis is likely of more signifigance provided he is to stand behind the work (both in terms of correcting the issue and providing some warrenty term). The shop needs to have some ownership in the front end if they are to be responsible for the outcome.
Seeing and feeling the problem is usually better than discussing it - taking it in for a second opinion is the better thing to do initially, for it does not sound to be that urgent. They might charge for a diagnosis, might not ...
.

ErnestSw

Garth,
What does a Bluenoser know about Porsche clutches? It takes a Newfie ta figger out dem tings b'y.
I THINK you're saying that the smooth operation of the clutch and transmission tends to change your opinion about a bearing problem. With all due respect to your experience I disagree. However, I think we both agree that it should be dealt with ASAP.

Garth S

Ernest, Bugger all b'y, I wuz readin' the Chilton Manual in the lt'l outhouse t'other day!
Nope - no change of opinion! What I was saying (or trying to say) was that "yes", the orriginal 'bad bearing' call stands.
If the drivetrain operates smoothly with the clutch engaged (cruise/acceleration), it further points to bad bearings (as opposed to motor mounts, etc.): The bearings are only loaded with the clutch disengaged: If it is the release bearing only, one can happily drive off into the sunset, accepting the moaning [ like a bad relationship] when stepping on the clutch - and, in the extreme case ( which neither of us would do) drive on until it absolutely fails without grave consquence: the worse thing a failed release bearing can do is what? overheat the pressure plate fingers?, smush up the plastic release tube? - it is literally, connected to nothing.
If the moaning/vibration is at all due to the pilot bearing, then the consquences are more grave [now the bad relationship + a lawyer], and you have to pay attention now - sic " The Trials of Ernest - 'Pilot Bearing Replacement 101' "
In either case, both get replaced: One has more breathing time with a failing release bearing only: that is why a good on site diagnosis is better - if the pilot bearing is a primary cause, then replace ASAP - that being IMHO

Gretch

I still vote for the pilot bearing, the TO bearing would have to being pieces before it would cause vibration...........ask me how I know..........

Cameron

Thanks for the advice. I am in this car for the long term, so I have made the decision to do the entire job including pressure plate. If the old one is good, I will sell it used. I think that I can use GTS parts for additional robustness - who knows what future mods will bring in the form of additional HP.

.....Cameron
'91 Euro GT

Gretch

GT vs GTS clutch about the same... there is an updated release arm., I know that much......I am going to try a Kevlar disc next time I open mine up.

BTW if your pilot bearing is bad, don't let it go very long or you may have a hell of a time getting it out.....Ask Ernest..............

ErnestSw

Cameron,
When you replace your throw out bearing you'll have to replace the release arm as well since the newer (available) throw out bearings will not fit into the older release arm. You should also figure that cost into the job. The resulting upgrade will give you the GTS clutch if I understand correctly.