Long story short, I been buildin the ranger for about 2 years now. Had all the brake lines off so the master went dry I guess. Anyway I got all my new lines hooked up and filled the master and gravity bled the calipers last saturday. Did the usual pump and hold and after 15 min I had awesome brakes I mean they were perfect. Drove around slightly to test them and everything was fine. Pulled back in the garage to finish up some other things and after a few hours I went to park it and realized my brakes were no good. Pedal to the floor. They would stop me but they are barely there. Figure I blew the master cylinder. Replaced and bench bled it and did the normal pump and hold and I got a solid powerful stream out of each caliper but the pedal is still very soft. Half ton chevy calipers at each corner. I can craclk each bleeder and fluid flows and I have zero leaks. What the hell gives here? Booster gone bad? Everything is new except it and they were perfect at first I just don't get it.