brake help please

history. the duster(73) has not moved to much, life has been busy I went to take for a short drive after I used the brakes I noticed the front's were dragging(dics) so I thought lack of use & age the pin's or piston's might be seizing up so I pulled the caliper off lubed the pin's applied the brakes to see if the piston's moved they did. I moved pushed the piston back replaced the shoe's & caliper when I applied the brake's I got some pedal and caliper gave pressure to the rotor the when I applied the second pedal went to the floor & no pressure to the rotor after waiting about five min. tried again I got some pedal first pump nothing the second time thinking air in line's waited then applied brake loosened bleeder fluid shot out second pump nothing. now thinking back one time when I pushed the pedal I heard a loud sound like a spring breaking & the pedal just dropped hitting the brake switch causing the break light's to stay on. thinking it might be I master problem (manual)I removed it on the bench applied pressure to the piston it has pressure when I pushed it in shot fluid out the lines & spring's back, is it time for new master , why after waiting some time would I have pedal then nothing thank's