Chevrolet Sonic Repair Manual: Hydraulic Brake System Flushing

Chevrolet Sonic Repair Manual / Chassis / Brakes / Hydraulic Brakes / Hydraulic Brake System Flushing

Warning:

Refer to Brake Fluid Irritant Warning.

Caution:

Refer to Brake Fluid Effects on Paint and Electrical Components Caution.

Inspect the brake fluid for the following conditions, indicating brake fluid contamination:

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.

Swirled appearance – oil-based substance
Layered appearance – silicone-based substance

Fluid discoloration, indicating the presence of moisture or particles that have been introduced into the brake hydraulic system.

Cloudy appearance – moisture
Dark appearance/suspended particles in fluid – dirt, rust, corrosion and/or brake dust

Inspect the master cylinder reservoir cap diaphragm and the reservoir-to-master cylinder grommets for swelling, indicating brake fluid contamination.

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:

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:

Master Cylinder Replacement
Front Brake Hose Replacement
Rear Brake Hose Replacement
Front Brake Caliper Replacement
Rear Brake Cylinder Replacement
Brake Pressure Modulator Valve Replacement

Clean out all the hydraulic brake pipes using denatured alcohol, or equivalent.

Dry the brake pipes using non-lubricated, filtered air.

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; 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.
Front Brake Hose Replacement
Rear Brake Hose Replacement
Front Brake Caliper Replacement
Rear Brake Cylinder Replacement
Brake Pressure Modulator Valve Replacement

If the brake fluid WAS NOT contaminated with an oil-based or a silicone-based substance, but WAS contaminated with water or dirt, rust, corrosion, and/or brake dust, replace the brake master cylinder reservoir cap diaphragm which may have allowed the moisture or particles to enter the hydraulic system.

Fill the brake master cylinder reservoir to the maximum-fill level with the approved brake fluid from a clean, sealed brake fluid container.

Pressure bleed the hydraulic brake system. Begin the procedure with the pressure bleeder reservoir filled to the maximum-fill level with the correct brake fluid as indicated. Refer to Hydraulic Brake System Bleeding.

Hydraulic Brake System Description and Operation

System Component Description The hydraulic brake system consists of the following: Hydraulic Brake Master Cylinder Reservoir Contains a supply of brake fluid for the hydraulic br ...

Master Cylinder Reservoir Filling

Warning: Refer to Brake Fluid Irritant Warning. Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution. Visually inspect the brake fluid level through the ...

Other materials:

Certification Label
Label Example A vehicle-specific Certification label is attached to the vehicle's center pillar (B-pillar). The label tells the gross weight capacity of the vehicle, called the Gross Vehicle Weight Rating (GVWR). The GVWR includes the weight of the vehicle, all occupants, fuel, and carg ...

Brake Assist
This vehicle has a brake assist feature designed to assist the driver in stopping or decreasing vehicle speed in emergency driving conditions. This feature automatically uses the stability system hydraulic brake control module to supplement the power brake system under conditions where the dri ...

Crankshaft Balancer Replacement
Special Tools EN-470–B Angular Torque Wrench EN-49979 Crankshaft Shock Mount Retainer For equivalent regional tools, refer to Special Tools. Removal Procedure Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle. Remove front wheelhouse liner exten ...

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