Brake behavior

[DK]

If you did bleed the brakes correctly without getting air back in to
the system, it should work. Did you run low/out of fluid when bleeding
by any chance? How much pressure did you apply with the pressure
bleeder as the limit is around 30psi. I would rebleed the brakes
manually to be sure, starting furthest away from the MC.
How long where the calipers/ lines disconnected for? Maybe lots of
fluid drained while disconnected, running the MC completely dry. It
shouldnt have affected the ABS, but the pulsing of the pedal could
indicate that a sensor maybe is at fault, activating the ABS, or the
ABS reservoir drained. (Not too familiar how the ABS works)

Regarding the brake bomb, sounds like it isnt quite working anymore -
hence the firm brake pedal before. It only works when the engine is
running, it gets pressure from the PS pump. Doesnt relate to the pedal
going to the floor.

Dave