After sitting too long with lines disconnected at the dual reservoir master cylinder w/o using, it seems the MC is ignoring the plunger. The pedal goes to the floor. It will bleed some fluid from the front and rear reservoirs but the pedal won't firm up. It just goes to the floor.

Check valve or something else stuck? Time for new MC? Just keep bleeding?

Thanks.


1948 3/4-Ton 5-Window Flatbed Chevrolet

34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.