Caprice Wagon V8-307 5.0L (1987)
Brake Master Cylinder: Description and Operation
Powermaster
Exploded View Of Powermaster Assembly
This Powermaster unit is a complete, integral power brake apply system. It consists of an electro-hydraulic (EH) pump, fluid accumulator, pressure
switch, fluid reservoir, and a hydraulic booster with an integral dual master cylinder. The nitrogen charged accumulator stores fluid at 510-675 PSIG
for hydraulic booster operation. The E-H pump operates between pressure switch limits with the ignition "ON".
When the pressure switch senses accumulator pressure below 510 PSIG, the 12-volt E-H pump operates to increase accumulator fluid pressure to 675
PSIG. When the brake pedal is depressed, fluid from the accumulator acts on the booster power piston to apply the master cylinder which functions in
the same manner as a conventional dual master cylinder.
