I replaced the rear brakes sunday and once finished we tested them and noticed that the pedal was still very soft. so he bled all the lines initially all were good except rear passenger side was a trickle. so we repalced the master cylinber. after repalcing it we went back and bled the lines again and now perfect flow from two and a trickle out of the others and there is black stuff coming out of one. and my pedal is way to soft. takes a lot for me to stop. No calipers were repalced