Mine goes black fairly quickly. I just assume it's the seals breaking down in the master and slave but I've also heard from some corvette guys that valvoline fluid sucks for clutches and promotes the dirty fluid situation. They also seemed to indicate that the black stuff is clutch dust entering the closed system. Something about the o ring sweeping it in on the return stroke. I'm not convinced but not closed minded.

I fought with my clutch hydraulics today for hours today, I've just got clutch stuff on the brain.

If your talking about the fluid resivoir, I flushed it recently. It has stayed crystal clear ever since. It was a bit brown/black at the bottom, I flushed a good amount of nasty out of the lines.

i need to flush mine soon, its kind of dirty/brown.

Boostinsideways said:

If your talking about the fluid resivoir, I flushed it recently. It has stayed crystal clear ever since. It was a bit brown/black at the bottom, I flushed a good amount of nasty out of the lines.

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How many miles will it stay clear for?

I've put about 500 miles on the car before I found fuel leaking from piston 1 fuel injector @ the lower seal. So I pulled the rail to inspect and launched the bugger into the air and never saw it again. Waiting on new seals in the mail.

I flushed it with an entire can of brake fluid though. I doubt it will go dark for few months at least. I also have new oem slave and master cylinders. Will be doing a SS clutch line when I get due for another fluid flush and fill.

Mine always come out clean. Then again, I do change my fluid when I change my engine oil since it tends to get thin fairly quickly (pennzoil synchromesh).


Edit: Just realize this is the clutch fluid poll not tranny fluid.. I have a new master/slave+ braided line. Last time I bled it, it was clean.

A lot like brake fluid! Just messin stays pretty clean.

Those who don't experience any sooty black build up in their reservoir, what fluid are you using?

Where is the "other" option, my fluid is blue . I suppose clean since I just flushed it recently.

LiQUiDx said:

Where is the "other" option, my fluid is blue . I suppose clean since I just flushed it recently.

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What fluid is blue? I've only bothered to use items such as Prestone, Valvoline and the like.

ATE Super Blue race fluid. I use it for both brakes and clutch.

LiQUiDx said:

Where is the "other" option, my fluid is blue . I suppose clean since I just flushed it recently.

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Same Here

PieEyedPiper said:

I've also heard from some corvette guys that valvoline fluid sucks for clutches and promotes the dirty fluid situation. They also seemed to indicate that the black stuff is clutch dust entering the closed system. Something about the o ring sweeping it in on the return stroke.

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I've used Valvoline fluid before without any issues. I use ATE Super Blue now. And they even have a clear Super Blue so you alternate between flushes so you know all old fluid has been removed.

And if dust is entering the system you have major problems! It would have to get out of your bell housing, enter your slaves dust boot, and then bypass the internal seals... Not happening.

The Corvette's slave rod enters the bell housing, so their story may be more likely, but still not very believeable.


If I had to bet, I would say it's the rubber dust cap or whatever it's called that sits in your reservoir cap breaking down. Also a known issue to cause Corvette's black clutch fluid.

You may want to check the rubber hose on the reservoir, mine is staring to deteriorate and may be causing it.

Mine is always clear. Change it when it gets dark. If it darks within a month. Change out the Master

housegsx said:

It would have to get out of your bell housing, enter your slaves dust boot, and then bypass the internal seals... Not happening.

The Corvette's slave rod enters the bell housing, so their story may be more likely, but still not very believeable.


If I had to bet, I would say it's the rubber dust cap or whatever it's called that sits in your reservoir cap breaking down. Also a known issue to cause Corvette's black clutch fluid.

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Read my mind!

red_devil said:

You may want to check the rubber hose on the reservoir, mine is staring to deteriorate and may be causing it.

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Good one, will do. I'm rebuilding my master tomorrow since I have the worst case of 2g ghost pedal I've ever seen. I had no idea it could possibly be so bad. I bet even a bottlebrush/pipecleaner type treatment to that hose would remove/clean it up a lot.

When you guys are "flushing" your fluid (way cool on the blue vs clear btw) how many are just doing the old turkey baster method vs. full on bleeding?

Corvette mantra:
http://forums.corvetteforum.com/1555670709-post32.html