Hi and thanks for using 2CarPros.com.
If the pedal goes all the way to the floor, either the brake shoes are installed incorrectly and not attached to the wheel cylinder, there is broken line or hose or the master cylinder is bad.
Here is a link that discusses what can cause a brake pedal to go to the floor:
Here is a link that shows how to replace rear brakes shoes. Review it to see if there is anything you missed.
Check that and let me know what you find or if you have other questions.
Wednesday, August 22nd, 2018 AT 5:07 PM