ODEN2

If this is a dupe, I apologize, but I am search function challenged where this forum is concerned.

When I raised the hood of my new Z06, I saw, in typical GM fashion, the solution to the "black clutch fluid problem." It was simplicity in action... a BLACK CLUTCH FLUID RESERVOIR! Out of sight, out of mind.

I think I'll continue to replace mine as usual for the time being.

What say you experts?

charles

Gary '09 C6

really...what a joke.

...GM, tell me again how much better-quality seals would cost ?

glass slipper

The problem isn't the color of the fluid or poor quality seals, it's a design problem with the clutch slave cylinder or more to the point where the slave cylinder is located. When excessive slippage occurs like during racing, heat builds up and gets concentrated in the slave cylinder to the point the clutch fluid boils. Air bubbles don't compress which causes the clutch pedal to go to the floor and the air bubbles take a little time to come out of solution so you have to wait. Once it cools down and the air bubbles are gone, the clutch starts working again. Changing the clutch fluid often keeps the boiling point high, the dark fluid is just an indication of how long the fluid has been in the system. If you go to a much higher boiling point fluid and/or provide free/forced ventilation, you can greatly reduce/eliminate the stuck clutch pedal problem.

JerriVette

Gm recommends changing the clutch fluid once every year or two. Do not do the ranger method. I pay the dealership I believe under 100 dollars every second oil change. My c6 with this protocol never in 88 k miles ever had a clutch problem.

Changing or opening up the clutch fluid reservoir to do the ranger method is not recommended by my gm world class tech.

My c5 z06 was a nightmare with sticking clutch pedal.

The color is not something to worry about. Just have the clutch fluid serviced as I described. You'll have no issue.

Jmo

b4i4getit

JerriVette is absolutely right. Don't waste your time doing the reservoir fluid change. It might make you feel good to have clear fluid in the reservoir but it will have no effect on the fluid in the slave. If you are doing a lot of high rpm shifts and boiling the fluid you should change it every year. However if this is just your weekend toy you probably could go many years without changing the fluid. I believe one guy on the forum named Bill Dearborn went many years without fluid change and never had a problem.

Larry Bittner

I had the problem of the pedal sticking to the floor on my C6. After fooling around with the turkey baster I discover the Tick Performance Master. Since changing it our a couple of years ago the pedal never sticks to the floor and the fluid remains clear.

SBC_and_a_stick

I checked my brake fluid and it is indeed black in a black container.

TEXHAWK0

Unless GM changed the design, the problem is not overheating the clutch fluid.. A forum member tested the fluid and found that it was dark due to clutch dust getting by the seals. I think there is also a correlation on how much clutch dust is generated by high RPM shifts and how fast the fluid turns dark.. I changed the fluid on my C5Z06 every 6 months or so, and it never did turn dark.

quick04Z06

How do you change the fluid? The clutch is very hard to access, as I understand it.

glass slipper

Please describe in detail the mechanism by which the clutch dust mixed with the clutch fluid causes the clutch pedal to stick to the floor?

JoesC5

I change out the clutch fluid in my C6 Z06 every 6 months. I use the Ranger method, and at 39,000 miles and seven years, I've never had a sticking clutch. Takes one bottle of fluid(less than $4) and around 15-20 minutes( I don't get paid by the hour).

I change out the black fluid in the reservoir with fresh fluid, put the cap back on, and then (without starting the engine) push the clutch pedal 15 times. Then I change out the fluid again(and the fluid is nearly as black as it as before I started), cycle the clutch pedal 15 times, and repeat. I do this 5-6 times to use up most of the bottle of brake fluid).

Each time I change the fluid and cycle the clutch pedal 15 times it is lighter than the time before, and by the time I do the last change over the fluid is as clear after the 15 clutch pedal pushes as it was before the 15 clutch pedal pushes. That tells me that the new fluid has mixed with the fluid in the slave cylinder and by the time I get through, both the fluid in the reservoir and the fluid in the slave cylinder is clear, and clean.

If the fluid wasn't mixing, the first time I changed the fluid with clear fluid it would still be clear after cycling the clutch pedal 15 times, as I never started the engine, thus did not generate any additional clutch dust. Each time I refreshed the reservoir with clear fluid, it got dirty(but less dirty) after cycling the clutch pedal 15 times and after 5-6 reservoir refills, the fluid was clear after the last 15 clutch cycles.

