I was bleeding my brakes/clutch last night and noticed that the fluid reservoir was coated with black crap from the old fluid. My question is do you guys clean the inner walls of the reservoir somehow when bleeding the brakes to remove the coating/film from the old fluid?

I cleaned mine the best that I could when I flushed the fluid and replaced it with new. I cleaned what I could out of the reservoir, and then put new fluid in the reservoir. Even so, after pumping the brakes a few times, the fluid became dirty again. I kept flushing, adding, draining, pumping, flushing, etc over and over until I finally got everything relatively clear. I probably used at least half a gallon of fluid before I was satisfied.

When I worked for a VW dealership, it was customary to remove the plastic resevoir from the master cylinder and clean it with brake clean when doing a brake fluid flush. Sometimes the "O" rings where the resevoir attached to the master needed to be replaced once they had been seperated.

I have attempted to do the same with a Ford master cylinder, after finding the fastner that holds them together and removing it, but it did not want to seperate easily and I did not want to buy a new master if I did not succeed. I kept meaning to try it on an old master that was being replaced, but never did.

If it really bothers you, you could take the entire master cylinder off the car so you could turn it upside down and rinse several times with brake fluid until you got it clean. I would not use brake clean unless you could seperate the resevoir so that you could make sure that you did not contaminate the master with cleaner. If the resevoir were off, it could be air dried well enough to not be a problem, but I wouldn't risk using brake cleaner with the resevoir still attached.

Otherwise, keep flushing it until you are happy with the level of cleaniness, or flush it again soon.

I was thinking about flushing again with my next oil change, thanks for the advice.