why am i still not building pressure in my brake system?

I had to replace a rear rotor and pads due to a pad partially slipping out of the rotor and destroying my rotor.(rear passenger side). got it all assembled and bled the system no air just fluid and put it all back together. turned the car on and the peddle went to the floor. Tried bleeding while car was on still the same results. Replaced the master cylinder bench bled it and had no air bubbles. Had same results when I bled the rest of the system. ABS sucks. Sorry dont have money to donate it all goes to the cars so i can get to work.