Hey...I have a 91' Chevy S10 Blazer, and the front brakes failed with the pedal going all of the way to the floor and the Blazer not stopping. I replaced the master cylinder, added fluid, and bled the brakes. Now, the brake pedal is spongy, and I can't get it to get hard. I have bled the brakes over and over again with the same result. I do not see any leaks. Does anyone have any other ideas? Might it be the Brake Power Booster? Please help ;0)

 

*Moved to '1st Gen Tech'*

 

if it was the brake booster, you would hear a hissing sound when the pedal is all the way to the floor I believe?

 

Did you bench bleed the master prior to installing in the truck? It must be done as per instructions that came with the new master.