Last week the clutch pedal felt spongy so i opened up the cap and noticed the fluid was black. I then flushed the clutch system with dot3 until it was clear and within 3 days it was black again but the clutch pedal feels fine. Both the slave cylinder and mater cylinder are only a year old so i have no idea what could be causing the fluid to turn black so quickly.
Is there a special type of fluid needed?

DOT 3/4 brake fluid is the fluid to use. If your fluid is turning black and starting to feel spongy, then you probably have a leak in the line and contaminants are getting in the fluid. Could be the hard line, or the master or slave. You'll have to check for leaks.

your hard line is starting to corrode and rust on the inside .you will soon develop leaks like I did and you will need to replace the line .i got a stainless steel line from the fiero store .it was a PITA to install but my fluid stays clear and no more leaks .i have made new lines out of steel brake line but after a while you will have the same problem again .

quote Originally posted by wftb: your hard line is starting to corrode and rust on the inside .you will soon develop leaks like I did and you will need to replace the line .i got a stainless steel line from the fiero store .it was a PITA to install but my fluid stays clear and no more leaks .i have made new lines out of steel brake line but after a while you will have the same problem again .

Thanks for the suggestion, I have had this problem for a few years and never got an answer before. I do have a new clutch line from the Fiero Store I bought when I was rebuilding the car, just never installed it as I was 'too lazy' - but maybe I should.

Cheers,

The dreaded 'Black Death'. I always thought it was the rubber parts in the system are starting to disintegrate. If you put a magnet into the fluid, you will find there won't be any of the black junk pulled to the magnet. Replacing the parts in the master and slave will also cure the problem.

You could make the line (the bends) from regular brake line, then undercoat the line before installing. Or better yet, powder coat it. Just make sure to cap the ends to keep the threads, seal and inside clean.

They carry some copper nickel line at autozone that doesn't rust and is very easy to bend would be on par with ss but more accessible and for a far price about 25' for $60. If I need to do brake lines that was gonna be my first choice on any car I plan on keeping for a long time. Doing the clutch line with the copper nickel stuff would make life easy since it bends very easy and nicely it'd take alot less than doing a basic steel line and coating it.

Is there no way to clean it out?

quote Originally posted by fierofool: The dreaded 'Black Death'. I always thought it was the rubber parts in the system are starting to disintegrate. If you put a magnet into the fluid, you will find there won't be any of the black junk pulled to the magnet. Replacing the parts in the master and slave will also cure the problem.

I have replaced/rebuilt the master and slave more times than I care to count and that didn't solve the problem - the line is the only thing left.

As for cleaning it out - probably would have to steam it out or something - I have ran a good 4 quarts of new brake fluid through mine to flush the line and it didn't seem to help (so obviously that doesn't clean it).

Is anyone using the newer Dot 5 brake fluid? I read on this forum that it will rot the rubber parts in the clutch and brake system. They recommended staying with the DOT 3.

Dot 5 is not compatible with 3 or 4. Dot 5 is more of a racing brake fluid. It's full synthetic and does not mix well with the other fluids. You need to flush, flush and re-flush if you want to use dot 5. I don't recommend it, because you will not see any benifits unless you race and race hard! No gains for street/daily driving use.