Cruze

Hydraulic Brake System Flushing

Caution: When adding fluid to the brake fluid reservoir or to the clutch fluid reservoir, use only DOT-4+ brake fluid from a clean, sealed container. This polyglycol brake fluid is hygroscopic and absorbs moisture. Do not use fluid from an open container that may be contaminated with water. Improper or contaminated fluid could result in damage to the system components.

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

•	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:

--	Swirled appearance -- oil-based substance

--	Layered appearance -- silicone-based substance

•	Fluid discolouration, 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, 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:

3.1.	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:

•	Master Cylinder Replacement : Right Hand Drive → Left Hand Drive

•	Front Brake Hose Replacement

•	Rear Brake Hose Replacement : Disc Brake

•	Front Brake Calliper Replacement

•	Rear Brake Calliper Replacement : with Dampener → without Dampener

•	Brake Pressure Modulator Valve Replacement

•	Hydraulic Brake System Bleeding

3.2.	Clean out all the hydraulic brake pipes using methylated spirit, or equivalent.

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

3.4.	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 : Right Hand Drive → Left Hand Drive ; also perform the following:

•	Clean the brake master cylinder reservoir using methylated spirit, 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.

•	Front Brake Hose Replacement

•	Rear Brake Hose Replacement : Disc Brake

•	Front Brake Calliper Overhaul or Front Brake Calliper Replacement

•	Rear Brake Calliper Replacement : with Dampener → without Dampener

4. 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. The diaphragm may have allowed the moisture or particles to enter the hydraulic system.
5. Fill the brake master cylinder reservoir to the maximum-fill level with GM recommended brake fluid. Refer to Adhesives, Fluids, Lubricants, and Sealers for the recommended brake fluid.
6. 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 .