Reserve System

WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1999 GMC Yukon, 1999 GMC Suburban, 1999 GMC Sierra, 1999 GMC Savana Special, and 1999 GMC Savana Camper Special. However, it is still accessible from the selected car via links, so may be relevant.

System consists of charging valve, accumulator valve and spring-loaded accumulator. Accumulator is integral with booster. System is open to pressure port of booster.

Charging valve has an orifice and ball check valve. Fluid from pump passes through orifice in valve, unseats ball check valve and enters accumulator. Ball check valve prevents reverse flow.

Accumulator valve is poppet-type valve held closed by accumulator pressure. If no pump pressure is available, an actuator on spool valve sleeve opens accumulator valve. Fluid pressure can also enter accumulator from boost chamber through accumulator valve, when boost chamber pressure exceeds accumulator pressure.

Pressure relief valve vents accumulator to pump return port when pressure in accumulator exceeds about 1600 psi (112 kg/cm² ).