Clutch pedal stuck after WOT pull to redline

[heartmys4]

After installing an ECS LWFW + Sachs XTend clutch a few years ago, I started getting some weird behavior with the clutch pedal sticking to the floor after doing a WOT pull to redline. It started out happening very infrequently (maybe 10% of pulls), however it has reached the point where it happens almost every single time.

It doesn't matter what gear it's in - if I start low in 1st gear or in 4th and go WOT all the way to redline, the moment the clutch is pushed in, it stays stuck to the floor. It doesn't matter if the shifter stays in gear, moves to neutral, or shifts to another gear. If I push in the clutch early (say, around 4-5k), this doesn't happen. If I rev out to 7k very slowly (not WOT), this also does not happen. It only seems to happen with a WOT pull to redline.

Once I manually pull the clutch up with my foot, everything is back to normal. I can shift again as if nothing happened.

My first guess would be this is a sticking throwout bearing, but I would expect to see this occurring outside of just WOT redline pulls if it were. It doesn't make sense for this to be a SAC/slave-rod issue, because I haven't once had the push-to-start issue.

I do still have the clutch delay valve - could that somehow be sticking?

[Jay@JXB]

It’s either your TOB, or it’s the friction insert on your flywheel (warps when hot), or it’s clutch going (fingers can get weak when hot). For me it was the flywheel insert. I switched to the Clutchmasters LW steel one (only a couple lbs heavier without the headache).


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[heartmys4]

or it’s the friction insert on your flywheel (warps when hot), or it’s clutch going (fingers can get weak when hot).

Oooh, that makes the most sense to me. Could it be that only some of the fingers get weak when hot causing uneven pressure on the TOB, and that makes it kink on the shaft and stick?

[Jay@JXB]

Possibly? It’s more likely the friction insert honestly. Those things are trash, and they all come from exactly the same place regardless of brand. Mine warped so bad it broke one of the retaining bolts. We had exactly the same symptoms. Car was fine driving up to the Autocross start line. Launch, then the 1-2 shift returned slow. Stay in 2nd for a minute of racing and when we got back the pedal would stick to the floor. 5 minutes later back to normal again.


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[wes8398]

Paging Jay Bullingt............nevermind. [emoji3516]