Notice: Do not use fluid that has a petroleum base. Do not use a container that has been used for petroleum based fluids or is wet with water. Petroleum-based fluids cause swelling and distortion of rubber parts in the hydraulic brake system and water lowers the brake fluid's boiling point. Keep all fluid containers capped to prevent contamination.

Thoroughly clean the master cylinder reservoir cover before removal. This prevents dirt from entering the reservoirs.

1. Remove the cover and the diaphragm.
2. Add brake fluid in order to fill the reservoirs to the full mark. The full mark is typically located inside the reservoir. Use Delco Supreme 11® Hydraulic Brake Fluid GM P/N 12377967 or equivalent DOT 3 motor vehicle brake fluid.