Hydraulic Brakes
Warning: Brake fluid may irritate eyes and skin. In case of contact, take the following actions:
• Eye contact--rinse thoroughly with water. • Skin contact--wash with soap and water. • If ingested--consult a physician immediately.
Caution: Refer to Brake Fluid Damage to Electrical Connections Caution in the Preface section.
Use Delco Supreme 11® Brake Fluid GM P/N 12377967 or the equivalent DOT-3 motor vehicle brake fluid. Do not use DOT-5 fluid in the brake system.
Store the brake fluid in a closed container. Always use new brake fluid from a sealed container. Tightly close the brake fluid container immediately after use. Brake fluid stored in an open or an improperly sealed container will absorb moisture. Brake fluid stored in an open or an improperly sealed container will lower the fluid boiling point and result in system contamination, corrosion or the deterioration of the rubber components.
Substandard or Contaminated Brake Fluid
Caution: Power steering fluid and brake fluid cannot be mixed. If brake seals contact power steering fluid or steering seals contact brake fluid, seal damage will result.
Ensure the use of the correct fluids. The master cylinder and the brake system use brake fluid. The hydraulic booster uses power steering fluid.
The following substances cause the brake fluid to boil or deteriorate the rubber components in the hydraulic system:
| • | Improper fluids |
| • | Mineral oil |
| • | Water |
| • | Other contaminants |
Swollen master cylinder piston seals indicate rubber deterioration. Deterioration is also indicated by swollen wheel cylinder boots, caliper boots or the master cylinder reservoir diaphragm.
Disassemble the brake hydraulic components and wash the components with alcohol if rubber deterioration is detected. Dry the hydraulic brake components with unlubricated compressed air before assembling in order to keep alcohol out of the system. Replace all of the rubber components in the system including the hoses. Inspect for fluid on the brake linings. Replace the brake linings if any fluid is detected.
Inspect the hydraulic brake system for leaks or excessive heat conditions if the brake fluid is contaminated and the master cylinder piston seals are satisfactory. Do the following procedures if leaks or excessive heat conditions are detected:
- Drain the system.
- Flush the system. Refer to Hydraulic Brake System Flushing.
- Refill the system.
- Bleed the system. Refer to Hydraulic Brake System Bleeding.
