GM 15234621
Brake Booster

Before replacing the vacuum Brake Booster start by reducing fuel line pressure and draining the cooling system. Take the Coolant Reservoir left front cross brace and powertrain control module (PCM) cover off from their position on the air cleaner housing. Without disconnecting its power source put the pcm aside and take out the air cleaner and duct together. Disconnect both fuel lines from the pipes and vapor line before moving the heater hose off the crossover pipe. You can access the brake pipes better by unclipping the fuel lines from their shock tower position before disconnecting the brake fluid level sensor switch from the master cylinder and taking out both lines plus the master cylinder. Pull out the abs module and bracket from their position while disconnecting the Brake Booster Vacuum Hose from the vacuum Brake Booster check valve and setting it aside. Remove the knee bolster first. Then detach and pull out the Brake Booster push pin clip along with washer from the Brake Pedal assembly. Complete the process by removing the push rod from the booster. Move the engine forward by disengaging its front engine mounts and Brake Booster mounting nuts to reach and remove the Brake Booster. Locate the Brake Booster on top of the cowl and mounting plate before tightening its nuts to 25 nm (18 ft. Lbs.). Place the master cylinder into position and insert the Brake Booster push rod into the Brake Pedal. Attach it with the washer and retaining clip. Set up the Brake Pedal sensor after adjusting the stoplamp connector for correct operation and fix the knee bolster. Put the engine back in its original place and bolt on the engine mounts including their nuts. Put back the Brake Booster Vacuum Hose to its valve before installing the abs unit holder and hardware while placing the brake lines into the master cylinder. Fasten the master cylinder fluid level sensor before positioning the fuel pipes for the shock tower and linking the heater hose to the coolant crossover pipe. Place the air cleaner and duct back into the engine bay while installing both the pcm and its cover. After that put in the left front cross brace and Coolant Reservoir. Complete the fluid procedures by filling the cooling system and pumping out air from the brake lines.

You must release fuel line pressure first with ch 48027 or do so without tools and drain the cooling system by using either static fill lz9 or vac-n-fill. Uninstall the coolant recovery reservoir on one side and both the pontiac/chevrolet left front cross brace and the ecm cover from the air cleaner assembly. Place the ecm to the side without unplugging its power cable and then extract the air filter assembly. Disconnect all fuel lines from their connections to pipes and vapor line before placing the heater hose back to its position on the coolant crossover pipe. To work on the brake pipes properly detach them from the shock tower line access and then disconnect the brake fluid level sensor switch and remove the brake lines and master cylinder. To begin detach the Brake Booster Vacuum Hose from the check valve then remove the brake pressure modulator valve (BPMV) assembly together with its bracket. First step to change the Brake Booster is taking out the knee bolster and Brake Booster push rod's mounting nuts while removing the Brake Booster push pin retaining clip and washer from the Brake Pedal assembly. Pull the engine forward to reach the Brake Booster and detach it from its position. Place the new booster at the mounting plate and cowl position and thread in the mounting nuts before tightening them to 18 lb ft (25 N.m). Fit the master cylinder and place the Brake Booster push rod into the Brake Pedal before putting the retaining clip and washer. Reposition the engine to reconnect the knee bolster after setting the Brake Pedal position sensor. Reattach the Brake Booster Vacuum Hose and put on the bpmv assembly together with its bracket. Then link the brake tubes to the master cylinder and put the fluid level sensor switch in place. Install all the fuel lines to the shock tower with the heater hose link to the coolant crossover pipe followed by the air filter system and components such as the ecm under its cover. At last replace the left front cross brace and coolant recovery reservoir then refill and bleed the cooling system before completing the hydraulic brake system.

Install the master cylinder and then the brake booster push rod to the brake pedal, securing it with the washer and retaining clip.

Fill and bleed the cooling system, and bleed the brake system.