UstaB-GS549

I have been having trouble with clutch not fully releasing in my C5 Z06 with stock engine. It's got 30k miles and this is my 8th season of DE & TT events. It did this twice last year and went away, but now it seems permanent.

Wednesday night I installed a new Tick adjustable clutch master cylinder and it seemed to eliminate the clutch not releasing completely at idle. For any number of reasons, I did not get it buttoned up until yesterday. Once again, I could not get shift lever into any gear at idle. A turn or two on the adjustment turn buckle solved that..... but

At this point it feels like the clutch take-up point is a lot higher than before and also it does not take much travel at the top to slip the clutch when cruising in 4th at 30 MPH. If I floor it and jump on the brakes at the same time, I don't get any slippage.

My take on all this is that something is wrong with the pressure plate clamping evenly. It takes almost full MC stroke to release it fully , but yet does not take-up at the normal point.

I'm going to Road America next weekend. Should I look for someone who can release clutch this week, or just go as is?

sperkins

Stock clutch?
You may have broken a tab off of the pressure plate and it's hanging up in the fingers. I've seen this several times. Pull the inspection cover and look for anything unusual. This clutch has 6 broken tabs (outer perimeter near disc). One of them got wedged in the fingers of the pressure plate and caused problems getting the car in and out of gear.



And one of them went clean through the inspection cover.

UstaB-GS549

[QUOTE=sperkins;1578915039]Stock clutch?
You may have broken a tab off of the pressure plate and it's hanging up in the fingers. I've seen this several times. Pull the inspection cover and look for anything unusual. This clutch has 6 broken tabs (outer perimeter near disc). One of them got wedged in the fingers of the pressure plate and caused problems getting the car in and out of gear.

And one of them went clean through the inspection cover.

Wow. Thanks for pictures and feedback. I have not heard anything or felt anything unusual, but this may explain how the pressure plate could have uneven release/drag and a high take-up point.

Was the trouble getting in and out of gear intermittent for a while before it came apart?

mphox

I had the same problem with my 02 C5Z. Tried all the "fixes" to get the stock clutch not to stick. Then I installed a Tick master cylinder and this helped for a few days of street driving/testing. As soon as I took the car to the track the clutch was slipping in higher gears. I do not think there is anything wrong with the Tick Master, just was not what I needed to fix my problem. Ultimately I went with a Quarter Master 7.25 triple disc clutch. I also use a Tilton master cylinder similar to the Tick setup but smaller in diameter. I have had no clutch issues since installing the new clutch.

sperkins

Yes. Sometimes you couldn't get it out of gear at all. When you'd start the car, it would start creeping because it was still partially engaged.

UstaB-GS549

Yep that my deal. just need to get thru a weekend at RA and then I can decide if I want to do a clutch job myself or pay the man.

sperkins

"IF" you do have a broken tab, you may be able to fish it out of there with a magnet. Just drop the inspection cover and put someone in the car to press the clutch, start the car etc..(may take a hundred times). It may come loose enough for you to grab it. I know one member that had good luck with this method.

Snidley

I've done RA twice. I had my clutch stick to the floor going into turn 12. I ended up in the pea gravel.

I would not take the chance of my clutch not releasing out there--there are too many high speed straights that don't have a lot of run-off area to drive a car that isn't 100%.

If I was a tech inspector, I wouldn't let the car on the track.

Get it fixed first.

UstaB-GS549

I think I will drop inspection cover tomorrow night and check for broken bits.

I drove it to work today and other than high take-up and more effort, it shifts smoothly.

UstaB-GS549

Well I decided to drive it to RA as I couldn't get the clutch replaced beforehand The entry fee and motel were paid for & non-refundable.

The drive up on Friday was a little bit of a PITA when I hit stop and go traffic jam in Milwaukee. Since shifting was difficult at best, I just left it in 3rd until I cleared the mess. You can slide clutch to get the car rolling from a dead stop in 3rd if you don't care about the soon-to-be-replaced-clutch. Fish fry and drinks at Bo Mallies with friends eased the pain later that evening.

Saturday the drill was to start the car with shifter in 2nd and rev to 4,000 or so for upshifts. Once the car was in 4th, it stayed there for the whole 20 minute session. I was getting a sore arm from pointing people by, but other than that, it was fun as usual.

Something strange happened at the end of the day on Saturday. I was getting tired and without thinking I blipped the throttle, heel and toe downshifted while going into 5. Bingo! I had a normal clutch again... well except for the real high engagement point.

Sunday was really nice as I got to beat on my new AP calipers a bit. I had fresh Ferrodo pads loaded and think I like them. Not a lot of initial bite like the DTC-70's, but really easy to modulate. I was nose to tail with a 911 Carrera for one session on Sunday. He seemed faster, so after 3 laps or so, I pointed him by as he had closed the gap to about 3 car lengths. He came off the corners faster than I could, and slowly he would pull away especially at the end of the long straights. I was able to close the gap in the braking zone any time I wanted to make up the distance. I love my new calipers!

Sunday night in the driveway at home the clutch refused to release again. I thought it had something to do with the car rolling forward and letting the clutch out in reverse with the engine off.

Wednesday the car went in to Chevy and they replaced the flywheel, pressure plate, flywheel bearing, disc, slave and master.

Sperkins: I had one broken tab like those shown in your picture. The rest of the parts seemed to have a lot of life left in them, but with the cost of labor, they got replaced anyway.

I'm not real pleased with Chevy at this point as the new clutch grabs about 1/4" off the floor. They say that it's not adjustable. Technically, it works, but something is wrong just the same. the wife says to take it to the man. He's a pro.... looks like I will be doing it myself afterall...