2002 Chevrolet Express 3500 Brake Service (ONLINE REPAIR MANUALS)

Disassemble

• Place accumulator compressor tool No. J-26889, or equivalent, around end of accumulator.
• Install nut onto stud as in. Fig. , then depress accumulator with a C-clamp.
• Remove retainer by using a punch.
• Release C-clamp and remove accumulator compressor tool.
• Remove accumulator, O-ring, retainer, plug and spring,. Fig. .
• Remove retainer, output pushrod, baffle, piston return spring and retainer.
• Cut off eyelet of pedal rod, then remove boot.
• Remove nut, bracket and bolts, then separate cover from housing.
• Remove piston assembly and seals.
• Remove spool valve, then the accu...

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

The power brake uni...

Astro & Safari

• Apply parking brake.
• Disconnect reservoir and power steering hoses from booster.
• Remove master cylinder to brake booster retaining nuts.
• Position and support master cylinder away from booster.. Do not remove hydraulic lines from master cylinder.
• Remove booster rod from top of brake pedal.
• Remove booster mounting nuts from inside of vehicle.
• Remove booster assembly and gasket.
• Reverse procedure to install, noting the following:
• Torque booster mounting nuts to 27 ft. lbs.
• Torque master cylinder retaining nuts to 27 ft. lbs.
• Torque power steering hoses to booster n...

When wheel slip is detected during a brake application, the ABS enters anti-lock mode. During anti-lock braking, hydraulic pressure in the individual wheel circuits is controlled to prevent any wheel from slipping. A separate hydraulic line and specific solenoid valves are provided for each wheel. The ABS can decrease, hold, or increase hydraulic pressure to each wheel brake. The ABS cannot, however, increase hydraulic pressure above the amount which is transmitted by the master cylinder during braking.

During anti-lock braking, a series of rapid pulsations is felt in the brake pedal...

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