Brake Fluid: Description and Operation

Brake Fluid and Brake Fluid Handling
Substandard or Contaminated Brake Fluid

Important:
^ Use only Delco Supreme 11 Brake Fluid, GM P/N 1052535, or equivalent DOT 3 fluid.
^ Do not use power steering or transaxle fluid in the brake system.
^ Do not reuse brake fluid collected during system bleeding.
^ Always store brake fluid in a closed container.
^ Reseal brake fluid containers immediately after use.
^ Do not use brake fluid left in an open container or an improperly sealed container because it absorbs moisture or can become contaminated.
^ The following fluids may cause the brake fluid to boil or the rubber components in the hydraulic system to deteriorate:
- Water
- A silicone based fluid
- A petroleum based fluid
- Mineral oil
^ The following conditions provide evidence that the rubber components have deteriorated:
- Swollen primary piston cups
- Swollen piston cups on the drum brake wheel cylinders
- Substandard or contaminated brake diaphragm
- Substandard or contaminated master cylinder cover diaphragm
^ If deterioration of rubber is evident, complete the following procedure:
1. Disassemble all of the hydraulic parts.
2. Wash all of the parts with alcohol.
3. Dry these parts with non-lubricated compressed air before assembly in order to keep alcohol out of the system.
^ Replace all of the rubber parts in the system, including the hoses.
^ Inspect the brake linings for fluid. If excessive fluid is found on the brake linings, replace the brake linings.
^ If the master cylinder piston seals are satisfactory, inspect for the following conditions:
- Leaking
- Excessive heat
^ If these conditions are not found, flush the hydraulic brake system. Refer to Hydraulic Brake System Flushing.