Hydraulic System Flushing
WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
- 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, brake dust.
- 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):
- 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.
- See MASTER CYLINDER under REMOVAL & INSTALLATION.
- See FRONT BRAKE HOSE under REMOVAL & INSTALLATION.
- See REAR DISC BRAKE HOSE under REMOVAL & INSTALLATION.
- See FRONT BRAKE CALIPER under REMOVAL & INSTALLATION.
- See WHEEL CYLINDER under REMOVAL & INSTALLATION.
- Brake Pressure Modulator Valve (BPMV). See appropriate ANTI-LOCK article in BRAKES.
- 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.
- 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. See MASTER CYLINDER RESERVOIR under REMOVAL & INSTALLATION. Replace the brake master cylinder reservoir cap diaphragm.
- See FRONT BRAKE HOSE under REMOVAL & INSTALLATION.
- See REAR DISC BRAKE HOSE under REMOVAL & INSTALLATION.
- See FRONT BRAKE CALIPER under REMOVAL & INSTALLATION.
- See WHEEL CYLINDER under REMOVAL & INSTALLATION.
- Brake Pressure Modulator Valve (BPMV). See appropriate ANTI-LOCK article in BRAKES.
- 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.
- 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 Delco Supreme 11(R) (GM P/N 12377967) or equivalent DOT-3 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. See BLEEDING BRAKE SYSTEM .