I wanted to tackle the brakes next on my car. so i removed the entire pedal assm. with abs componets attached. i removed the resivor and cleaned that. i also removed the 3 brake lines at the bottom and also removed the celiniod? pack to get at the 3 o-rings. I used a brake cleaner and flushed out the master cyclinder and and ports in valve block. I put it back together. I have a few knowns and some unknowns. 1st my pedal fades with the acc. pump running as soon as i touch the brake pedal. seems like i need a new accumulator ball because the pump pulses at 30 secound intervals with out touching the pedal. My biggest issue is that i cant get any fluid to pump from the port that feeds the drivers side front wheel. i even tried it at the valve block thinking I had a bad rubber brake hose. not the case. I also removed and cleaned the electric valve at the end of the master cylinder. the screens were plugged as well as the tiny little hole in the center of the brass insert. I dont know much actually very little about the brake system., are these control valves replaceable singlely or is it a complete replacedment of the whole deal? i think I am goinf to go with the gm accumulator due to the cost, do you know what cars these come on gm's? also would it be ok to get one off a junk yard jag or is that one probablly bad also?