Need help tracking down Pentosin leak - clutch
#17
02-08-2019, 08:49 PM
@lflouie i've spent 10 minutes trying to link the pic of the clutch switch jumper location at the pedals without luck. they changed how to post pics for some unknown reason. stupidly.
8 ball says try again later lol
add: once you jumper the switch, you'll no longer have failing accumulator and/or slave issues OR engagement point issues. assuming all internal clutch components are within "proper" spec.
8 ball says try again later lol
add: once you jumper the switch, you'll no longer have failing accumulator and/or slave issues OR engagement point issues. assuming all internal clutch components are within "proper" spec.
#18
02-08-2019, 09:21 PM
you're welcome. that pic btw was ( iirc ) contributed originally by gt2 rob.
it doesn't "FIX" anything. but, what it does, simply put. is to relieve the undue "stress" upon the accumulator. the juncture and component where all things on this rube goldberg hydraulic clutch system go south. eliminate the need to engage to clutch, and eliminate the usual issues. it takes 2 minutes, and when you start the car? it's like a "normal" manual trans startup. done in NEUTRAL lol
#19
02-09-2019, 05:03 AM
^^^^^THANKS for pic, that really makes it simple to locate.......I'll give it a try.
Reflecting on the OP''s original issue, I believe that the fluid migration is clutch slave seal related. As it fails/leaks, the pentosin fluid is transfered from pws side to the clutch master cylinder side.....and ultimately pushed out the top of clutch reservoir. This is what I'm seeing..... pws reservoir needs toping off and the clutch reservoir is full/overfilled.
The are several symptoms that are/can be present: 1) the fluid migration...with or without fluid under drivers side front of car, 2) stiff clutch at startup, 3) inconsistent clutch engagement point (worse than normal).
Based on all of the threads I've read and comments received or consistently mentioned, fluid migration is slave cyl seal failure/failing. The accumulator exasorbates a failing seal bc it's function is to retain pressure in the slave when engine is off, hence continuously pressurizing the seal. Ironically, if the accumulator has failed/failing and isn't retaining pressure it is not continuiously pushing fluid through the seal when engine is off....but of course it would have a stiff pedal at startup. Either way the root cause of the fluid migration is seal related and a matter of time before slave needs replacing.
The hard pedal at startup is most certainly caused by a loss of "preloaded"/pressurized slave cyl, but whether it is the accumulator failing (not holding pressure) or a leaking seal will require doing a simple set of tests. If there is a hard pedal but no fluid migration, the cause could be a failing accumulator...or a very slow slave cyl seal leak.
The third item, inconsistent clutch engagement, seems to be an annoying characteristic of the clutch/slave setup on the 997tt. Since I bought mine used, I don't have a known comparison....however it is inconsistent and drives me crazy. Everything I've read and found is that this system, even when new, has this characteristic. Replacing it with the GT2 setup, which isolates the pws from the clutch slave and eliminates the accumulator, or aftermarket solutions like BBI, which does the same thing, fixing the inherent slave/accumulator problem. The functional tradeoff is a stiffer clutch (which would be fine for me) and a more complicated ($$$) installation, but a more permanent fix.
Note: I'm a first time 997tt owner and my first Porsche, so I've been reading forums like this to gather info. Threads like this one have been invaluable as a training tool. Input, suggestions and guidance from other owners have all helped me to learn, diagnose and fix, repair or take corrective actions to prevent future problems. It is a great community of active owners!
Reflecting on the OP''s original issue, I believe that the fluid migration is clutch slave seal related. As it fails/leaks, the pentosin fluid is transfered from pws side to the clutch master cylinder side.....and ultimately pushed out the top of clutch reservoir. This is what I'm seeing..... pws reservoir needs toping off and the clutch reservoir is full/overfilled.
The are several symptoms that are/can be present: 1) the fluid migration...with or without fluid under drivers side front of car, 2) stiff clutch at startup, 3) inconsistent clutch engagement point (worse than normal).
Based on all of the threads I've read and comments received or consistently mentioned, fluid migration is slave cyl seal failure/failing. The accumulator exasorbates a failing seal bc it's function is to retain pressure in the slave when engine is off, hence continuously pressurizing the seal. Ironically, if the accumulator has failed/failing and isn't retaining pressure it is not continuiously pushing fluid through the seal when engine is off....but of course it would have a stiff pedal at startup. Either way the root cause of the fluid migration is seal related and a matter of time before slave needs replacing.
The hard pedal at startup is most certainly caused by a loss of "preloaded"/pressurized slave cyl, but whether it is the accumulator failing (not holding pressure) or a leaking seal will require doing a simple set of tests. If there is a hard pedal but no fluid migration, the cause could be a failing accumulator...or a very slow slave cyl seal leak.
The third item, inconsistent clutch engagement, seems to be an annoying characteristic of the clutch/slave setup on the 997tt. Since I bought mine used, I don't have a known comparison....however it is inconsistent and drives me crazy. Everything I've read and found is that this system, even when new, has this characteristic. Replacing it with the GT2 setup, which isolates the pws from the clutch slave and eliminates the accumulator, or aftermarket solutions like BBI, which does the same thing, fixing the inherent slave/accumulator problem. The functional tradeoff is a stiffer clutch (which would be fine for me) and a more complicated ($$$) installation, but a more permanent fix.
Note: I'm a first time 997tt owner and my first Porsche, so I've been reading forums like this to gather info. Threads like this one have been invaluable as a training tool. Input, suggestions and guidance from other owners have all helped me to learn, diagnose and fix, repair or take corrective actions to prevent future problems. It is a great community of active owners!
Last edited by lflouie; 02-09-2019 at 11:07 AM.
#20
02-09-2019, 10:41 AM
^ one of the most detailed explanations i've read onnthis topic. well done. i didnt realize the 97t shared this design "flaw". also i'm not at all sure that switch location would be the same but then, cant see how it wouldn't be either.
the whole point for me in having repeated/shared this info the nearly 100 times i have lol. is just to convey to those encountering this issue for the first? time themselves, so that they might learn of a "workaround" that neither requires time, money, energy or retro-fitting the clutch system to a non assisted gt2 setup, for the clutch to act as perfectly as it can be, and all the while eliminating the cause ( slave seal?? as you suggest or a failed accumulator ). again, pre switch jumping" i had been thru probably 4 accumulators in two separate 96t's! since the switch was neutralized years ago? none.
as a result, i have NO problem with the hydraulically assisted setup. now that i have No PROBLEM(s) with it lol. cheers.
the whole point for me in having repeated/shared this info the nearly 100 times i have lol. is just to convey to those encountering this issue for the first? time themselves, so that they might learn of a "workaround" that neither requires time, money, energy or retro-fitting the clutch system to a non assisted gt2 setup, for the clutch to act as perfectly as it can be, and all the while eliminating the cause ( slave seal?? as you suggest or a failed accumulator ). again, pre switch jumping" i had been thru probably 4 accumulators in two separate 96t's! since the switch was neutralized years ago? none.
as a result, i have NO problem with the hydraulically assisted setup. now that i have No PROBLEM(s) with it lol. cheers.
Thread
Thread Starter
Forum
Replies
Last Post
Yves
996 Turbo / GT2
3
03-07-2009 04:30 PM
