[Z06] Clutch question
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
I tried changing the fluid many, many times. I then did the PITA process of bleeding the system by use of the stock bleeder, which was not fun. The I replced the clutch to an RPS, and new slave. PROBLEM SOLVED!!! Next time I wont waste my time changing fluid and bleeding the system once these syptoms are experienced as you described.
Check back in with us after you've beat on that new clutch a while without changing the clutch fluid. Almost all wind up with pedal issues again once the new hydraulic seals get saturated by clutch dust.
Ranger
Pro
Joined: Jan 2009
Posts: 555
Likes: 15
My clutch fluid never stays clean past a few days, and I have probably gone through 8 bottles of the Prestone DOT-4 following Ranger's methods. Even when the fluid is clean, all it takes is a few WOT pulls to get it sticky and the higher the speed the stickier it becomes.
Team Owner
Joined: Aug 2006
Posts: 30,897
Likes: 45
From: Picking on the weakest kid in the yard.
I was out the other day in the Bro's 2001 Z06 and di a couple of high RPM shifts. The clutch pedal went limp and stuck on the floor.
The fluid in the clutch slave was clean and still is. It's my guess that as time goes on the fingers of the clutch weaken from heat and eventually fail.
Not to say that the clutch slave and hydraulic system have some part in the failure.
Once you get the sticky pedal clutch syndrome, it's pretty much time to pull it all out and figure out what's wrong.
The fluid in the clutch slave was clean and still is. It's my guess that as time goes on the fingers of the clutch weaken from heat and eventually fail.
Not to say that the clutch slave and hydraulic system have some part in the failure.
Once you get the sticky pedal clutch syndrome, it's pretty much time to pull it all out and figure out what's wrong.
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
My clutch fluid never stays clean past a few days, and I have probably gone through 8 bottles of the Prestone DOT-4 following Ranger's methods. Even when the fluid is clean, all it takes is a few WOT pulls to get it sticky and the higher the speed the stickier it becomes.
I suspect you clutch master cylinder has internal leaks from lack of fluid maintenance before you bought it. If that's the case no amount of fresh fluid can heal the seals. That's why it's risky to let clutch dust ever accumulate. It kills the seals.
Anyway, if you answer the Qs, I'll suggest an approach.
Ranger
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
I had this issue. My clutch fluid was perfectly clean yet after just one lap at the track, it was soo bad I couldn't even get the car out of third gear. I thought I needed a new clutch for sure. At Ranger's suggestion, I replaced the master cylinder with a new stock one. After doing so, my fluid began circulating again and all that nasty black fluid that was in my slave and line began returning to the resevoir where I could get it out. My point is, it is possible to have a sticky clutch issue and clear fluid in the resevoir and still not need a new clutch if your master cylinder stops circulating fluid for whatever reason.
The wear surfaces on a properly sized clutch last a very long time. I generally replace mine after 150-175 passes at the drag strip and they are still clamping good as new. What tends to fail is the master cylinder if the clutch fluid is corrupted by accumulated clutch dust.
Good news is the master cylinder is the cheapest element and easily accessed without dropping the drive line.
So if the pedal sticks with pristinely clean clutch fluid on a properly sized clutch, as ptindall stated, change just the master cylinder as a first step.
Ranger
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
Opinions vary.
Lot of shops and dealers prey on owners by urging the replace-everything approach to pedal issues. Owners who follow that approach soon find pedal issues with the new clutch too and their wallets are $1200-2200 lighter.
The conservative approach is always keeping the clutch fluid clean to prevent the hydraulics from failing and keeping the engine torque within the clamping capability of the clutch that's in the car. Do that and you eliminate pedal issues.
Ranger
Lot of shops and dealers prey on owners by urging the replace-everything approach to pedal issues. Owners who follow that approach soon find pedal issues with the new clutch too and their wallets are $1200-2200 lighter.
The conservative approach is always keeping the clutch fluid clean to prevent the hydraulics from failing and keeping the engine torque within the clamping capability of the clutch that's in the car. Do that and you eliminate pedal issues.
Ranger
It's a biotch to get to the bleeder valve on the clutch of C5 or C6.
