Brake pedal soft and goes all the way to the floor

Does the car have anti-lock brakes? If it does, you will likely need a scanner to command the computer to open two valves to allow those chambers to be bled in the hydraulic controller. Air gets into them if you allow the reservoir to run empty or if you bleed at the wheels after replacing the master cylinder, or if you did not bench-bleed the new master cylinder. Once we have this solved, I can share a simple trick so you do not have to bleed at the wheels.