2005 Chev Blazer, 4x4 auto
had seized front pass caliper. Replaced both front calipers. While replacing I broke the line from front pass to abs pump. Replaced line. Master cylinder never went dry. Began bleeding process with friend, it was at this point I noticed the pedal would get stiff after pumping but where it would normally stop until a screw was cracked, allowing it to push to the floor, mine 'pushes through'. It does not simply drop to the floor but rather I can hear, and feel a (soft click/pop?). Hard to describe. Video can be seen here. It resists a little then allows the pedal to go to the floor. I chalked it to air and continued.

The rest of this is added to save some potential suggestions that I've already tried. I believe the pedal is the issue. Had a bad time getting fluid out of the rear passenger caliper. No luck with friend's foot, hand vacuum could get only tiny drops of dark sludge after literally days of trying. Got tech 2 and preformed abs bleed. No real change. Tried pneumatic compressor powered vacuum and after hours, still only drips of dark. Replaced the brake line to the rear from abs and finally was able to pull fluid using vacuum. Good clean fluid. Teflon tape on bleeder screws to prevent air pulling around it. Vacuum at best pulls a steady but slow stream of fluid. The fluid fills the bottom 1/3 of the clear tube. It will occasionally sputter a larger flow briefly. After hours of pulling this situation hasn't changed. I am getting air with some fluid, not fluid with air bubbles.

Is my brake booster or master cylinder shot? Neither has any sign of leaks