My 79 had brake pedal to the floor, so my son and i investigated and found leaking rear calipers. So we installed new calipers, pads and rotors (as they were very worn) today. All great. Then we bled them, and bled and bled. We used over a litre of fluid. For hours. We could get firmness to the pedal during pumping, but when the engine is on, pedal straight to the floor. What is happening!? Thanks Peter in Queensland Australia.