Substandard or Contaminated Brake Fluid

Important:

• Use only Delco Supreme 11® Brake Fluid, GM P/N 1052535 (Canadian P/N 992667), 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 .