Notice: When filling the master cylinder, use only Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT 3 brake fluid. Do not use a container which has been used for petroleum based fluids, or a container which is wet with water. Petroleum based fluids will cause swelling and distortion of rubber parts in the hydraulic brake system, and water will mix with brake fluid, lowering the boiling point. Keep all fluid containers capped to prevent contamination.

Keep the master cylinder brake fluid reservoir properly filled to ensure an adequate reserve and to prevent air and moisture from entering the hydraulic system. However adding brake fluid is not usually necessary unless the brake system has a leak, indicated by the BRAKE warning lamp coming on due to low brake fluid, or the system is being serviced. Because of the fluid expansion due to heat absorbed from the brakes and the engine the reservoir must not be overfilled.

The brake fluid level will become lower with brake lining wear and should return to approximately the full level when new linings are installed. If brake fluid has been added to the reservoir prior to the lining change, the resultant level may be over full.

To top up or fill the reservoir, thoroughly clean around the reservoir cap before removing it to avoid getting dirt into the reservoir. Remove the cap with the diaphragm. Add fluid as needed to bring the level to the full mark. Use only Delco® Supreme II Brake Fluid or an equivalent DOT 3 brake fluid.