Vacuum Booster
Important:
• Replace all of the components that are included in the repair
kits in order to service this booster. • Lubricate the rubber parts with silicone grease in order to ease
assembly. The silicone grease is provided in the service kits. • Do not use lubricated compressed air on the brake parts. This
action may cause damage to the rubber parts. • If you remove or disconnect any hydraulic component, you may have
to bleed all or part of the brake system. • The specified torque values are for fasteners that are dry and
that are not lubricated. • Perform the service operations on a clean bench that is free from
all mineral oil materials.
This vacuum booster is a tandem vacuum suspended unit. When the service brakes are released during normal operation, the tandem vacuum booster operates with vacuum on both sides of the diaphragms. When the brakes are applied, air at atmospheric pressure is admitted to one side of each diaphragm in order to provide the power assist. When the service brake releases, the atmospheric air shuts off from one side of each diaphragm. The air then draws from the booster through the vacuum check valve to the vacuum source.
Routing
Brake booster vacuum hose (2) to engine routing in the 3100 series engine.
Vacuum booster hose routing in the 3800 series engine.
