GM 88967235
Brake Booster

Begin Brake Booster replacement by protecting yourself using a negative Battery Cable disconnect and blocking the front wheels while applying the parking brake. Remove the power steering inlet hose together with the pressure hose and the power steering gear to booster hose. The booster assembly requires removal of its master cylinder together with the wiring harness bracket along with the spacer component. Remove the left closeout insulator panel with both the left knee bolster and knee bolster bracket. Before proceeding with the Brake Booster vacuum removal you must first disconnect and take out the vacuum Brake Booster retainer clip and foam spacer that secure the Brake Pedal clevis pin and then separate the vacuum Brake Booster push rod from the clevis pin before fully removing the vacuum Brake Booster assembly by taking off its mounting nuts . You should consider replacing the vacuum Brake Booster mounting gasket only when needed. Installation begins with mounting the booster gasket to its place followed by attaching the vacuum Brake Booster assembly while tightening the stud mounting nuts of the Brake Pedal assembly to 36 nm torque. Apply gm p/n 12346293 lubricant or equivalent on the Brake Pedal clevis pin. Then couple the pushrod of the vacuum Brake Booster to the Brake Pedal assembly clevis pin before installing both spacer foam and retaining clip. The installation order is left knee bolster bracket followed by left knee bolster then left closeout insulator panel. The sequence continues with the booster spacer along with the wiring harness bracket. After integrating the master cylinder with the booster assembly you should install the power steering pressure hose and power steering gear to booster hose and power steering inlet hose. To finish, put back the negative Battery Cable while performing a hydraulic booster system bleed followed by wheel block and parking brake release procedures.

The brake system requires pressure removal before replacement by performing at least 8 successive Brake Pedal pumps until pressure builds up completely. After draining brake fluid from the hydraulic Brake Booster reservoir the mechanic should proceed to disconnect the master cylinder fluid level sensor electrical connector. Pull the master cylinder forward by unstowing the mounting nut while taking caution to prevent brake pipes from damage during the process. The procedure begins by removing the hydraulic pressure (feed) line from behind the booster and continuing with hose clamp removal from the top of the booster that leads to the return hose before capping the open hydraulic lines to stop fluid loss and contamination. Begin by removing the right closeout panel then unfasten the Brake Pedal assembly mounting nuts of the hydraulic Brake Booster followed by removing both the pushrod retainer clip and the foam spacer from the Brake Pedal clevis pin. After you have detached the pushrod from its clevis pin you can remove the hydraulic Brake Booster out of the vehicle. The hydraulic Brake Booster needs to be positioned inside the vehicle and the pushrod must be connected to the Brake Pedal clevis pin and then the foam spacer and pushrod retainer clip must be installed. Fasten the hydraulic Brake Booster mounting nuts to its studs with a torque of 28 nm (21 ft. Lbs.). Begin by attaching the right closeout panel after which you should hook up the return hose together with its clamp to the hydraulic Brake Booster. Fasten the mount of the master cylinder to the booster unit before connecting its hydraulic pressure line and tightening the mounting nuts to 27 nm (20 ft. Lbs.). Refill the booster reservoir then connect the fluid level sensor electrical connector before bleeding the brake system if the hydraulic system had been opened.

Replace the vacuum brake booster mounting gasket if necessary.

Reconnect the power steering pressure hose, power steering gear to booster hose, and power steering inlet hose.

Remove the master cylinder and the wiring harness bracket.

If necessary, replace the vacuum brake booster mounting gasket.

If necessary, replace the vacuum brake booster mounting gasket.

Secure the booster with the attaching nuts (1,2,3) and tighten them to 32 Nm (24 ft. lbs.).

Install the foam spacer and retaining clip, then reinstall the left knee bolster and left closeout insulator panel, followed by the booster spacer and wiring harness bracket.

Install the booster back into the vehicle and attach the pushrod to the brake pedal, tilting the booster slightly to avoid side pressure.

Remove the surge tank mounting screw and nuts, then position the surge tank out of the way.

Remove the brake fluid from the hydraulic brake booster reservoir and disconnect the master cylinder fluid level sensor electrical connector.

Reconnect the power steering pressure hose, power steering gear to booster hose, and power steering inlet hose, reconnect the negative battery cable, bleed the hydraulic booster system, remove the blocks from the front wheels, and release the parking brake.