Bad clutch omen?
Thread Starter
Racer
Joined: Feb 2005
Posts: 332
Likes: 21
From: Georgia
Bad clutch omen?
Wondering if my stock clutch is on it's way out. I have on a mildly modded '02 C5, headers, etc, with 30k miles. While I don't baby the car and I routinely hammer it and, shall we say, use it to its reasonably full potential without ending up in jail, I don't typically do hard launches from a stop while slipping the clutch at higher RPM's. I'm more of a roll on, shift near redline, rip through some gears driver. Easier on the clutch, etc. Well, ONE hard launch tonight from a light, as one might do at the drag strip, and the clutch immediately went to mush, briefly stuck on the floor, causing me to miss second.
So, in short, what's going on here and does this sound like a new clutch is in the near future? I could understand the stock clutch behaving like that after the heat of repeated launches, but one hard launch and the thing rolls over and plays dead? I have plans this fall of doing an HPDE and hope that the stuck clutch is up to the task. Tonight's behavior worries me.....
So, in short, what's going on here and does this sound like a new clutch is in the near future? I could understand the stock clutch behaving like that after the heat of repeated launches, but one hard launch and the thing rolls over and plays dead? I have plans this fall of doing an HPDE and hope that the stuck clutch is up to the task. Tonight's behavior worries me.....
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2020 Corvette of the Year Finalist (performance mods)
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it's more than likely either the hydraulics or the pressure plate, both suck to be honest... you can try a full fluid bleed and that might help then a tick master cylinder would be my next route... if that doesn't work replace the clutch with something other than the stock unit, replace the slave at the same time, and add a remote bleeder... I had to do all of the above to get mine to shift properly, kinda sucks having to spend so much just to be able to run through the gears at wot... normal driving was never an issue, only the high rpms gave me problems before I changed everything out
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I have an 02 Z. I modded it to 390 RWHP and didnt have any clutch issues.
Did a head, cam, fast 90, install which brought it up to the 450 mark. Immediate clutch to the floor under full power shifts.
When I changed the clutch, the disk, pressure plate and throw out bearing and the disk really didnt look that bad. The disk wasnt worn much at all.
Here is what I found that I believe was the issue. The hydraulic system failed under stress. I disassembled the old master cylinder and it was packed full of clutch dust slime. I believe that was the cause of my clutch issue.
If I had to do it all over again, I wold have flushed the entire clutch hyd system and if that still didnt fix it, I would change the clutch master cyl next.
I installed a SPEC Dual disk clutch and went with the TICK Master.
Did a head, cam, fast 90, install which brought it up to the 450 mark. Immediate clutch to the floor under full power shifts.
When I changed the clutch, the disk, pressure plate and throw out bearing and the disk really didnt look that bad. The disk wasnt worn much at all.
Here is what I found that I believe was the issue. The hydraulic system failed under stress. I disassembled the old master cylinder and it was packed full of clutch dust slime. I believe that was the cause of my clutch issue.
If I had to do it all over again, I wold have flushed the entire clutch hyd system and if that still didnt fix it, I would change the clutch master cyl next.
I installed a SPEC Dual disk clutch and went with the TICK Master.
Thread Starter
Racer
Joined: Feb 2005
Posts: 332
Likes: 21
From: Georgia
Thanks for the reply. I'm thinking I'll be traveling the same road you've been down, master cylinder, new aftermarket clutch. What I still can't understand is how a single, hard launch could create enough heat to stick the pedal to the floor. Is it boiling the fluid in the slave cylinder? Pressure plate sticking? Still not sure what's going on mechanically to cause it to happen so quickly. I know the cure, you might say, I just don't understand the disease.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I didn't understand it either and If I would have followed my own advice (hind sight 20/20) I may had had an answer for you.
If you refresh and bleed the fluid, replace the master Cyl and it still does it,, you know its the slave or pressure plate.
Some speculate that the pressure plate over centers and stays disengaged but, I can not verify that theory.
Bill
If you refresh and bleed the fluid, replace the master Cyl and it still does it,, you know its the slave or pressure plate.
Some speculate that the pressure plate over centers and stays disengaged but, I can not verify that theory.
