2001 GMC Yukon XL 1500 Brake Master Cylinder

The proper way is to apply the parking brake, remove the master cylinder, drain the master cylinder reservoir, clamp the master cylinder to a bench vice, remove the roll pins securing the reservoir to the master cylinder, and grasp the reservoir.

The proper way is to secure the mounting flange of the brake master cylinder in a bench vise, remove the master cylinder reservoir cap and diaphragm, install suitable fittings to the master cylinder ports, and transparent hoses to the fittings installed to the master cylinder ports, fill the master cylinder reservoir to at least the half-way point with Delco Supreme 110 (GM P/N 12377967), ensure that the ends of the transparent hoses running into the master cylinder reservoir are fully submerged in the brake fluid, depress and release the primary piston as far as it will travel, continue to depress and release the primary piston, remove the transparent hoses from the master cylinder reservoir, install the master cylinder reservoir cap and diaphragm, and remove the fittings with the transparent hoses, and the master cylinder from the vise.

The proper way is to install the master cylinder reservoir, bench bleed the master cylinder, install the master cylinder and the master cylinder mounting nuts, connect the brake pipes and the electrical connection at the brake fluid level sensor, bleed the brakes, and release the parking brake.

The proper way is to remove the brake master cylinder, secure the mounting flange of the brake master cylinder in a bench vise, remove the reservoir cap and diaphragm and the master cylinder reservoir, and remove the piston retainer and the primary piston assembly, discard the primary piston assembly, the piston retainer, and the seals and seal retainer from the secondary piston.

The proper way is to visually inspect the brake fluid level through the brake master cylinder reservoir. If the brake fluid level is at or below the half-full point, the brake system should be inspected for wear and possible brake fluid leaks. If the brake fluid level is at or below the half-full point, and an inspection of the brake system did not reveal wear or brake fluid leaks, the brake fluid may be topped-off up to the maximum-fill level. If brake system service was just completed, the brake fluid may be topped-off up to the maximum-fill level. If the brake fluid level is above the half-full point, adding brake fluid is not recommended under normal conditions. If the brake fluid is to be added to the master cylinder reservoir, clean the outside of the reservoir on and around the reservoir cap before removing the cap and diaphragm.