K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Vacuum Brake Booster: Description and Operation
Single Diaphragm Type
Fig. 1 Exploded View Of Delco-Moraine Single Diaphragm Power Brake Unit
Fig. 2 Exploded View Of Delco-Moraine Single Diaphragm Power Piston Assembly
DESCRIPTION
These power brake units, Figs. 1 and 2,
are a combination vacuum-hydraulic brake booster of the vacuum suspended type which use engine intake manifold vacuum and atmospheric pressure
for its power.
These units consist of a vacuum power section and an hydraulic master cylinder section. The vacuum power section contains a power piston with
rolling diaphragm mechanism and power piston return spring.
The control valve is made up of an air valve and floating vacuum control valve assembly. The reaction mechanism consists of an hydraulic piston,
reaction plate and a series of levers. The valve operating rod, which operates the air valve, projects from the power section and is connected to the brake
pedal linkage.
