badams1897

So I know the clutch to the floor issue has been beat to death, however I have a unique one I think. I just bought my z06 with 48k miles on it. Drove it all the way from Florida no problem. The clutch did feel a little mushy, and I noticed some slight sticking. I checked the fluid and it was indeed black as night. So I did the ranger method with Prestone Dot4 Synthetic fluid. Got it all cycled through and drove it the next day. Clutch seemed to be actually improved and more responsive, with a firmer grab. Car got hot, clutch went to floor and stayed there. The fluid was also black as night again this is after I cycled an entire bottle of Dot4 through.

I took it to the dealer (after limping there) and by luck and google and this forum I found it has a 10 yr 100k mile warranty on the master clutch cylinder. I asked them about it, they looked up the bulletin and indeed replaced it under warranty. I spoke to a very knowledgeable service mechanic who specializes in corvettes and even races one and asked about the ranger method. He said that is the best way to cycle clean fluid into the system. I followed the ranger steps to the letter (watched the video 100x and read the entire ranger site over and over). Has this ever happened to anyone else? I find it crazy I drove 1500 miles on it fine, ranger method and boom master clutch cyl bye bye.

The car did sit idle running in an audio visual shop in AC for 20+ min. Oil and water stayed normal, but could the clutch fluid gotten too hot? How on earth did it turn black again? I don't fully understand but investigating.

SocalChvy

I think the Ranger method is a great way to maintain your clutch fluid but it's only effective if your fluid hasn't degraded to a point to where you've impacted your slave/master cylinders.

To take it the next level, instal a remote bleeder next time you do a clutch swap. I loved my old fluid reservoir. It was transparent so I could look at the fluid and tell if it needed to be flushed. Now I have to newer darker one that requires DOT4 fluid.

Dan_the_C5_Man

I don't have all the answers, but one thing I might help clarify for you - the fluid is not turning dark / black due to heat - it's due to the seal materials in use. I will also say that lots of people don't mess with the stock fluid at all, and don't have these issues.

The sticking to the floor is usually due to heat loading in the slave area (most people have this issue on hard pulls with headers). Not sure if you know this, but the stock slave has a plastic (yes, plastic) bushing that some people replace with a billet peice. There are other design flaws with the slave that contribute to these issues.

I've never bought into the whole "so long as you keep your fluid pristine you'll never have any issues" argument , as there is plenty of evidence to suggest the discolloration from the seals can be relatively harmless.

JimsCorvettes

In my 2006, I did the ranger method I would say 40 times before the fluid would actually stay clear. Bought the car with 41,000 miles on it and I am sure it had the original clutch fluid.

badams1897

I agree its not heat, its obviously clutch material getting into the fluid. I am just wondering if the heat from idling led to the failure.

fasttoney

I just pick my Zr1 up from the dealer today. After getting my master cylinder replaced under warranty. The car has 27k miles and I just purchased the car. I put 50 miles in it before it fell to the floor on the first day of driving it after purchase. The previous owner gave me receipts where he had recently changed the fluid. On my first drive I made a few stops and leaving the car running at each stop( showing family new purchase). My last stop, I was showing a friend of mine. He was looking at the car while it was running. I opened the mild to wild switch. Gave it a couple of revs. After about 10 minutes at idle. I was now leaving. Je told me to get on it. As soon, as I pushed the clutch pedal in. Ot went to the floor. The car has headers. And I believe all the idling, and heat soak contributed to the seals in the master cylinder failing. This is my story.

OP, didn't mean to jump on your post. Just want to share my story.

Dan_the_C5_Man

I don't know that it is indeed clutch material. Thinking about it, I wonder if one could send a sample to Blackstone labs, have them do a spectrum analysis on it, that might answer this long-standing question.

badams1897

I thought Ranger did have his fluid sent to a lab and it was clutch material in the fluid?

Also what is with the new black clutch fluid reservoir? I guess have to use a Q-TIP and see if the fluid is dark... Fail GM.. Fail.

On the plus side drove the car for about 6 hours today on a trip, a few hard pulls and some light traffic seemed ok...

HT1663WB

I had the same issue. I bought my 08 Z06 in June with 25k on it. First thing I did was change the clutch fluid using the Ranger method. A few days later, while putting on a new clutch pedal spring, the clutch dropped to the floor. A forum member told me about the special warranty on the clutch master cylinder. I called my local dealer and it was covered. I was told the tow would be on me. Since the tow would be over $250 and the part was only $140.00 I just did it myself. I'm glad I did because that new rubber gromet that goes in the firewall was a son of a bitch! I had the dealer add a bottle of GM brake fluid when I picked up the part. They gave me DOT3. Fluid has been clear since changing the clutch master.

Apocolipse

The dark fluid is 100% from clutch material.

fasttoney

I thought they use dot 4?

badams1897

It uses Dot4.. My new one with the black fluid container has DOT4 in BIG BOLD BRIGHT WHITE letters. Use DOT4 for clutch. Confirmed with GM specs.

HT1663WB

Yes, mine says the same. I used dot 4. It was funny to me that they gave me dot 3. Dealer said that is what they used.

fasttoney

That's why I asked. Just picked mine up on Friday from having the master done.

Les-10

Did you notice any difference in pedal stiffness? easier or more difficult to depress/di
sengage?

Frankie15

Do you guys thinks it's worth replacing the clutch master cylinder with the new part as preventitive maintenance? I'd hate to be stuck on the side of the road with the stuck clutch pedal. I've been doing the ranger method every few months since I bought my 08 Z exactly one year ago. The fluid is never black, but I always change it anyways.

Dan_the_C5_Man

I'll have to do a search on that one.

fasttoney

its funny you asked. Because my pedal felt stiffer. But in a good way. But, I noticed today they didn't reconnect my spring. So I reconnected the spring. And it was alot less stiff.

fasttoney

You can drive it with some finess, if it goes to the floor. But, I dont think it would be a bad idea to change it for prevention. Especially, if you can do it yourself. Or it wont cost you an arm and a leg. I think the upgraded master is about 100 dollars.

HT1663WB

I would, mine went to the floor and it wasn't even running. I was replacing the clutch spring. It's a fairly easy part to replace it's just getting the new grommet seated in the firewall and connecting the new line. You can really only work with one hand. The new clutch master comes pre-bleed and full of fluid. The new master from GM was $146.00. There was no way to drive the vette when mine went out. The clutch pedal acted as if it was disconnected. Good luck, Bill