Having some problems with my 06 Z06 not wanting to go in gear after a drag strip pass. Car has a mantic 9000 dual disc with oem hydraulics, brand new master cylinder when installed about 4k miles ago.

I've been driving the car all summer and have made a few track trips without issue. I went out for some test and tune this past friday and all was perfect up until my last pass. I launched the car hard spraying nitrous out of the hole, made it back to the pits and shut the car off, everything seemed normal. When I started it back up to leave for the day, the car didnt want to shift into gear. I finally got it shifted and drove home, shifting was a bit notchy the whole way.

Yesterday I jump in the car and go to back it out of the garage and it still doesnt want to go in gear. I pull the mgw shifter and check for alignment, no problems there. Then I notice as I try to shift it, the car wants to bump forward or backwards ever so slightly. It looks like the clutch isnt totally disengaged with the clutch pushed in. If I start the car in gear it will bump forward a small amount but doesnt take off or anything, just a small bump. Comes out of gear no problem but then has a problem going back in.

I've spent the past day and a half reading every thread on this I can find and most have this problem on a new clutch install, not out of the blue or after some spirited driving. I tried bleeding the clutch with the remote bleeder and pulled about 3 reservoirs full of fluid through it but it almost seems like that made it worse. Clutch pedal pressure feels unchanged as far as I can tell.

Is it more likely hydraulics related or could I have broken hard parts? Before I go tearing into the car I was looking for any other possible checks I can do, any help would be appreciated.



Side note - Dont know if this is related or not but on long distance cruising on the highway, maybe 20 miles or so, the clutch pedal would sink over time....I'd end up having to pump it up before taking and exit so I could shift. It was only on longer drives and I never really thought about it too much but now that I'm having these issues.....

 

Is it still the factory release bearing retainer or the monster billet one?

 

Clutch isn't disengaging. Yes, the pedal sinking down is related.

How does the pedal feel? Normal, soft, spongy? Any fluid leaking anywhere?

Good question.. is it using a factory slave or was the bearing support replaced with a billet one? The stock one is plastic and will melt under enough heat.

 

The slave and its conponents came with the mantic 9000 kit. Didnt even know monster made a billet piece.

No fluid leaking anywhere that I can see, resevoir still at the same height as when I parked it yesterday. Pedal firmness feels the same, no change as far as I can tell.

On the first clutch push and hold its difficult to get in gear, once it goes in with the pedal still pushed it goes in and out of gear with minimal effort. If I then let the clutch out and push it back down it is hard to shift once again.

Its got to be dragging ever so slightly because it doesnt move with the pedal down and in 1st gear, modulating the clutch and its engagement point feels normal as well.

 

When bleeding through the remote bleeder, are you closing the nipple after each press down?
One time I attached one of those one way ball valve hose for one man bleeding, but ended up with a poor bleed, I believe due to air going back in through the threads of the remote bleeder nipple.

By getting out and closing the nipple after each press down, before lifting the pedal back in to fill with fluid fixed that problem.

Better yet, I guess a 2 person bleed makes it much easier and ensures no air intrusion, if you have an extra person to twist the wrench or press the clutch.

 

I bled it yesterday with a mightyvac on the remote bleeder. Just put a bit of vacuum on it and let it it slowly draw the fluid through the system. Im gonna give it a bit more as I dont think I fully got it all flushed.

I gave it a ride around the block just now and it doesnt feel as bad as driving home friday night. I havent really driven it since bleeding it the other day, just shifted it a bit in the driveway.

 

One last bit of info;

Went out there just now, with the car in first, motor off and clutch pushed in I can use my left foot out of the door and push the car but it takes some effort, clutch is just barely hanging on. Start the car like this and it rolls freely.

 

Anyone else have a suggestion before I go ripping the car apart? I have a tick master sitting around that I think im going to swap in to rule out the oem master. Easiest thing I can think to do at this point.

 

That's what I would try first..

 

I also use the mityvac but suggest a 2 person pump job the best to finalize the bleeding. I bleed mine often but found it best to at least manual pump it last shot rather than use the vacuum. I experienced a similar issue to yours

 

That makes me feel a little bit better. I dont recall any problems shifting coming back down the return road, I'll grab my neighbor and see if I can give it a 2 man bleed before swapping the master. How similar to my issue was yours?

I did run it hard these past few months but after 4k miles and two dozen or so strip passes I cant imagine its cooked.

 

well I noticed the clutch grab a little different (higher) and harder shifting. Got my friend sebast19x to help bleed at the track and instantly felt better. I drove 4hrs to get there and it felt fine, it's when I started to push mine I noticed something wasn't 100%