Well, I parked my camaro for a few months to swap my 6 speed for an auto (long story) and ever since I did this, my brakes suck. I'm not sure how this happened since I didn't touch anything with the brake system. I figured maybe the master cylinder went bad from sitting so I went ahead and went through the whole system and rebuilt the rear calipers, replaced all the rubber hoses, and put a new master cylinder on the car. I have bled the system 5 times now, and even purchased a power bleeder and did that today but nothing has helped. There is no air and the pedal is really stiff while bleeding but as soon as I start the car, the pedal becomes really soft and pretty much goes to the floor when trying to stop.

The car is a factory 4 wheel disc (non 1LE) with a 4th gen rear and stock front brakes. The brakes worked great before I swapped the trans so I am at a loss. Is it possible the prop valve went bad? Or maybe the booster? I've always been told if the booster goes bad, then I would have no power assist so I doubt this is the problem. And if the prop valve went out wouldn't I still have good pedal?

 

have you tried bleeding it with the car running?

 

I have not. I've thought about it but I've never had to do that on a car.

 

IDK why, but i always bleed with the car running. i'm not sure if it's nessecary, but my thought is the power booster would have more pressure. cant hurt to try it.

 

Did you bench bleed the master cylinder before putting it on? If you did not take the short clear brake line kit that came with the master cylinder then disconnect the brake lines. Connect the clear hoses and put the open end of clear hoses into the reservoir of the master cylinder and pump the brakes until no more bubbles come out

 

Yes I bench bled the master.