Okay so starting from the beginning. I've had problems with my brakes for quite a while. I had someone install brand new rotors brand new brake lines brand new brake pads but new calipers and a brand new master cylinder to try and fix the problem. After driving for 2 weeks the brakes began to stick once again. I have determined that it is the master cylinder causing my problems. After tapping on it, the brakes let go.The brakes stick every other trip, but do not stay stuck. The drag is slight to severe at times. When severe, it is hard to reach 40 mph. Master cylinder is new so why is it failing? Both brake sides on front are siezing. I'm stuck at a hotel for the night and drinking some beer writing this.
I'm out $1000 after my recent brake job and I need some help here. Why are my brakes still acting up? I just got married and this is happening on our honeymoon. Sucks. It only seizes up once in a while sometimes bad, sometimes not too bad. Most times, I can pull over and let it cool and it'll let go. What's going on? My mechanic says it might be leaking fluid into the booster. I don't know but I need someone who knows what to do.

 

I would start by looking at the portioning valve or abs modulator. Try taking the fuse out of the abs fuse socket and see if that helps.

 

what is the vehicle, model year engine, abs or non, fwd or rwd, rear disc or drums

when the problem occurs get out and check each wheel for heat build up. I measure each wheel with a temp gun. Are all the wheels hot or just front or just rear

when the master was replaced...does the rod that actuates the mc have an adjustable rod length...if the rod is to long the brake pedal will have no free play and the master will not open enough to let the fluid back into the master to relieve fluid pressure. this is all speculation without knowing what type of vehicle you have.

 

The truck is a Chevy Silverado 5.3 liter 2 wheel drive. The front brakes stick I did not check the back brakes. When it sticks bad it shakes and the heat build-up is substantial. I have to tap the master cylinder with a small Hammer to make it let go.