question about brakes?

[sam's 72]

I am going to replace my intire brake system on my 72, power booster master cylinder, all the way down to the rotors and drums, new brake lines, every thing. Who has the best parts for these trucks, I am not looking at whos has the cheapest, but the best as far as quality goes! Also, why does the brake fluid turn black as motor oil sitting in the master cylinder? Is there a brand of brake fluid out there that does not do this? I usually just use regular brake fluid, and man, my master clynder looks like someone poured burny motor oil in it, its not thick, just blacl and very nasty looking!
Sam