I have an 84 civic with brand new integra master cylinder and brake booster, the car runs fine except when driven for a couple of miles the brakes gets stuck and do not release for atleast 20-30 minutes, by removing the check valve that is on the vacumm line that goes to the booster it releases the brakes and everything works perfect for a couple of miles more, the thing is that I test the check valve and it seems to be ok. What could be the problem?

 

sounds like your brake pedal is out of adjustment causing your MC/booster to clamp up your brakes