what I would do is get some brass male inverted flare plugs & cap the MC ports & if the MC is bled out and it is holding pressure the pedal will be rock hard with virtually no travel (eng idling-these are PB correct?). the fittings are 9/16-20 and 1/2-20 & your parts house would have em in the "Edelman" fittings cabinet. then onto the prop valve & I would unscrew the rear brake(s) "out" line & cap the prop valve female open port with a 3/8-24 similar male brass fitting & work on the fronts & see if you can get them bled out and have the same high and tight pedal that you have with the MC capped. that'd be a good start. I would put a block of wood under the pedal so it dont go to the floor but stays pretty close to its normal range of travel. holler back when you can