F 250 4WD Pickup V8-7.3L DSL Turbo VIN K (1994)
Hydraulic Control Assembly - Antilock Brakes: Description and Operation
OPERATION
Sensing a potential wheel lockup, the Rear Antilock Brake (RABS) module will activate the isolation solenoid within the RABS valve assembly,
isolating the rear wheel cylinders from the master cylinder, so that brake pressure cannot increase.
If pickup potential is still present with the isolation valve activated, the RABS module will energize the dump solenoid within the RABS valve
assembly with rapid pulses to bleed off wheel cylinder fluid into an accumulator built into the RABS valve assembly, reducing rear wheel speed
and allowing the rear wheels to spin back up to vehicle speed.
The isolation and dump solenoids will continue to be pulsed by the RABS module to keep the rear wheels rotating during braking.
When the brake pedal is released, the isolation valve assembly de-energizes and any brake fluid in the accumulator is returned to the master
cylinder.
