Rev's problem might be a screwed up or intermittent lateral 'g' sensor.
(Control unit doesn't know that the car is being cornered and thinks
it's a straight line skid.)  Might be worthwhile to see if this happens
in both left and right cornering.  Great Saturday morning workout on a
big empty parking lot.

Not enough clues on Mike's issue:  Could be a test sequence if the
engine had just been started--a pedal pressure change is normal during
test but the pedal going to the floor is wrong.  Can't tell whether the
problem is happening after the car had been driven above 8 mph (once
it's gone through self-test and arming) or if this happens right after
the car is started and first moved (ABS unarmed).  Maybe too, this is a
brake booster problem that's firming up the pedal making it feel like
it's against the bottom stop.  The human critter isn't much good at
sensing control positions but is damn good at sensing force.

First off, make sure all three warning lights are working. Bleed the
brakes. Check the wiring to each wheel sensor.  Remove, inspect and
re-connect the cable connectors to the control unit--mine are typical
old-style Bosch connectors with unplated copper contacts--over the
years, oxidation builds up on the contacts.

There are resistance checks for the lateral 'g' sensor and wheel sensors
but each must be disconnected otherwise the juice from the ohmmeter will
destroy the old-fashioned solid state stuff in the control unit.  Better
to find a good brake shop that has a Bosch ABS diagnostic unit.  This
ABS control was used on several makes of cars including Chryslers of
late '80s vintage.  You can find good service at other than the dealer.

HTH.... PJ