not a matter of "enough" pressure in a hydraulic system, either is pressure or isn't ..... hard to believe all 4 wheel cylinders would corrode so solid none will move, but if you pressed the brake pedal with a drum off and that cylinder didn't move, at least that cylinder is seized, try it with both drums off each side - push pedal gently/slowly, have someone watching to see if the shoes move, might have been a good idea to put kits in the wheel cylinders while doing the MC
Bill
