OEM 2000 GMC Safari Brake Master Cylinder

2000 GMC Safari Brake Master Cylinder Parts Questions & Experts Answers

• Q: How should the brake master cylinder be overhauled to ensure proper function and avoid damage on 2000 GMC Safari?

  A: Brake Master Cylinder overhauls should include new cylinder body replacement instead of bore honing because the hard and polished surface gets damaged when honing occurs which results in premature rubber cup wear. The first step involves removing cover and diaphragm while draining the brake fluid from the reservoir. First disconnect the two locking pins and extract the reservoir assembly and its grommets from the master cylinder body. Use a vise to hold the master cylinder mounting flange while using a bar tool to separate the reservoir from its position. Pull out the snap ring while taking out the primary Piston assembly from the master cylinder body. When extracting the secondary Piston through air pressure place the open cylinder bore end 25 millimeters (1 inch) above a cushioned surface but apply air pressure at a low rate. Apply air pressure to the front port of the master cylinder after plugging the rear port then extract the spring retainer plus the seals and spring. Wash all metal components with denatured alcohol yet rubber components need clean brake fluid for cleaning purposes while checking for any potential contaminants. To check for diaphragm damage examine for cylinder bore scoring or corrosion (cylinder replacement required if corrosion is present) and inspect the reservoir for any sign of cracks. Lubricate the grommets and seals and cylinder bore by using new seals and clean brake fluid during assembly. Install the spring followed by spring retainer before placing the primary seal and secondary seal on the secondary Piston. Position both pistons with the snap ring into the master cylinder body space before fastening it while adjusting the primary Piston when necessary. Screw two fresh grommets onto the master cylinder before putting the reservoir into place then use a rocking motion to set it. To finish the installation you should piece together the reservoir locking pins along with diaphragm placement into the cover to lock the reservoir.