Olitho

The car:

• My 2002 C5 Z06 T1 car
• The clutch, flywheel, throwout bearing, slave cylinder, et al are all stock hardware

The problem:
My clutch does not start to disengage until about 1/2 down the throw.

It starts to reengage shortly after letting it come back up. 1/2 the throw distance seems to be dead.

Practice starts Friday afternoon at Auto Club Speedway with qualifying starting Saturday AM.

The clutch has been bled, almost a whole bottle of fluid through the system.

Any ideas on where to begin first in order to save time?


Thanks,

Oli

rasrboy

Well, you bled the system and if its still the same I would try a slave or master next. I would do slave first and see what goes. How many races on the clutch, could be getting down there too.

Maybe Popp will see this and chime in since he is the master at this stuff.

Good luck this weekend Oli.

Aaron

travisnd

If the clutch return spring is still in there get it out. It'll make a marginal clutch hang up.

redtopz

I saw you had some trouble shifting in your ACS video and I was wondering why. All I can say is if I were you I would be pulling out my clutch today and installing a new slave cylinder and inspecting the clutch, flywheel, and throwout bearing while I'm there. I've had a master cylinder fail on my LS2 gto, but when it failed the hydraulics stopped working completely. Not sure if a partial pedal would point to the master cylinder or not. Hopefully John can help you get this done today. I can't get down to ACS until Fri afternoon and I hope to get my annual tech at that time. See you there and good luck!

Bill.

RX-Ben

Did you do the basics first?
- replace fluid? (if you have a remote clutch bleeder)
- if no remote bleeder - replace the fluid, pump x 40, replace, pump x 40, replace

Has the car been sitting? If so, hopefully just an air bubble or some water in the fluid.

Olitho

No, the car has not been sitting. I did bleed through a bunch of fluid.

No time to change the clutch hardware out right now, but I did order all the required parts in case we need to pull an all nighter before the big race on Sunday.

Practice is tomorrow afternoon with a regional race and qualifying on Saturday.


Thanks everyone for your suggestions,

Oli

RX-Ben

Careful if high rpm shifting is notchy/heavy!!
That means you are toasting/have toasted your blocker rings b/c the clutch is not disengaging.
Ask me how I know!

mgarfias

Just shift without the sucker.

gkmccready

Not a Corvette, but my Miata behaves like this when the clutch slave lets go... in fact, it's behaving this way right now after sitting for a while and the clutch was perfect when I parked it...

sothpaw2

I've found it does make a difference as to what brake fluid you use when you do the clutch through the reservoir. Use Castrol SRF. I would flush, drive car, flush, drive car, 8 times. When you drive it, shift frequently, but no high rpm shifts. I think this mixes the fluid much better than just pumping the clutch pedal while stationary. This is much easier done on the street. Certainly before and after your qualifying run I would flush with fresh SRF.

I've used Motul and before that Prestone and the pedal hangs up a bit as you describe. Not so with SRF if I change it out several times per day during a typical HPDE day.

Olitho

The problem is now fixed. I thought it was going to turn out to be the slave cylinder.

We swapped out the clutch hardware tonight. Three of the bolt holes on the pressure plate were cracked through the flange. We replace that piece of hardware as well as the clutch plate, slave cylinder and throw-out bearing and she shifts smoothly again. I have my first qualifier in exacty five hours. Time to go to bed... but we already disconnected the rear sway bar as it is almost certain to be raining.

Many kudos to Mike, Nick, Christian and Adam at Competition GT in Costa Mesa. They threw my car on the lift today at about 6:30 PM tonight to get this job done quickly and with the right equipment. Doing this at the track would have been next to impossible.

Competition GT Rocks!!! Thanks guys!


Oli

J.R.

Oli,

Good luck.

We have 7 NASA race weekends out here this year. Your car would transfer over to ST2 easily. Your driving easily makes up for a little aero.

The offer still stands.

J.R.