I did a lot of work with my clutch hydraulics last summer, and I remember finding all the clutch fluid just BLACK when I bled the system. It's black again, though my clutch works fine.

Does this happen to you? Is it a problem?

 

The black is contamination in the fluid. Could be water, rubber, etc.

Define "did a lot of work with my clutch hydraulics last summer"? If you didn't replace the the
line, slave cylinder and master cylinder the older components may be causing this from age.
I've always replaced all 3 together.

 

the clutch fluid gets dark quick, but it doesn't really seem to be a problem. its also really easy to change.

 

Every 1st gen I've owened has had clutch hydraulic problems. If you look at the angle of the slave cylinder and the clutch fork, it's obvious that the rod the goes from the piston to the fork is at an odd angle. This causes the slave piston to wear at an odd angle. The worst I saw was when the slave died on a trip and when I pull the slave and took it apart, the piston was ground down to a 45 degree angle; I'm surprised it worked that long. I had a spare kit I always carry and got back on the road in five minutes.

When I went through all the systems. I bought a new master and slave parts along with an SS line and I also use silicone fluid. A year or so later I had to remove the tranny and I compressed the slave all the way in and used a wire tie to hold it in place. Well, this destroyed the seal for some reason so I replaced it and the piston and bore on the slave looked new after a year of work.

My advice, replace the parts with new ones because you have no idea how many times the bore had been honed out. Use silicone break fluid and carry a spare rebuild kit wherever you go.

Good luck.

 

Another quick note, I rebuilt my Master Cylinder and Slave Cylinder and, from experience - just buy new ones. Do what t_g says and do the Master, Line, and Slave at once and you should be golden. I'm going to be going with a steel braided line next for looks and performance.

 

I wouldn't worry about it until you have an issue (likely you'll grind a gear every now and then). Dark fluid isn't a sign of component failure or likely component failure, just contamination. If you really want to solve the problem, replace the entire system with new components. But you might as well wait until it fails, it might last a long time still.

My 240SX used to cook the brake and clutch fluids to black within a couple of days when driving on the track. Pedal never got spongy, gears never clattered, so I never worried about it.

 

back to the original question "is black clutch fluid a problem?" No it isn't. Mine turned black 8 years ago , a few days after I replaced the slave/master/lines of the clutch hydraulics.

I think it gets black so quickly because the slave cylinder in mounted on the engine, which gets hot.

And if you replace the clutch brake fluid , sometimes the seals get destroyed as they rub on the rough oxidized metal that normally sees no wear. I've done that too.

 

Thanks guys. I did replace the whole clutch system with new parts, even the hard line, but not all at once - within a month anyway.