2008 Chevrolet Express 3500 Brake Service (ONLINE REPAIR MANUALS)

Accessing Diagnostic Trouble Code

Connect a suitably programmed scan tool to Data Link Connector (DLC) and follow manufacturers instructions.

Diagnostic Trouble Code Interpretation

Refer to "Diagnostic Tests" for trouble code identification.

Connector Pin Identification

Refer to Figs. through for connector pin identification.

Diagnostic Tests

Tahoe & Yukon Hybrid

Envoy, Rainier & Trailblazer

Express & Savana

Sierra & Silverado Classic

Symptom Tests

Tahoe & Yukon Hybrid

2008

Refer to Figs. and for symptom tests.

Envoy, Rainier & Trailblazer

Refer to Figs. through for symptom tests.

Expre...

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...

Acadia, Enclave & Outlook

• Apply park brake, then with engine off, apply and release brake pedal several times until brake pedal becomes firm to deplete vacuum reserve in vacuum brake booster.
• Remove air cleaner assembly.
• Disconnect master cylinder fluid level sensor electrical connector.
• Remove vacuum brake booster check valve and hose assembly from vacuum brake booster and position aside.
• Remove vacuum brake booster vacuum sensor and position aside.
• Release front and rear brake pipes from routing clip on frame rail.
• Remove Brake Pressure Modulator Valve (BPMV) assembly mount...

Manual Bleed

• If vehicle is equipped with power brakes, remove vacuum reserve by applying brakes several times with engine off.
• Fill master cylinder reservoirs with suitable brake fluid. Ensure to always keep master cylinder reservoirs at least half full during entire bleeding procedure.
• If master cylinder is suspected to have air in bore, it must be bled first. To bleed master cylinder, proceed as follows:
• Disconnect forward brake pipe connection at master cylinder.
• Allow brake fluid to fill master cylinder bore until it begins to flow from forward pipe connector port.
• Connect and ...

The caliper mounts in a way that allows the caliper to move laterally inboard as the brake pads wear. The caliper housing is a one piece casting with the inboard side containing the piston bore. The piston seal also acts as a return mechanism for the piston.

Applying the brake pedal causes the hydraulic pressure that moves the caliper piston. The piston then forces the inboard brake pad against the inboard braking surface of the rotor. Increasing the force against...

Brake Lines & Linings

Remove one of the front wheels and inspect the brake disc, caliper and linings.

Do not allow any oil or grease on the linings. It is recommended that linings be replaced in sets when worn or damaged.

If the caliper is cracked or fluid leakage through the casting is evident, it must be replaced as a unit.

Brake Roughness

The most common cause of brake chatter on disc brakes is a variation in thickness of the disc. If roughness or vibration is encountered during highway operation or if pedal pumping is experienced at low speeds, the disc may have excessive thickness v...