I've given up re my sticking clutch pedal

B6/7 S4/RS4
#1

So my clutch pedal is still sticking on WOT pulls.

Slave cylinder has been replaced
Master cylinder has been replaced
Line between the master and slave has been replaced with a ss braided line
Clutch assembly has been taken apart and put back together again with the release bearing replaced at that time.
Lines have been bled and flushed many times.

After all that, the pedal is STILL getting stuck after a WOT pull. I have to pull it back with my foot. While it’s stuck, there’s one inch of travel and in that one inch, the clutch is working just fine (i.e. grabs perfectly well). As I pull it back with my foot, it springs back into place and everything is fine again. In other words, it doesn’t sound like it’s a hydraulic issue (the pedal never feels soft and when it comes back from me pulling with my foot, it springs back just fine). It just gets stuck near the flooring (an inch away) and stays there but only after WOT runs. Normal driving is perfectly fine.

I’ve given up as to what the problem might be. No one else seems to be able to figure it out either.

#2

That sucks.

I know jack crap about the mechanics or hydraulics of our cars, never worked on them yet at all, but I think my first guess would have been the throwout bearing and fork for the clutch pressure plate. Had a similar thing happen with a clutch cable and the fork that released the pressure plate would get stuck sometimes because the pedal travel (cable pull) was actually a little too far. Just had to adjust the length of the cable a little.

But you said you checked the whole clutch assembly and replaced the bearing, and then again, the clutch is hydraulic so there wouldn’t be a cable holding the pedal down.

Wish I had some experience to offer any kind of worthwhile help.

How is the clutch pedal mechanically attached to activate the master? Something on the mechanical side that could be getting stuck maybe through the firewall?

I’m sure you’ve been through all of this and I am just repeating something you’ve already thought of.

#3

have you brought it to a shop?

#4

I would love to solve this mystery because it is definitely related to the stock RS4 sticky clutch issue. Just more severe.

Does the Jhm kit use any RS4 parts?

For what it is worth it didn’t stick when I drove your car and I definitely went WOT!

#5

I think the poor car has spent a lot of time at the shop (Twin iirc?)

#6

Really? It got stuck every time I went down the track. Did you push the pedal all the way to the floor or did you only push the pedal halfway down when you shifted? Maybe I should put some kind of stop behind the pedal so that it doesn’t go all the way down. Will need to do some tests. My point of friction is only halfway down so I don’t need to go all the way but when I’m WOT and shifting, it’s a reflex to push it all the way down.

Yeah, Twins works on the car.

#7

iirc it uses the stock rs4 pressure plate

#8

This was an issue with the Late moddle GM LT1 cars.

maybe we can dig this out. There is a good chance this is moddle related maybe.

I had this small issue on my B7 when I did the JHM clutch. After I checked the PP bolts *that I didn’t use loctight on and used a different brake fluid it stopped it. * I know I did something else as well.

Ive never heard of thsi on a B6… HMMMM

Will this do this on easy but quick shifts
Will it do this on easy but slow shifts.
Will this do this on a superfast shift but low RPM
will this do this on a super low shift on high RPM

Back in the day. The comarros would all do this if you upgraded them to a clutch with too high of a pressure plate ratting. You would need to get a new vac resivware.

The good thing is it isn’t sounding like a mechanical issue so much as a vac or hydrilic. Let me see if I can chat with a few older LS guys and see what we might be able to come up with.

#9

Good list of questions to have the information on.

#10

When I drove the car…

No
No
Dunno
What’s a super low shift on high rpm?

#11

I’m guessing he meant superslow…

#12

I thought you spoke fluent jfunkey. As SLVRRS4 said I think he meant super slow.

#13

Lol you got me there

#14

Basically, it doesn’t stick in any of those scenarios. It only occurs when I do a quick shift after going from low RPMs to high RPMs at WOT.

In other words, if I slowly take it up to redline and do a quick shift, it doesn’t do it. If however I go from 3k rpms or whatever to redline at full throttle and then shift fast, it sticks.

If I go from 3k rpms to redline at full throttle and shift super slow, it doesn’t stick (although it tries to a little but doesn’t due to the slow easy shift).

So it only occurs in ONE scenario. Fast shift from low to high RPMs at WOT. All other scenarios doesn’t stick.

#15

Check the reserve in the dydrolic line. Let me see if I can get a more specidic thing. This was just like this on the comarros. Its where the hydrolic system was over taxed if you reved the mtoor too fast.

#16

I made two passes at the strip in your car and I can shift pretty quickly and I also made a pass outside the track as well as a couple of rips through the gears and it didn’t stick once.

#17

Happens in my bone stock RS4 of you just rev the engine to 6k for fun sitting there at a light.

I think it has nothing to do with the clutch or flywheel. Fluid was my guess but I think Axel had changes his.

#18

Then you must not have started from a low enough rpm. Don’t know why else it wouldn’t have occurred. It happens to me without fail and I can replicate it any time.

#19

It’s been confirmed it has nothing to do with the clutch or the flywheel. The clutch continues to work perfectly. The fluid has been flushed many times. And the fluid is the same the brake fluid. If it were a problem, I’d most likelyfeel something wrong in the brakes as well, which are perfectly fine as well. This one is a dousy(sp?) guys.

#20

Looks like the LS1 guys have been having this issue for a while…
http://ls1tech.com/forums/manual-transmission/742741-sticking-clutch-pedal-write-up.html
Pages 1 and 7 are the most fruitful.
Other interesting info from link in page 7…
http://ls1tech.com/forums/manual-transmission/1513422-how-prolong-life-your-clutch.html

From what I’ve read I think this is a self adjusting pressure plate issue to which no one has really found a true solution to.

The first thing I’d try to do is make a clutch pedal stop. The engagement point well off the floor anyways. This is a long shot but reducing the pedal travel by say 15% may be enough to keep the damn thing from sticking on the floor. And if the pedal still sticks it will be easier to pull it back out again. Worth a shot?