GM 20800046
Brake Booster

Start replacement of the power vacuum Brake Booster (LHD) by removing the left side instrument panel insulator panel. Remove the vacuum Brake Booster Pushrod retaining clip first before disconnecting the Pushrod from the brake pedal pivot. To start the job remove the Pushrod bushing and wave washer before removing the cross vehicle brace if it exists. Loosen the master cylinder nuts without separating the brake lines before detaching the sensor connector and moving the master cylinder aside on heavy mechanics wire. Take the radiator surge tank only out of its position while keeping the hoses connected. Take off the vacuum Brake Booster check valve and its connected hose. Adjust the j-22805-b Brake Booster holder by stretching its mounting holes and cutting 6.36mm (0.25in) from the inside edge until the span measures 80.00mm (3.15in). Fit and tighten the modified j-22805-b onto the vacuum Brake Booster by fixing it onto master cylinder nuts. Use a flat blade tool to push down on the locking tab and turn the holder and vacuum booster counterclockwise to take it off its bracket. Guide the vacuum booster forward to reach and disconnect the Pushrod retaining clip. Take out the Pushrod from its booster then remove the vacuum booster from the vehicle. Put the Pushrod back through the dust boot from inside the vehicle if needed. Place the booster pieces back together and install it into position when the inner parts and flange locking mechanisms have no damage. Put the vacuum booster in its final position then attach the Pushrod through the retaining clip. Move the booster reliably forward and watch for the locking tab to contact and hold the cowl flange before taking out the holder and throwing away the master cylinder nuts. Fit the vacuum Brake Booster check valve and hose before joining the master cylinder to the booster while tightening new nuts to 25 nm (18 lb ft). Put back the master cylinder fluid sensor and place all parts back in their original positions including the cross vehicle brace when needed. Seal the Pushrod with a wave washer before placing its bushing then mount the attachment point to the brake pedal followed by the retaining clip installation. Reposition the instrument panel insulator panel on the left side while testing the brake pedal sensor function.

Position the master cylinder aside with heavy mechanics wire.