I am baffled beyond belief. I have a 95 f-150 and the brake pedal goes to the floor. if you pump it it will get slightly hard, wait 2 secinds push pedal, right to the floor. i have bench bled master cylinder, bled brakes countless times, replaced master cylinder, one front caliper, and adjusted the rear brakes to the drum. one problem i think it might have is when you push the pedal air bubbles come up in the rear of the master cylinder tank. i don't know if there is a hole in the tank or the rubber is leaking by. any thing would be great!

 

Sounds like there is a leak in the line somewhere. You'll have to follow the line back to see if you can find a leak.

 

i found the problem! i bought a used master cylinder with a tank, and the air leaking back in the tank is gone. i have hard brakes! thanks for your help..