What would cause the fluid in the clutch resovior to turn brown ?

It's my understanding that the stuff in the reservoir oxidizes over time, which is what causes it to become darker.

When was the last time you flushed it out with fresh fluid?

Time.

The car was my dad's and it has to have been 5 years since any work has been done to the clutch system.

The car was my dad's and it has to have been 5 years since any work has been done to the clutch system.

In the words of Jamie and Adam, "Well, there's your problem!"

It's turned darker because it has absorbed moisture over time. With brakes, it is important to flush out the fluid every two years or so to prevent rust from forming in the system.

The same rust can form in the clutch sytem, but you're really only talking about the clutch master and slave cylinders versus all the components in the brake system.

Although, manuals will tell you to flush the clutch system on a regular basis too, if all is working correctly then I would leave it alone. I know that advice is contrary to what the manuals will tell you and maybe even members on this board, but it's good advice. My experience has been that if the fluid hasn't been changed in a long time and you decide to flush it, that's when the problems start. I got this advice from a very knowledgable Z mechanic and it's worked for me.

I'll clarify that advice a bit. If you have been flushing the clutch (or brakes) regularly from new, that's fine. But if they have never been flushed, or it has been many years since the last flush, don't start now.

What happens is that crud will build up in the cylinders over time. If you flush regularly from new, the crud is cleaned out regularly and kept to a minimum. But if the crud is allowed to build up and harden over several years, a flush won't remove it but will only move it around to where the piston seals have to run over it and you suddenly have a failure shortly after the flush.

Since i am having a problem with my clutch, it seems that the best thing to do is replace all components like i did with the brake system.

I'll clarify that advice a bit. If you have been flushing the clutch (or brakes) regularly from new, that's fine. But if they have never been flushed, or it has been many years since the last flush, don't start now....

That's interesting advice Arne, I've not heard that before. If one's fluid flushing history is suspect, how should the fluid be changed? Should it all be pumped past the bleeder nipple; adding fresh fluid when empty? Or, should the lines be removed ahead of the caliper/slave?

The failure point for this type of problem (both for clutch and brake hydraulics) is typically the master cylinder. It happens more often with brakes than clutch, but both are susceptible. So removing the downstream parts doesn't help.

In the case of the brakes especially, you don't want to press the pedal (and therefore the master cylinder piston) farther than its normal amount of travel. Doing that will run the piston seals over the sludge that will have built up inside the cylinder bore. So your best bet is to not stoke the pedal if possible - use either gravity bleeding, vacuum bleeding or a pressure bleeder. Anything that will allow you to change the fluid without having to push the pedal.

I am going to replace the master cylinder, slave cylinder and hose ( it has more cracks in it than my old face ). My question is i have priced around and have found the whole gambit of prices, what exactly is the difference between a $50 and $20 master cylinder ? Are they that much better ?

$30 (sorry, someone had to give the smart-arse answer)