Thanks for the replies.
I'll check for play at the plunger arm. Is that adjustable? Is that the toeboard clearance adjustment in the manual?
I flushed the system with the wheel cylinder bleeders. The pedal still seems hard with the bleeders open, though after a few pushes it would go most of the way easily then get stiff maybe 75% of the way. I'm trying to remember if that happened only on the rear wheels.
What would I check on the MC?