In addition, if you happened to have a Quick Take-Up master, you'd have to assure that the pressure-relief valve in the rear reservoir is working properly, bypassing at the correct pressure.
I didn't think the Hydroboost was ever paired with Quick Take-up MCs, or even compatible with any for that matter? I did consider the possibility that one or both of the remanufactured callipers I used could be Quick Take-up though, but if that were the case I don't understand how I could have had a good pedal feel immediately after the swap from vacuum.
Admittedly I don't understand much about the actual valve function differs in each style of MC. I do know the Quick Take-up has a higher initial volume of fluid
I don't know what an "ABS bypass valve" is.
I don't actually know if that's what I'm feeling, more of an educated guess.
When the pedal is about 3/4 the way to the floor there's a noticeable "click" in the pedal as it travels maybe 1/4 an inch with 0 resistance before regaining pressure. When this happens the brake warning dash light comes on (same one as when you have the park brake engaged) and there is immediately more pressure at the brakes.
This is why I was so convinced my issue was air in the ABS system. Once I'm moving again I can tap the brakes again lightly, I'll feel the same "click" in the pedal, and the brake warning light will turn off. There is noticeably more braking pressure when the dash light is illuminated, but by the time it comes on the pedal is so far through its travel there's practically no boost left