1992 Chevrolet G20 VAN Brake Service (ONLINE REPAIR MANUALS)

Brake Drums

Any time the brake drums are removed for brake service, the braking surface diameter should be checked with a suitable brake drum micrometer at several points to determine if they are within the safe, oversize limit stamped on the brake drum outer surface. If the braking surface diameter exceeds specifications, the drum must be replaced. If the braking surface diameter is within specifications, drums should be cleaned and inspected for cracks, scores, deep grooves, taper, out-of-roundness and heat spotting. If drums are cracked or heat spotted, they must be ...

Accessing Diagnostic Trouble Codes

1992

Diagnostic trouble codes can be accessed by connecting a TECH 1 or equivalent scan tool or by manually grounding the Assembly Line Diagnostic Link (ALDL) connector. To manually ground the ALDL connector, connect a jumper wire between terminals A and H, Fig. , and observe the flashes of the brake warning lamp. Note the following when performing the Diagnostic Circuit Check to access diagnostic trouble codes:

• When terminals are jumped, count number of short flashes starting from initial long flash, include long flash in count.
• The count se...

Removal

• Remove caliper assembly as outlined above.
• Remove inboard pad with retainer spring. Dislodge outboard pad and position caliper on the front suspension so the brake hose will not support the weight of the caliper.
• Remove two sleeves from inboard ears of the caliper.
• Remove four rubber bushings from the grooves in each of the caliper ears.

Installation

• Lubricate new sleeves, rubber bushings, bushing grooves and mounting bolt ends with Delco Silicone Lube or equivalent.
• Install new bushings and sleeves in caliper ears. Position the sleeve so that the end toward the pad is flush ...

Except S & T Series w/VCM & VCM-A

This braking system, Figs. through , is designed to reduce the occurrence of wheel lock-up during severe braking conditions. To accomplish this function, the system regulates hydraulic brake line pressure by using an Electro-Hydraulic Control Unit (EHCU) module or a Brake Pressure Modulator Valve (BPMV). The EHCU/BPMV module has two types of valves: isolation valves, which maintain separate pressure for each front wheel and combine pressure for the rear wheels, and dump valves, which "dump" pressure to each front wheel separately and rear wheels comb...

When troubleshooting the anti-lock brake system, refer to "Wiring Diagrams" in "Vehicle Systems" and connectors, Figs. through ; these may be helpful in completing a visual inspection of all relat...

System Operation

This braking system, Fig. , is designed to reduce the occurrence of wheel lock-up during severe braking conditions. To accomplish this function, the system regulates hydraulic brake line pressure when a microprocessor, located inside the Electronic Brake Control Module (EBCM), determines one or more of the wheels is about to lose traction during braking. The EBCM will allow the hydraulic modulator to change brake pressures several times each second to provide maximum vehicle control. This system cannot increase brake pressure above the master cylinder pressure appl...