So I just resealed all 4 calipers. System has been open for a week. Am I supposed to re-bleed the master cylinder?

I've power bled all 4 calipers, but the rear brakes do not work when depressing the pedal. Fronts work though. When depressing the pedal, I get active fluid flow at the rear caliper bleed nipples.
Rear brakes only work if I pump the pedal, plus the pedal feels like it has no resistance. Thoughts?? Mc dead and bypassing?