Express 1500 RWD V8-5.3L (2008)
Brake Bleeding: Service and Repair
Hydraulic Brake System Flushing
Hydraulic Brake System Flushing
Caution: Refer to Brake Fluid Irritant Caution .
Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice .
Notice: When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or
equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid,
may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.
1. Inspect the brake fluid for the following conditions, indicating brake fluid contamination:
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Fluid separation, indicating 2 types of fluid are present; a substance other than the recommended brake fluid has been introduced into the brake
hydraulic system
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Swirled appearance - oil-based substance
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Layered appearance - silicone-based substance
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Fluid discoloration, indicating the presence of moisture or particles that have been introduced into the brake hydraulic system
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Cloudy appearance - moisture
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Dark appearance/suspended particles in fluid - dirt, rust, corrosion, brake dust
2. Inspect the master cylinder reservoir cap diaphragm and the reservoir-to-master cylinder grommets for swelling, indicating brake fluid
contamination.
3. If the brake fluid WAS contaminated with an oil-based or a silicone-based substance, indicated by fluid separation and/or a swollen master
cylinder reservoir cap diaphragm and/or swollen reservoir-to-master cylinder grommets, perform the following:
1. Remove ALL of the following components listed from the vehicle. Each component contains internal rubber seals/linings which have been
contaminated by the contaminated brake fluid in the brake hydraulic system.
Refer to the procedures indicated:
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Master Cylinder Replacement (See: Hydraulic System/Brake Master Cylinder/Service and Repair/Removal and Replacement/Master
Cylinder Replacement)
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Front Brake Hose Replacement (See: Hydraulic System/Brake Hose/Line/Service and Repair/Front Brake Hose Replacement)
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Rear Brake Hose Replacement (Caliper) (See: Hydraulic System/Brake Hose/Line/Service and Repair/Rear Brake Hose Replacement
(Caliper))Rear Brake Hose Replacement (Jounce) (See: Hydraulic System/Brake Hose/Line/Service and Repair/Rear Brake Hose
Replacement (Jounce))
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Front Brake Caliper Replacement (See: Disc Brake System/Brake Caliper/Service and Repair/Removal and Replacement/Front Brake
Caliper Replacement)
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Rear Brake Caliper Replacement (See: Disc Brake System/Brake Caliper/Service and Repair/Removal and Replacement/Rear Brake
Caliper Replacement)
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Brake Pressure Modulator Valve Replacement (w/JL4) (See: Antilock Brakes / Traction Control Systems/Hydraulic Control Assembly -
Antilock Brakes/Service and Repair/Brake Pressure Modulator Valve Replacement (W/JL4))Brake Pressure Modulator Valve
Replacement (w/o JL4) (See: Antilock Brakes / Traction Control Systems/Hydraulic Control Assembly - Antilock Brakes/Service and
Repair/Brake Pressure Modulator Valve Replacement (W/O JL4))
2. Clean out all the hydraulic brake pipes using denatured alcohol, or equivalent.
3. Dry the brake pipes using non-lubricated, filtered air.
4. Repair or replace ALL of the following components listed and install them to the vehicle. Each component contains internal rubber
seals/linings which have been contaminated by the contaminated brake fluid in the brake hydraulic system.
Refer to the procedures indicated:
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Master Cylinder Overhaul (See: Hydraulic System/Brake Master Cylinder/Service and Repair/Overhaul) or Master Cylinder Replacement
(See: Hydraulic System/Brake Master Cylinder/Service and Repair/Removal and Replacement/Master Cylinder Replacement) ; also
perform the following:
Clean the brake master cylinder reservoir using denatured alcohol, or equivalent, then dry the reservoir using non-lubricated, filtered air.
Inspect the reservoir for cracks and/or damage and replace if necessary. Refer to Master Cylinder Reservoir Replacement (See: Hydraulic
System/Brake Master Cylinder/Service and Repair/Removal and Replacement/Master Cylinder Reservoir Replacement) .
Replace the brake master cylinder reservoir cap diaphragm.
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Front Brake Hose Replacement (See: Hydraulic System/Brake Hose/Line/Service and Repair/Front Brake Hose Replacement)
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Rear Brake Hose Replacement (Caliper) (See: Hydraulic System/Brake Hose/Line/Service and Repair/Rear Brake Hose Replacement
(Caliper))Rear Brake Hose Replacement (Jounce) (See: Hydraulic System/Brake Hose/Line/Service and Repair/Rear Brake Hose
