1973 Dart brake failiure

my dart did the same sitting for 10 years.
added fluid, short stroked (1/2 - 1" max) pedal, and quick release (toe under pedal) to fill the MC,
1-2 pumps, had tight brakes, no leakage
seems they (MC's ) often drain the rear but if you fill and short stroke the pedal they often come right back