Hydraulic System: Service and Repair
FLUSHING BRAKE HYDRAULIC SYSTEMIMPORTANT:
^ If evidence of contamination is present in the vehicle's brake fluid, flush the entire brake system following one of the following procedures.
^ Flush the system under the following
- If there is any doubt about the condition of the fluid in the system .
- If the fluid that is used contains the slightest trace of mineral oil (from such things as engine oil, transmission fluid, etc.)
^ After flushing the entire brake system, replace all rubber components.
^ Replace the following components:
- The brake hose assemblies
- The master cylinder rubber parts
- The brake caliper seals
- The brake modulator
- The brake solenoid valves
^ Refer to the appropriate replacement procedures.
^ After replacing all rubber components, re-flush the entire brake system by performing one of the following procedures.
^ After performing the second flushing procedure, perform a complete system bleed. Refer to Brake Bleeding.
CAUTION:
^ Use only SUPREME 11 (GM PN# J2377967) DOT 3 brake fluid from a clean, sealed container. Do not use fluid from an open container that may be contaminated with water. Improper or contaminated fluid could result in damage to components, or loss of braking, with possible injury.
^ Overfilling the reservoir must be avoided due to the potential for overflow onto the nearby catalytic converters in the exhaust system. Brake fluid is flammable, and contact with hot exhaust components could result in a fire and possible personal injury.
PRESSURE FLUSHING
^ TOOLS REQUIRED
- J 29532 Diaphragm Type Brake Bleeder
- J 35589 Compact Brake Bleeder Adapter
NOTICE: Pressure Bleeding equipment can be used to perform the flush procedure. The pressure bleeding equipment used for flushing must be of the diaphragm type. It must a have a rubber diaphragm between the air supply and the brake fluid to prevent air, moisture, and other contaminants from entering the hydraulic system.
1. Clean the brake fluid reservoir cover and the surrounding area.
2. Remove the brake fluid reservoir cover.
3. Remove any remaining brake fluid in the reservoir.
4. Refill the brake fluid reservoir with clean DOT 3 brake fluid to the proper level.
5. Install the J 35539 to the brake fluid reservoir.
6. Install the J 35589 to the pressure bleeding equipment.
7. Adjust the pressure bleeding equipment to 35-70 kPa (5-10 psi) and wait for approximately 30 seconds in order to ensure there is no leakage.
8. Adjust the pressure bleeding equipment to 205-240 kPa (30-35 psi).
9. Raise and suitably support the vehicle.
IMPORTANT: The following list indicates the wheel position flush sequence:
1. Right rear
2. Left rear
3. Right front
4. Left front
IMPORTANT: Ensure that the bleeder valves do not leak.
10. Use the following procedure in order to flush the brakes:
10.1. Attach the bleeder hose to the bleeder valve at each wheel.
10.2. Place the other end of the bleeder hose into a container in order to collect the draining brake fluid. Do not submerge the hose end in fluid.
10.3. Slowly open the bleeder valve and allow the fluid to flow.
10.4. Close the valve when clean brake fluid begins to flow or at least 235 ml (8 oz) of fluid accumulates.
^ Tighten the front caliper bleeder valves to 13 Nm (115 in. lbs.).
^ Tighten the rear caliper bleeder valves to 7 Nm (62 in. lbs.).
11. Lower the vehicle.
12. Remove the bleeder adapter.
13. Replace all the rubber components listed under Flushing Procedure.
14. Repeat the flushing procedure one more time.
15. inspect the brake fluid level in the reservoir. Fill the reservoir to the correct level if necessary.
16. Install the brake fluid reservoir cap.
17. Bleed the entire brake hydraulic system. Refer to Brake Bleeding.
MANUAL FLUSHING
IMPORTANT: Use a suitable container and/or shop rags in order to catch fluid and prevent the fluid from contacting any painted surfaces.
1. Clean the brake fluid reservoir cover and the surrounding area.
2. Remove the brake fluid reservoir cover.
3. Remove any remaining brake fluid in the brake fluid reservoir.
4. Refill the brake fluid reservoir with clean DOT 3 brake fluid to the proper level.
5. Install the brake fluid reservoir cover.
6. Raise and suitably support the vehicle.
IMPORTANT: The following list indicates the wheel position flush sequence:
1. Right rear
2. Left rear
3. Right front
4. Left front
IMPORTANT: Ensure that the bleeder valves do not leak.
7. Use the following procedure in order to flush the wheel brakes:
7.1. Attach the bleeder hose to the bleeder valve at each wheel.
7.2. Place the other end of the bleeder hose into a container in order to collect the draining brake fluid. Do not submerge the hose end in fluid.
7.3. Slowly open the bleeder valve and allow the fluid to flow.
7.4. Close the valve when clean brake fluid begins to flow or at least 235 ml (8 oz) of fluid accumulates.
^ Tighten the front caliper bleeder valves to 13 Nm (115 in. lbs.).
^ Tighten the rear caliper bleeder valves to 7 Nm (62 in. lbs.).
8. Lower the vehicle.
9. Replace all of the following rubber components:
^ The brake hose assemblies
^ The master cylinder rubber parts
^ The brake caliper seals
^ The brake modulator
^ The brake solenoid valves
10. Repeat this manual flushing procedure one more time.
11. Inspect the brake fluid level in the reservoir. Fill the reservoir to the correct level if necessary.
12. Replace the brake fluid reservoir cap.
13. Bleed the entire brake hydraulic system. Refer to Brake Bleeding.