Stop—brake Help

[Wobpb377]

Well I can’t stop since my brakes go to floor.

1986 suburban 7.4 with 13” rear so Jb7 brakes

Went for an easy job, replace rotor and pads. Did they and truck still pulled hard right when heavy braking. Replaced hard and soft line on driver side. Installed new master cylinder and bench bleed that with zero bubbles. Installed all that. Bleed/flushed entire system. Pedal is super fine. When to start it and pedal goes right to floor. Read could be brake booster—sourced and got one. Installed. Rebleed all lines and now bubbles. Pedal firm. Start truck boom pedal to the floor. Only brake components I didn’t replace was proportioning valve and rear wheel cylinders. And thoughts or tip to stop the pedal from going to floor when I start the motor?