2004 Chevrolet Avalanche 1500 Brake Service (ONLINE REPAIR MANUALS)

The power brake unit is n...

Certain general service procedures apply, regardless of whether the brakes are vacuum or hydraulically assisted. Only top quality, clean brake fluid should be used. More seals and valves are used with power brake systems than with ordinary brakes, so an inferior brake fluid will do much more damage. For the same reason, ensure all dirt is kept out of the system. Additionally, on models with hydraulic assist brakes, care must be taken not to mix the fluids of the booster hydraulic system and brake hydraulic system as the fluids are not compatible.

If the power unit fails, the brak...

Master Cylinder

Some vehicles use a conventional tandem master cylinder with two hydraulic pistons operating in-line. The primary piston controls the front brake system and the secondary piston controls the rear brake system.

Other models use a master cylinder that operates the same as the conventional master cylinder, but also incorporates a quick take-up feature in the rear chamber to reduce excessive pedal travel which may result from increased fluid displacement required to move the low drag caliper piston out against the rotor.

The quick take-up uses a spring-loaded ball check val...

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...

• Raise and support vehicle, then remove wheel and tire assemblies.
• Compress caliper pistons until they bottom in bores using suitable clamp.
• Remove calip...

Removal

• Siphon ^2/3 of the brake fluid from master cylinder.
• Raise and support vehicle.
• Remove tire and wheel assembly.
• Compress caliper pistons until they bottom in bores using suitable clamp, Fig. .
• Disconnect brake hose at caliper by removing inlet fitting bolt.
• Remove mounting bolts and caliper.

Inspection

Should it become required to remove the caliper for installation of new components, clean components in denatured alcohol, wipe dry using lint-free cloths. Blow out drilled passages and holes using compressed air. Inspect dust boots for punctures or tears. If punctures or tears are...