The only way you are going to have a pedal go to the floor is due to loosing pressure via a leak either internally or externally. I assume you have not found any external leaks which means we are allowing pressure to bleed off. When you bleed the brakes are you getting fluid to squirt out at each caliper?
What I suspect we are going to have to do is cap off each port from the master cylinder and operated the pedal. With no brakes lines you should have a firm pedal. If not then the master cylinder is the issue.
If you do have a firm pedal then add in one port at a time until you find it dropping to the floor again. Once it does you know which leg of the system is the issue.
Let me know if you have questions. Thanks
Sunday, August 23rd, 2020 AT 3:05 PM