GM Service Manual Online
For 1990-2009 cars only

Filling The Master Cylinder Reservoir


Object Number: 182425  Size: SH

Caution: Use only SUPREME 11 or equivalent DOT 3 brake fluid from a clean, sealed container. Do not use fluid from an open container that may be contaminated with water. Improper or contaminated fluid will result in damage to components or loss of braking, with possible personal injury.

Ensure that the master cylinder reservoir (2) is kept properly filled. An adequate reserve of brake fluid will prevent air from entering the brake hydraulic system. However, because heat absorbed from the brakes and the engine expands the brake fluid, do not overfill the reservoir.

A drop in the brake fluid level is normal as the pads wear. If the master cylinder reservoir is filled before new pads are installed, brake fluid may spill over once the new pads are in place. Unless there is a leak in the brake hydraulic system, or the brake hydraulic system has been serviced, do not top off the master cylinder reservoir.

Clean the master cylinder reservoir cap thoroughly before removal in order to avoid contaminating the reservoir. Remove the reservoir cap and the reservoir diaphragm.

Add brake fluid to the reservoir in order to bring the fluid level to the fill line. The fill line is located on the side of the reservoir.