On a toughie I plug the MC ports with a pair of brass inverted flare male plugs from the Edelman fittings cabinet at your parts house. If the booster, round nub pushrod clearance, MC piston seals, MC itself bled out, all of these are OK then at this point with it capped, the pedal will be rock hard with virtually no travel (eng idling). try light pressure and try a heavy stomp. that'd be how I would start & the fittings are cheap & you will reuse em in your career. we gotta pin this down a bit.