GM Service Manual Online
For 1990-2009 cars only

Brake Fluid and Brake Fluid Handling Brake Fluid

Caution: 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.

Notice: Brake fluid is extremely damaging to paint. If fluid should accidentally touch a painted surface, immediately wipe fluid from paint and clean the painted surface.

Use Delco Supreme II Brake Fluid (GM P/N 12377967) or an equivalent DOT-3 motor vehicle brake fluid. DOT-5 silicone fluid is not recommended for use in the vehicle's base brake system. DO NOT use DOT-5 brake fluid in the antilock brake system.

Always store the brake fluid in a closed container. Reseal brake fluid containers immediately after use.

Brake fluid that is left in an open or improperly sealed container will absorb moisture. This may lower the fluid's boiling point and may result in system contamination, corrosion or deterioration of the rubber components.

Brake Fluid and Brake Fluid Handling Substandard Brake Fluid

Notice: Use only DOT 3 brake fluid from a clean, sealed container. Do not use any fluid from a container which is wet with water. Do not use DOT 5 silicone brake fluid. Improper brake fluid, mineral oil or water in the fluid may cause the brake fluid to boil or the rubber components to deteriorate. Keep all fluid containers capped to prevent contamination.

Important: Improper brake fluid such as, mineral oil or water in the fluid, may cause the brake fluid to boil or the rubber components in the hydraulic system to deteriorate.

Upon inspection, if the primary piston cups are swollen, then rubber parts have deteriorated. This deterioration may also be evidenced by the swollen wheel cylinder piston cups on the drum brake wheel cylinders or the master cylinder cover diaphragm.

If deterioration of rubber parts is evident disassemble all hydraulic parts and was with alcohol. Dry these parts with unlubricated compressed air before assembly to keep alcohol out of the system. Replace all rubber parts when in the system, including hoses. Also, when working on the brake mechanisms, check for fluid on the brake linings. If any fluid is found, replace the linings.

If the master cylinder piston seals are satisfactory, check for leakage or excessive heat conditions. If excessive heat conditions are not found, drain the fluid. Flush, the system with brake fluid. Refill and bleed the system.