1996 Chevrolet C2500 Pickup Brake Service (ONLINE REPAIR MANUALS)

Single Diaphragm Type

Disassemble

• Remove boot, silencer, vacuum check valve, grommet and front housing seal, Fig. .
• Scribe a line across front and rear housing, then mount brake booster to brake mounting fixture tool No. J 23456 or equivalent, Fig. .
• Turn fixture handle counterclockwise to unlock housings.
• Remove return spring, power piston assembly and power piston bearing from rear housing, Fig. .
• Remove reaction body retainer, piston rod, reaction retainer and filter.
• Remove power piston and pushrod assembly as follows:
• While holding the pushrod down against a hard surface, ...

Height Sensing Proportioning Valve

The height sensing proportioning valve must be adjusted whenever the valve and/or linkage is disassembled or removed for service. In addition, adjustment should be checked if excessive front wheel lock-up is experienced with a lower than desired brake application rate when vehicle is at or near maximum GVWR.

• Raise and support vehicle leaving wheels on, and allow axle to hang freely.
• Remove lever retaining nut and disconnect lever from valve shaft, Fig. .
• Rotate valve shaft to permit installation of correct adjustment gauge, Fig. , ensuring that D shape...

Duo-Servo Brakes

Removal

• Raise and support vehicle, then remove tire and wheel assembly.
• Remove brake drum. If brake lining is dragging on brake drum, back off brake adjustment by rotating adjustment screw. Refer to individual truck chapter for procedure. If brake drum is rusted or corroded to axle flange and cannot be removed, lightly tap flange to drum mounting surface with a suitable hammer.
• Using brake spring pliers or equivalent, unhook primary and secondary return springs, Fig. . Observe location of brake parts being removed to aid during installation.
• Remove brake hold-down spri...

In order to properly service power brake systems, a thorough understanding of the power assist system is necessary. These systems provide a mechanical assist, acting to increase the force applied to the master cylinder piston by the driver while decreasing the effort necessary to obtain acceptable stopping performance.

Hydraulic assist units incorporate a basic open center spool valve, hydraulic cylinder and an accumulator assembly in a common housing. When the brake pedal is depressed, the hydraulic piston moves forward closing off fluid relief passages, the spool valve applies flui...

Brake System Bleed

1992-95

Electro-Hydraulic Control Unit Brake Pressure Modulator Valve (EHCU/BPMV) Module

The EHCU/BPMV Module should be bled after replacement or if air is trapped in the unit. If bleeding is required, the module must be bled thoroughly before the wheel cylinders and calipers.

There are two bleeders on top of the unit that appear to be normal bleeders, Fig. . These are modulator bleeders and must remain closed when the unit is not pressurized.

The internal bleeders are on either side of EHCU/BPMV module. The valves are used to open the internal passages within the E...

When working on or around brake assemblies, care must be taken to prevent breathing asbestos dust, as many manufacturers incorporate asbestos fibers in the production of brake linings. During routine service operations, the amount of asbestos dust from brake lining wear is at a low level due to a chemical breakdown during use, and a few precautions will minimize exposure. Do not sand or grind brake linings unless suitable local exhaust ventilation equipment is used to prevent exces...