2009 GMC Envoy Steering Shaft

Disable the Parking Brake Cable adjuster, and raise and support the vehicle.

Place the ignition switch in the OFF position, apply and release the brake pedal several times until the pedal becomes firm to deplete the power vacuum Brake Booster vacuum reserve, disconnect the power brake booster vacuum sensor electrical connector, and remove the power brake booster vacuum sensor.

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 also provide for hose attachment, and install transparent hoses to the fittings installed to the master cylinder ports, then route the hoses into the master cylinder reservoir, fill the master cylinder reservoir to at least the half-way point with GM approved brake fluid from a clean, sealed brake fluid container, release the primary piston as far as it will travel, a depth of about 25 mm (1 in), several times, continue to depress and release the primary piston until fluid flows freely from the ports with no evidence of air bubbles, remove the transparent hoses from the master cylinder reservoir, install the master cylinder reservoir cap and diaphragm, remove the fittings with the transparent hoses from the master cylinder ports, and remove the master cylinder from the vise.