ABS Braking-Build Pressure

Fig. 13 - Build Pressure - Hydraulic Control:

ISOLATION VALVES

Closed, isolating wheel brakes from master cylinder primary and scondary fluid supplies and open to booster servo circuit pressure through open build valves.

DECAY VALVES

Closed
BUILD VALVES

Open, allowing booster servo circuit pressure to flow to wheel brakes through the isolation valves.

POWER ASSIST

The boost control valve shuttles between its three positions to provide power assisted braking.