I tried changing the fluid many, many times. I then did the PITA process of bleeding the system by use of the stock bleeder, which was not fun. The I replced the clutch to an RPS, and new slave. PROBLEM SOLVED!!! Next time I wont waste my time changing fluid and bleeding the system once these syptoms are experienced as you described.
This is the second six speed C5 that me and the Bro have had that has had the sticky clutch pedal syndrome.
When we pulled the first one apart the clutch slave literally fell out in pieces and the clutch was beat beyond belief.
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
Mechanically speaking, the clutch pedal is pushed back up by hydraulic pressure. If you have no leaks in the system, the pressure plate fingers should push back on the throw-out bearing which then pushes the slave back down and thus raise the pedal back up.
My failure only occurs at high RPM shifts when the everything gets heated up, which to me would indicate a faulty pressure plate return action under high rpm conditions.
Once everything cools off the clutch pedal returns to it's normal operation.
My failure only occurs at high RPM shifts when the everything gets heated up, which to me would indicate a faulty pressure plate return action under high rpm conditions.
Once everything cools off the clutch pedal returns to it's normal operation.
I had this issue. My clutch fluid was perfectly clean yet after just one lap at the track, it was soo bad I couldn't even get the car out of third gear. I thought I needed a new clutch for sure. At Ranger's suggestion, I replaced the master cylinder with a new stock one. After doing so, my fluid began circulating again and all that nasty black fluid that was in my slave and line began returning to the resevoir where I could get it out. My point is, it is possible to have a sticky clutch issue and clear fluid in the resevoir and still not need a new clutch if your master cylinder stops circulating fluid for whatever reason.
Great point, ptindal.
The wear surfaces on a properly sized clutch last a very long time. I generally replace mine after 150-175 passes at the drag strip and they are still clamping good as new. What tends to fail is the master cylinder if the clutch fluid is corrupted by accumulated clutch dust.
Good news is the master cylinder is the cheapest element and easily accessed without dropping the drive line.
So if the pedal sticks with pristinely clean clutch fluid on a properly sized clutch, as ptindall stated, change just the master cylinder as a first step.
Ranger
The wear surfaces on a properly sized clutch last a very long time. I generally replace mine after 150-175 passes at the drag strip and they are still clamping good as new. What tends to fail is the master cylinder if the clutch fluid is corrupted by accumulated clutch dust.
Good news is the master cylinder is the cheapest element and easily accessed without dropping the drive line.
So if the pedal sticks with pristinely clean clutch fluid on a properly sized clutch, as ptindall stated, change just the master cylinder as a first step.
Ranger
Team Owner
Joined: Aug 2006
Posts: 30,897
Likes: 45
From: Picking on the weakest kid in the yard.
Mechanically speaking, the clutch pedal is pushed back up by hydraulic pressure. If you have no leaks in the system, the pressure plate fingers should push back on the throw-out bearing which then pushes the slave back down and thus raise the pedal back up.
My failure only occurs at high RPM shifts when the everything gets heated up, which to me would indicate a faulty pressure plate return action under high rpm conditions.
Once everything cools off the clutch pedal returns to it's normal operation.
My failure only occurs at high RPM shifts when the everything gets heated up, which to me would indicate a faulty pressure plate return action under high rpm conditions.
Once everything cools off the clutch pedal returns to it's normal operation.
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Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
Mine too. Around town it was perfectly fine. Only on track would it fail (I don't do high RPM on the street) and as soon as I would pull into the paddock and let in sit for 5 minutes, it went right back to normal. I completely understand your logic. I'm just telling you that I know for a fact you can have horribly fouled black fuid in you slave cylinder causing clutch issues and perfectly clean fluid in you resevoir due to a bad master cylinder because that's precisely what I had with the same exact syptoms you describe.
Thanks for you input.
Le Mans Master
Joined: Jul 2009
Posts: 9,526
Likes: 12
From: Los Angeles California
I just followed the protocol again a few times (about 2 hours ago) and it's shifting even better. I'm still getting a little mushroom cloud of dust when I poor the new stuff in, so tomorrow I'm going to do it... again.