Bill
Race Director
Joined: Jan 2008
Posts: 16,028
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From: oregon
like bill said, no one is really 100% on what causes this but we have a few suspects
if bleeding doesn't cure it you can get an ls7 clutch with an aluminum ram flywheel from scoggin dickey under 600. this clutch drives just like what you have but won't fail under pressure on a bolt on car
if bleeding doesn't cure it you can get an ls7 clutch with an aluminum ram flywheel from scoggin dickey under 600. this clutch drives just like what you have but won't fail under pressure on a bolt on car
Thread Starter
Racer
Joined: Feb 2005
Posts: 332
Likes: 21
From: Georgia
Yup, it drives just fine, the only complaint like this from the clutch was that one hard launch. What worries me are my plans to do a track day event in September and having to contend with a clutch that won't cooperate. Trying to figure out how dissimilar a road course is from one very hard launch as far as the clutch goes. Gamble or bite the bullet and go with an aftermarket clutch before the track day?
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Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
Yup, it drives just fine, the only complaint like this from the clutch was that one hard launch. What worries me are my plans to do a track day event in September and having to contend with a clutch that won't cooperate. Trying to figure out how dissimilar a road course is from one very hard launch as far as the clutch goes. Gamble or bite the bullet and go with an aftermarket clutch before the track day?
see what you get, may fix your situation
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
Yup, it drives just fine, the only complaint like this from the clutch was that one hard launch. What worries me are my plans to do a track day event in September and having to contend with a clutch that won't cooperate. Trying to figure out how dissimilar a road course is from one very hard launch as far as the clutch goes. Gamble or bite the bullet and go with an aftermarket clutch before the track day?
Platinum Supporting Dealership
Joined: Jul 2014
Posts: 722
Likes: 336
From: Rochester New York
Could be the pressure plate, could be the hydraulics (slave, master). My bet is on the pressure plate if it was a hard launch and it stuck when shifting into 2nd. I had a customer experience this issue, pressure plate would stick and wouldn't self adjust properly.
If you choose to put a new clutch in, do your self a favor and install a new slave & new master & remote bleeder!
If you choose to put a new clutch in, do your self a favor and install a new slave & new master & remote bleeder!
Thread Starter
Racer
Joined: Feb 2005
Posts: 332
Likes: 21
From: Georgia
Could be the pressure plate, could be the hydraulics (slave, master). My bet is on the pressure plate if it was a hard launch and it stuck when shifting into 2nd. I had a customer experience this issue, pressure plate would stick and wouldn't self adjust properly.
If you choose to put a new clutch in, do your self a favor and install a new slave & new master & remote bleeder!
If you choose to put a new clutch in, do your self a favor and install a new slave & new master & remote bleeder!
Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
Yes, that seems to make the most sense to me too. I couldn't believe that one hard launch would be enough to heat up the fluid in the slave enough to boil it and lose pressure. The pressure plate, however, would heat up very quickly under a hard launch and would be first to fail, I would think, before the slave. Repeated hard launches, where lots of heat is generated? Sure, I would think it would be possible to boil the fluid in the slave under those conditions. Also, considering my fluid was reasonably fresh after numerous "ranger" method "bleeds" quite recently, my bet is further on the pressure plate too. Now, still, the question is will it likely act up during a road course HPDE………
clutch sticking to the floor on a hard launch is common
ranger method seems to take aprox 2000-3000 miles with bi-weekly flushes to see if it works. did this to my car after i bought it, had a similar problem, works mostly fine now unless i really am on it for awhile. a simple drag race is no problem though.
make sure you understand the balance issue before you replace your clutch
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
I had the clutch sticking to the floor syndrome on my stock 03 Z. I replaced the master and slave cylinders (with OEM parts 50k miles ago). I now change my clutch fluid annually and have not had the problem recur. Sludge in the system is your enemy.
Last edited by 3sACROWD; Aug 7, 2014 at 09:03 AM.
Burning Brakes
Joined: Feb 2013
Posts: 749
Likes: 13
From: SoCal CA
Here's a site with some good information. Look in the "clutch care" section.
http://www.rangeracceleration.com/
http://www.rangeracceleration.com/
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
There was a performance shop that posted a few times about multiple customer cars with added HP not having clutch issues after removing the plastic fill-in covers on each side of the bellhousing. I would try bleeding the clutch completely and removing those covers and see where you stand.
Thread Starter
Racer
Joined: Feb 2005
Posts: 332
Likes: 21
From: Georgia
Thanks for all the helpful info guys. I'm also looking into the Lingenfelter clutch spring kit that essentially forces the pedal back with the addition of a supplemental spring. Still having difficulty visualizing how the clutch pedal would pull the pressure plate back. Forgive me mechanical ignorance of the finer mechanisms of the clutch, but is that physically possible for the clutch to "pull" the pressure plate back after it sticks or is it a one way system where the pressure plate can only "push" the clutch back "up"? It would seem to me that a hydraulic sticking via slave/master cylinder could be cured by a stronger "return" spring in clutch, but not a pressure plate sticking unless it's physically able to be "pulled" back into place.