I just went through this with a VW sand rail. Two wheel cylinders were frozen, the car pulled hard to one side. I replaced all 4 wheel cylinders, shoes, and drums. Also replaced the MC, it had a ton of corrosion from NOT replacing the fluid. It was a 3/4" single action Wilwood with integral reservoir. All steel lines were solid and I replaced the hoses a couple years ago, they are still very pliant.
The only weird or different thing was a CNC cutting or turn brake(turn brake still works but buggy is only street driven). Even following the CNC bleed procedure, we still had a low pedal after a WHOLE QUART of fluid. On second pump the pedal is plenty high and hard. But that low pedal on first pump is pretty scary.
At this point, the only fix can be to remove the turn/cutting brake, and install a Tee where it was. I also bought a 10 pound residual valve just in case we can't get a good pedal. It had a good pedal before after I changed all the hoses and adjusted the shoes.
Also he had almost no clutch, hydraulic not cable-operated. It had a 5/8" Wilwood MC and an old(ancient?) 7/8" Neal slave. The MC insides looked bad, and the slave was even worse. The pitting looked like craters inside. Replaced them both and that pedal came up nice and quick after little bleeding.
Well, at least the clutch was easy.