Section 11 (Anti-Lock Brake System - 4-Wheel): Description

WARNING: This page does not describe the selected car, but rather 58 other vehicles, including the 1992 Oldsmobile Bravada, 1992 GMC Yukon, 1992 GMC Suburban, 1992 GMC Sonoma, and 1992 GMC Safari. However, it is still accessible from the selected car via links, so may be relevant.

The Kelsey-Hayes 4-Wheel Anti-Lock (4WAL) brake system is used to prevent wheel lock-up during heavy braking. This allows driver to maintain steering control while stopping vehicle in shortest distance possible. The system consists of Electro-Hydraulic Control Unit (EHCU), 4 wheel sensors, warning lights, electrical wiring and hydraulic lines.

The EHCU consists of an Electronic Control Unit (ECU), hydraulic control unit, 2 accumulators, pump motor and a relay. See Fig 1, Fig 2 or Fig 3. The hydraulic control unit consists of an Isolation Solenoid Valve (ISO), Pulse-Width Modulated (PVM) valve, a High Pressure Accumulator (HPA), Low Pressure Accumulator (LPA) and a reset switch on each channel. If overhaul or repair to any component on the EHCU is necessary, complete assembly must be replaced.

Fig 1: 4WAL Brake System Component Locations (Astro & Safari)

Courtesy of GENERAL MOTORS CORP.

NOTE: Figures 15 & 25 are Courtesy of General Motors Corp.

Fig 2: 4WAL Brake Sys Series Component Locations (Bravada, "S" & "T"

Courtesy of GENERAL MOTORS CORP.

Fig 3: 4WAL Brake System Component Locations ("C" & "K" Series)

Courtesy of GENERAL MOTORS CORP.