Q: brake pedal goes straight to the floor after replacing all 4 brake lines and pads and calipers

This brake system has an anti-lock (ABS) system. This system prevents wheel lock-up during a hard braking event to came tire contact area on the road and effective. When air is introduced to the brake system it can get trapped in the hydraulic modulator, which is a component of the (ABS) system.

When there is brake bleeding in this system, a scan tool is required to activate the modulator’s brake channels to open and remove the trapped air. Another type of failure is the master cylinder leaking internally. Brake fluid over time degrades and can cause seals to fail. This fluid should be flushed as a maintenance item, depending on years of service. Since you shouldn’t be driving without working brakes, I recommend having a certified technician, such as one from YourMechanic, come to your car’s location to inspect your brake system and let you know what repairs need to be made.