Ok so basically I lost all the power in my pedal, having to pump up and push the brakes extremely hard. I replaced the master cylinder and got normal pedal feedback, however after driving and braking a bit the brakes completely lock up after sometime, after a few miles. To the point they completely lock up and the car will not move and the brakes are hard to press (full of pressure). After you let it sit for a while they release pressure and you can drive it again until it happens again. It's almost as if it keeps building and building pressure.

We are thinking that the master cylinder may not have enough movement to hit the "valve" part that releases pressure. Does this sound right? also since you cant really adjust the master cylinder, is there a way to adjust the pedal in/out that anybody knows? I've tried two master cylinders thinking i got a faulty one. Any help would save me!!!! Please help!!! Lol