Yes, discard old, dirty fluid. Do not drink it.

Ok, so my understanding of how dirty = leak is like this. Dirty fluid has a lot of particles floating around. Some of these stick to rod as it slides through the seal. Not all of them get wiped off by seal, and these sort of push the seal up as they slide under the seal. This leaves a small gap, and fluid can leak out. Its as if the particles make the rod no longer round in that spot.

If fluid is dirty enough, for long enough, some of these either damage the seal or stick so thoroughly to rod they're staying put for life (or both). Hence only recourse is to replace MC (or replace seal and rod, but no rebuild kits available).

Keep fluid clean, mc lives long, leak free life.

 

change fluid every oil change, or when it gets murky, if you had alot of sludge you may want to do it 2-3 times between oil changes, thats what im doing and my fluid keeps turning greenish black, and yes i have done a gravity bleed, guess just cleaning up all this gunk in here

 

Well I replaced my CMC and did a full clutch fluid purge. Clutch engagement is better than it's been in the last 6 years I've owned the car. Fluid was awful.

 

My 15 year old CMC is leaking and I'm going to have it replaced - ordered OEM from Majestic, they really are the best. So, someone I know who works on Porsches said that when you replace the CMC in those cars you also should replace the slave because they tend to blow out if you just replace the master. Since nobody seems to have mentioned that here, I assume that replacing the slave at the same time is not necessary/desirable.

 

 

...and there is a good chance your MC didn't need to be replaced as well. Often leaking can be cured with clean fluid.

Once the new one is installed, at every oil change, suction all fluid out of MC resevoir, and replace with fresh. It will circulate through the system. Fluid will stay clean and you won't ave any more leaks.