Clutch won't disengage. 2003 g35 6mt
 

I have a vortech setup and i switched to a comp clutch stage 4 (6 puck sprung). I also installed forged performance stainless line. We had a hell of a time bleeding it but it has been working good for a few weeks.

Last night at the drag strip I did a 4500 rpm launch and when i pressed the clutch in to shift to second gear it wouldn't come out of first. After pulling off the track i noticed that the car drives fine but the clutch pedal doesn't do anything. There is pressure just like normal, but it doesn't disengage when you push on it. With the car off it shifts through all gears.

We have it up on jacks now and the slave cylinder does push the clutch arm when the clutch is pressed but only about 1/2". Shouldn't it push it further? There are no noises or anything with the trans.

I'm thinking 3 things: air bubble which compresses when you push the clutch, slave cylinder or master cylinder.

If the slave cylinder goes out will it still move teh clutch arm at all? It just seems like it's not moving enough now. There are no fluids leaking at all.

The next question, since i have a heavier clutch, is there anything that will upgrade this slave cylinder so it doesn't break again if that happens to be the problem?

Thanks!

If there was air in the system the pedal should stick to the floor.... It could also be a bent arm that is alot more pressure than it was meant to handle. Another thought the pucks may have slipped/stacked not giving enough clearance when clutch is pressed. (hopefully not because that would mean probable damage to input shaft) Post what you find this has me curious.

Ok, bad news:

I replaced all the hydraulics with new ones. The clutch arm is still only traveling the same distance as before when the clutch is depressed. We bled the crap out of it also and no more bubbles were coming out.

It has to be something on the clutch side then not alloing the arm to disengage the clutch. Monday we are getting the car hauler and going over to pick it up to get it back to the shop. More than likely i'll have the trans out monday night because i'm confused and want to know wtf is going on really bad.

The clutch is only a month old and has just over 500 miles. Drove it for 2 weeks to get 500 miles and break it in then i've been actually using it for the last 2 weeks. Only 2 "real" uses on it though where i actually tried to launch hard. I'm not dumping the clutch or abusing it either.

As for input shaft damage: i don't think that is the case or the car wouldn't drive fine in first gear. I can start the car while it's in gear and it takes off but i'm stuck in whatever gear i have it in. it drives without noise or problems like that.

Yeah i figured it was probably not hydraulic related, I haven't looked at it but would guarantee there definitely is a clutch disc clearance issue, or a problem with the fork inside the tranny.

the clutch fork or a shift fork? it's all the gears so it's definitely an engagement problem and the clutch not freeing up. This is a new cd009 trans so I doubt i killed it with a lame 2.0 second 60' launch...lol

It'll be in the shop tomorrow afternoon and i'll tear it apart as fast as i can. I'm so lost at what could have gone wrong that i can barely wait to see. Maybe a spring came out, bolt sheared off, clutch disk fail. I've seen a few things online that the puck clutch friction plate broke and jammed into the pressure plate causing it to be stuck.

The clutch release fork was the one i was talking about. Not a problem you would normally see but on some centrifugal style clutches clamping force is so high at 6,000 rpms that strange things can happen lol what brand clutch/flywheel is it?

competition clutch stage 4, 6 puck sprung

My best friend from growing up is a master tech at a bmw/infiniti dealership. It's sitting at his house and he's stumped also.

I doubt after 2 passes it got hot enough to melt the friction plate to the flywheel but i guess stranger things have happened. It never slipped a single bit so i don't imagine it would get slip and heat up enough to do that.

Maybe a bent pressure plate not allowing the clutch to engage?

it's not DISengaging. So the transmission input shaft is basically always spinning when the motor is on.

I can't get the trailer today because my buddy is working on his new house. He'll be free tomorrow to help me get the car.

Ok, i pulled it apart last night.

The friction plate was welded to the flywheel and pressure plate. There are missing pieces of the pucks also.

here are a few pics. Hard to see but the black dots on the flywheel and pressure plates are friction material stuck into the metal.

That is the first time I have ever seen or heard of that happening. But I see something new everyday. lol That is crazy have you talked to the clutch/flywheel mfg about possible warranty I know it's a performance part but that shouldn't happen. Those pucks are made out of mostly organic material and shouldn't do that. It's at least worth a shot.

clutch is at comp clutch now being inspected.

I purchased an OS Giken twin disk for the car and it has been in the car for almost a month now. Works great!

comp clutch called me yesterday about the warranty but i was at work and couldn't take the call. Maybe i'll get ahold of them monday and see what's going on.

WOW!! first time for everything...I was thinking maybe throw out bearing but if so you wouldn't be able to get into gear. I hope they refund you for the clutch or send you a new one...

throw out bearing is perfectly fine.

we found what the problem was with my car. The clutch plate and flywheel were welded together. Now the question is WHY. Hopefully when i talk to CC on monday they will havea better explanation after looking at the clutch. It was far from being abused and with my probably not even 400hp car it wasn't over powered.

we shall see what the verdict is:thumbup:

yea...Looks like you had that one rare off occurrence of strangeness...

fingers crossed for you...

ya, that's the story of my life....lol

i'm crossing my fingers hopefully to get a replacement. I have a twin disk os giken in there now but it still sucks i'm out 600$ for a clutch.

If they do send a replacement for the clutch list it on ebay and it will help soften the blow of having to buy another clutch :D Good luck with the new twin disk clutch, hopefully it holds up well!

I was either going to do that or sell it to my friend here locally for his 350z.

twin disk is operating beautifully!

ok, i just spoke with Dan from Competition Clutch today.

I won't have the failure analysis report until tomorrow since he went home early sick. This is what he told me on the phone.

The clutch mic'ed out just fine and there was no indication of the pressure plate or friction plate that there was a manufacturing defect. The friction plate is in good condition with no damage to the friction surfaces. The pressure plate has good tension and in good working order. The face of it was not damaged and is true. He said giving it a light buff with some sandpaper before re-installing it would be sufficient for use.

The issues with it sticking. He said that it's usually caused by grease fling or improperly adjusted clutch pedal causing a slip and then excessive heat. He found no evidence of grease therefore he thinks it was improper clutch pedal adjustment allowing the throwout bearing to ride on the pressure plate and slightly slipping the clutch. When it overheated it stuck together.

I thought I had my clutch adjusted properly and it worked great on the street. Something must have changed at the track. Maybe heat on the clutch line caused it to fatigue and not give me the pressure i needed? That would be my only explanation.

So all in all this clutch is in good working order and he said it should give me years of use left. Again he advised at the most he would do a light sand to scuff up the pressure plate surface before re-installing. Installing without doing that should be fine but it wouldn't hurt to scuff it up and do another light breakin.

I guess i'll have to be more careful with my clutch adjustment. I switched to motul for brake fluid and it's properly bled and the clutch pedal is adjusted. Hopefully i don't have this issue again.

if your clutch peddle was improperly adjusted then your new clutch would suffer the same fate. an improperly adjusted clutch peddle to cause that would have to have a grap point so low that basically the clutch does not properly dis engage. If so you new clutch would exhibit the same symptons plus a setup with an error such as that will display its errors early before failure.

If there was greese involved plus high temp heat, I would think he should have found traces of greese (which he might have) but most greese used in MT applications can tolerate high temps of heat.

Did you bleed and adjust the clutch before you installed the current clutch that is in the car now? If not then theoretically I would think the same issue would have manifested itself.