Thread Starter
Drifting
Joined: Jun 2009
Posts: 1,301
Likes: 231
From: Queen Creek AZ
Thanks again Ranger,
Rich
Pro
Joined: Jan 2009
Posts: 555
Likes: 15
No Profile. Is the car stock? If not, power level? Miles on the OD? When you bought the car, was the clutch fluid filthy?
I suspect you clutch master cylinder has internal leaks from lack of fluid maintenance before you bought it. If that's the case no amount of fresh fluid can heal the seals. That's why it's risky to let clutch dust ever accumulate. It kills the seals.
Anyway, if you answer the Qs, I'll suggest an approach.
Ranger
I suspect you clutch master cylinder has internal leaks from lack of fluid maintenance before you bought it. If that's the case no amount of fresh fluid can heal the seals. That's why it's risky to let clutch dust ever accumulate. It kills the seals.
Anyway, if you answer the Qs, I'll suggest an approach.
Ranger
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
My clutch fluid never stays clean past a few days, and I have probably gone through 8 bottles of the Prestone DOT-4 following Ranger's methods. Even when the fluid is clean, all it takes is a few WOT pulls to get it sticky and the higher the speed the stickier it becomes.
No Profile. Is the car stock? If not, power level? Miles on the OD? When you bought the car, was the clutch fluid filthy?
I suspect you clutch master cylinder has internal leaks from lack of fluid maintenance before you bought it. If that's the case no amount of fresh fluid can heal the seals. That's why it's risky to let clutch dust ever accumulate. It kills the seals.
Anyway, if you answer the Qs, I'll suggest an approach.
I suspect you clutch master cylinder has internal leaks from lack of fluid maintenance before you bought it. If that's the case no amount of fresh fluid can heal the seals. That's why it's risky to let clutch dust ever accumulate. It kills the seals.
Anyway, if you answer the Qs, I'll suggest an approach.
If eight bottles of new fluid have not managed to cure the pedal woes on your near-stock powered, 60K Z06, the next step is replacing just the master cylinder. Be sure the part is the most current one for your VIN.
That job requires just removal of the left front wheel and opening the fender liner for access to the master cylinder. A good mechanic can do the swap in less than one hour.
Some owners with access to the shop manual do it themselves.
Once the new MC is installed, I'd suggest 5-10 fluid swaps of the reservoir with driving in between to help disgorge any air that may be introduced during the swap.
Let us know how it goes.
Ranger
Last edited by Ranger; Jul 29, 2009 at 06:48 AM.
Pro
Joined: Jan 2009
Posts: 555
Likes: 15
First off, your Z06 clutch is appropriately size for your power-level. So, excessive slip should not be the cause of pedal issues.
If eight bottles of new fluid have not managed to cure the pedal woes on your near-stock powered, 60K Z06, the next step is replacing just the master cylinder. Be sure the part is the most current one for your VIN.
That job requires just removal of the left front wheel and opening the fender liner for access to the master cylinder. A good mechanic can do the swap in less than one hour.
Some owners with access to the shop manual do it themselves.
Once the new MC is installed, I'd suggest 5-10 fluid swaps of the reservoir with driving in between to help disgorge any air that may be introduced during the swap.
Let us know how it goes.
Ranger
If eight bottles of new fluid have not managed to cure the pedal woes on your near-stock powered, 60K Z06, the next step is replacing just the master cylinder. Be sure the part is the most current one for your VIN.
That job requires just removal of the left front wheel and opening the fender liner for access to the master cylinder. A good mechanic can do the swap in less than one hour.
Some owners with access to the shop manual do it themselves.
Once the new MC is installed, I'd suggest 5-10 fluid swaps of the reservoir with driving in between to help disgorge any air that may be introduced during the swap.
Let us know how it goes.
Ranger
Can you show me the right part and where to get it?
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
Suggest calling several of the forum sponsoring dealer parts depts and giving them your year/model/VIN. They should give you the latest part number for the clutch master cylinder.
You can order the part from them or order it from one of the online GM parts suppliers.
Ranger
You can order the part from them or order it from one of the online GM parts suppliers.
Ranger
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 31
From: Central Florida
