About a month ago, I replaced my master and slave cylinders, and as a result replaced the fluid.
I noticed today that it's already starting to discolor (turning quite dark).

I know our cars have a tendency to "eat" clutch fluid, but this seems excessive. I'm also unclear as to why it's discoloring so quickly. I'd usually only expect to see dark fluid due to water absorbsion, but given that it's nearly brand new and that the master/slaves are new as well, I don't see how it could have absorbed much water already.

Perhaps I'll flush it again and use some synthetic fluid on the off chance it'll help...

 

I also was concerned about how much the oem clutch fluid became discolored with debris in the reservoir. I also think it was a factor in the leaking master cylinder. After changing out the fluid/cylinder, I put a 'sock' around the cap, something like what Spoon sells. The fluid seems to darken relatively slowly now, with no deposits showing up in the reservoir.

 

I believe the fluid is breaking down rapidly due to the close proximity of the Exhaust manifold to the bellhousing of the trans. Mine gets pretty nasty in a matter of months.

 

I think you're probably right, which means there's not much to be done I suppose, other than flush it often.

 

This darkening seems to be most rapid on new cars and as just shown here, with new master and slave cylinders. I have noticed that subsequent flushes do not darken quite as rapidly. This leads me to believe that there must be a rubber ring on the piston of the cylinders which leaches out material when newish. And once it has done its initial leaching, it tends to slow down somewhat. I cannot confirm this. It's just a guess.

 

 

I don't know, On all the S's I have serviced over the past 4 years, All models 00-03 have been pretty dark/black and contaminated after approx. 4 months. I'm no engineer, I just work on em'. Maybe Road Rage has some brake fluid tech to share.

 

After bleeding my clutch fluid, after just one month it is dark again. You can bet I was pretty surprised...

 

 

If you look at why the fluid is dark, you will see actually tiny pariticles that are both floating around and stuck to the sides of the reservoir. Heating and cooling of the fluid and water getting into the fluid will not account for this. This material came from somewhere and since the seals of the piston and the rings of the plunger are black, that's why I'm guessing they may be involved.
If someone has a test stick for brake fluid water content, dip it into newish fluid that has gone dark and I'm going to bet that the water content is still acceptable.
Personally, I don't like the fact that my clutch fluid goes dark like that but logically, it should still function OK.
Now, another weird thing: How come the brake system fluid doesn't go dark as fast? It's the same kind of fluid. Does the pistons not use the same kind of seals?