Would a bad brake booster give you a soft pedal like how it would feel if you had air in the system. The reason I asking is my pedal feels like it has air in the system. I thought it might be the master cylinder so I put a new one in. I bled the cylinder but the pedal still feels the same. I forgot where I read this but if you have power brakes and you pump the pedal with the engine off the pedal should get hard quickly and when you start the engine the pedal should move lower. Am I correct on this. Well if you pump the pedal nothing happens it just goes to the floor. BTW the whole system has no leaks before or after I change the master. Any thoughts? Thanks

 

Bump^

 

did you rebleed the whole system after you changed the master cylinder? Are the bushings\o rings that hold the plastic tank on you master cylinder good? Did you reuse old break fluid(just not a good idea, it absorbs water)? Worst case scenario you bought a bad master cylinder and have to get another one.

 

Did you bench bleede the MC?

 

i have a soft peddal too, are thies cars suposto fell like a new chevy monte carlo in the brakes? like tap em and go though the windshield? or are they more of a more preaasure ya give the more preasure ya get?

 

I bled the master in the car. I didn't reuse the old brake fluid. I'm positive I got all the air out of the master (I had to refill the res a few times). I know it sounds like I have air in the system and maybe I do have some air in the system not enough that it would give you no pedal pressure. It feel like like someone cut the brake line. Or better example is when you do a brake job and forget to pump the brakes first. That first time you go to step on the pedal and it just goes to the floor. Thats what its like before I changed before and after I swap out the MC. I blew my motor one night drive it home, brakes are fine. Car sat for like a week before I had to move it and backing out of the driveway hit the pedal and nothing. Thought it was the master. Change the master same problem. BTW the old MC never lost and fluid. It was full the whole time.