I decided to try out the black magic pads, new centric premium rotors and calipers on my 2000 XJ. While pulling the front brakes apart I noticed the inside of the rotors didnt look like they had been getting pad pressure. They were all rusty and pitted but the outside of the rotors looked normal. Does anyone have a clue as to what would cause this? It would explain the lack of breaking power I have but I am wondering if I may have a master cylinder or prop valve issue. I want to make sure I get that addressed before I slap all new parts on.