Yukon XL 4WD V8-5.3L (2011)
Brake Bleeding: Service and Repair
Hydraulic Brake System Flushing
Hydraulic Brake System Flushing
Warning: Refer to Brake Fluid Irritant Warning See: Service Precautions/Technician Safety Information/Brake Fluid Irritant Warning.
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution See: Service Precautions/Vehicle Damage Warnings/Brake Fluid
Effects on Paint and Electrical Components Caution.
Caution: 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 two 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 as applicable:
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Master Cylinder Replacement
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Front Brake Hose Replacement
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Rear Brake Hose Replacement
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Front Brake Caliper Replacement
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Rear Brake Caliper Replacement
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Brake Pressure Modulator Valve Replacement Two-mode Hybrid
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Brake Pressure Modulator Valve Replacement See: Hydraulic Control Assembly - Antilock Brakes/Service and Repair/Non-Hybrid Less
than 3900 kg (8600 lb) GVWNon-Hybrid Less than 3900 kg (8600 lb) GVW
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Brake Pressure Modulator Valve Replacement See: Hydraulic Control Assembly - Antilock Brakes/Service and Repair/Non-Hybrid
Greater than/Equal to 3900 kg (8600 lb) GVWNon-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
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 as applicable:
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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 .
Replace the brake master cylinder reservoir cap diaphragm.
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Front Brake Hose Replacement
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Rear Brake Hose Replacement
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Front Brake Caliper Overhaul See: Brake Caliper/Service and Repair/Overhaul/Front Brake Caliper Overhaulor Front Brake Caliper
Replacement
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Rear Brake Caliper Overhaul See: Brake Caliper/Service and Repair/Overhaul/Rear Brake Caliper Overhaulor Rear Brake Caliper
Replacement
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Brake Pressure Modulator Valve Replacement Two-mode Hybrid
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Brake Pressure Modulator Valve Replacement See: Hydraulic Control Assembly - Antilock Brakes/Service and Repair/Non-Hybrid Less
than 3900 kg (8600 lb) GVWNon-Hybrid Less than 3900 kg (8600 lb) GVW
