Cobalt L4-2.2L (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 .
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 (Manual) (See: Brakes and Traction Control/Hydraulic System/Brake Master Cylinder/Service and
Repair/Removal and Replacement/Master Cylinder Replacement (Manual))Master Cylinder Replacement (Automatic) (See: Brakes and
Traction Control/Hydraulic System/Brake Master Cylinder/Service and Repair/Removal and Replacement/Master Cylinder Replacement
(Automatic))
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Front Brake Hose Replacement (Without RPO LNF) (See: Brakes and Traction Control/Hydraulic System/Brake Hose/Line/Service and
Repair/Front Brake Hose Replacement)Front Brake Hose Replacement (With RPO LNF) (See: Brakes and Traction Control/Hydraulic
System/Brake Hose/Line/Service and Repair/Front Brake Hose Replacement)
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Rear Brake Hose Replacement (Jounce) (See: Brakes and Traction Control/Hydraulic System/Brake Hose/Line/Service and Repair/Rear
Brake Hose Replacement (Jounce))Rear Brake Hose Replacement (Caliper) (See: Brakes and Traction Control/Hydraulic System/Brake
Hose/Line/Service and Repair/Rear Brake Hose Replacement (Caliper))
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Front Brake Caliper Replacement (Without RPO LNF) (See: Brakes and Traction Control/Disc Brake System/Brake Caliper/Service and
Repair/Removal and Replacement/Front Brake Caliper Replacement)Front Brake Caliper Replacement (With RPO LNF) (See: Brakes and
Traction Control/Disc Brake System/Brake Caliper/Service and Repair/Removal and Replacement/Front Brake Caliper Replacement)
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Rear Brake Caliper Replacement (See: Brakes and Traction Control/Disc Brake System/Brake Caliper/Service and Repair/Removal and
Replacement/Rear Brake Caliper Replacement) , if equipped
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Wheel Cylinder Replacement (See: Brakes and Traction Control/Drum Brake System/Wheel Cylinder/Service and Repair) , if equipped
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Proportioning Valve Replacement (See: Brakes and Traction Control/Hydraulic System/Brake Proportioning/Combination Valve/Service
and Repair) , if equipped
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Brake Pressure Modulator Valve Replacement (Without JL4) (See: Brakes and Traction Control/Antilock Brakes / Traction Control
Systems/Hydraulic Control Assembly - Antilock Brakes/Service and Repair/Brake Pressure Modulator Valve Replacement (Without JL4)
)Brake Pressure Modulator Valve Replacement (With JL4) (See: Brakes and Traction Control/Antilock Brakes / Traction Control
Systems/Hydraulic Control Assembly - Antilock Brakes/Service and Repair/Brake Pressure Modulator Valve Replacement (With JL4)) , if
equipped
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:
*
Master Cylinder Replacement (Manual) (See: Brakes and Traction Control/Hydraulic System/Brake Master Cylinder/Service and
Repair/Removal and Replacement/Master Cylinder Replacement (Manual))Master Cylinder Replacement (Automatic) (See: Brakes and
Traction Control/Hydraulic System/Brake Master Cylinder/Service and Repair/Removal and Replacement/Master Cylinder Replacement
(Automatic)) ; also perform the following:
Clean the brake master cylinder reservoir using denatured alcohol, or equivalent, then dry the reservoir using non-lubricated, filtered air.
