Illl try to make this as short as possible. 1-ton ford 95 model with a pedal that bleeds off(like a master cylinder problem). Replaced master cylinder (3-times) pedal catches then slowly bleeds off. Replaced rear ABS controller (on frame) still same pedal. Blocked off rear and front lines off of master cylinder. Stopped soft pedal. Hooked up and bled rear brakes still had good pedal. Hooked up fronts and pedal starts bleeding off. Thought it might be bad brake line swelling.
Replaced both front calipers and brake lines. Still pedal catches then slowly bleeds off. No loss of break fluid. Just loss a patience. Can take and pinch off one of the front brake calipers (by the rubber line) seems to slow soft pedal down. Any help would be great Thx

 

Did you bench bleed the new master cylinder correctly? That's my first thought.

Assuming that was done correctly, I believe the rear is drums-- correct? If so, make sure they are in adjustment. If they are way out of whack, they can reduce pressure just like you mentioned. (My Taurus had this issue).

 

Adjusted rear brakes e-brake works good. Did not bench bleed the master. They usually send a bench bleeder kit with the new master cylinder. I did just bleed it on the truck. I still fill it is a bad master cylinder.

 

I think that's the issue. As far as I know, you always have to bench bleed. If you don't have to, it's definitely a good practice.

I'd say try it and see what happens.

 

Pulled master cylinder Bench blead with kit. Still pedal goes away?????