I do keep the cap on the fresh bottle closed(except for when I'm pulling fluid out of it) and I keep the cap on the reservoir except for when I'm removing the dirty fluid and adding the fresh fluid. After I'm done, any fluid(very little) remaining in the new bottle, is discarded. I always start with a new sealed bottle.

stevebz06

My Camaro has the same design, doesn't get driven hard very often at all anymore and had the same issues as my Corvette. I put in a remote bleeder on my Vette when I needed a new clutch and I would recommend that to everybody. You need to be a contortionist to bleed the clutch, otherwise.

As far as the turkey baster technique goes, there is an exchange of fluid from the slave to the master reservoir, so I think it's worthwhile to do. Taking the cap off will allow humidity to come into contact with the fluid, but if you are replacing the majority of that fluid with new,
I would think that the total moisture content would decrease. I used to do it weekly while I was running the car hard in competition. It just takes a few minutes. Using the remote bleeder actually takes longer, but you're more sure of getting most of the old fluid out.

Putting heat insulation on the tubing that runs from the master to the slave, also seemed to help, which makes me believe that at least part of the problem is simply related to heat.

Reciprocal

I wonder if anyone advising against the ranger method has any first hand experience with clutch problems from doing it? When you consider the fluid volume is low to start with, it is probably a lot more efficient at purging out the old fluid which gets vacuumed out of the reservoir and replaced, than you might think. I dunno, I've been doing it with every oil change for almost 5 years on my ZR1 and no hint of clutch problems, so far. When that fluid starts coming out clear, I think it's fairly well replaced, since it's been repeated for 5x the amount of fluid in the reservoir when I'm finished.

TEXHAWK0

The clutch slave cylinder is in the same housing as the clutch, and dust can enter the system on that end.
To bleed the whole clutch system you do have to get to the bleeder valve which is up inside the tunnel and hard to reach.. Replacing fluid in the reservoir just dilutes the dirty fluid until most of the particulates have been removed.

JoesC5

A friend(in his eighties) with a 2009 ZR1, and he very seldom drives it, and has very few miles on it, went out to his garage and started the car(it had not been started in months so it was cold, as was the clutch fluid). He pushed the clutch pedal to the floor to start the car, and when he went to back the car out of the garage, the pedal was stuck to the floor. He has never shifted the car at high RPM's, had it on a track, etc: just easy street driven, and he had never removed the cap off the reservoir allowing moisture to possibly enter the system.

He had to call a roll back, had it trucked 60 miles to Reliable Chevrolet, and they flushed the system out. It ended up costing him over a thousand bucks. He wasn't aware that there was a problem with sticking clutch pedals(before that incident) and it cost him a lot more than what it cost me to flush my system out at $4 every six months.

AZDoug

GM solved this problem last year.

The fix is called 8L90.

Doug

JoesC5

And you will be paying an additional $3,025($1725 + $1,300 GGT) for the privilege of not having to flush your clutch fluid every six months at $8 annually yourself, or to have a dealer do it every two years at a much higher price. Does every manufacturer of cars with manual transmissions require that you flush the system every two years or does GM only have the problem with sticking clutches?

Lets see, 378 years later, and we're even($3,025/$8 = 378).

AZDoug

Even for 2016? Do we know the manual trans car isn't a GG for next year?

I would pay the tax anyway, as shifting generally sucks compared to a good auto trans, though I don't have any experience with the manual trans in this particular car. I have few stick sports cars already, which are fine on the highway, but tiresome in traffic..

Doug

b4i4getit

This was discussed years ago. For the benefit of any new forum members read the last thread in this post before you waste your time.

https://www.corvetteforum.com/forums...er-method.html

JoesC5

GM isn't going to do anything to the Z06 for 2016 that will lower the gas mileage, thus there will be no GGT on the 2016 manual transmission Z06, and I have heard nothing about the .gov raising the 22.5 MPG limit where the manual transmission would end up paying the GGT. Even if the .gov did that, it would also raise the GGT to a higher amount on the auto transmission Z06.

Unless you have a bad left leg, or spend most of your time sitting at traffic lights, the Tremec manual transmission is an easy transmission to drive, and the Corvette's clutch pedal takes very little force to depress it.