C 2500 Suburban 2WD V8-454 7.4L VIN J SFI (1998)
Vacuum Brake Booster: Description and Operation
The vacuum booster is a tandem diaphragm vacuum suspended unit. During normal operation, with the brake pedal released, manifold vacuum is applied
to both sides of the diaphragms. Applying the brakes allows air at atmospheric pressure to enter one side of each diaphragm. This pressure difference
provides the power assist.
The booster assembly is located on the left front cowl. The master cylinder mounts on the booster assembly.
A pipe located on the left side of the intake manifold supplies vacuum to the vacuum booster. A flexible hose connects the pipe to the booster check
valve. The check valve mounts in a grommet on the front of the booster assembly.