GM 22707256 Power Brake Booster Assembly

To perform an operating check on the brake system, start by depressing the brake pedal multiple times with the engine off to ensure there is no change in the pedal reserve distance. Then, depress the pedal and start the engine, checking for a slight downward movement of the pedal, which indicates normal operation. For an airtightness check, start the engine and turn it off after a minute or two. Slowly depress the brake pedal several times, noting if it goes down further on the first depression but gradually rises on subsequent depressions, indicating an airtight booster. To install the booster, place it into position and tighten the retaining bolts to the specified torque. Connect the pushrod to the brake pedal and install the clip. Install the master cylinder and reconnect the vacuum hose. For ABS-equipped models, reposition the hydraulic control unit and secure it with mounting nuts.

Brakes should be checked whenever the wheels have been changed or if there are signs of a problem and the signs are pulling to one side, squealing or dragging noises, ability to travel a long distance, pulsating of the pedals or brake fluid leakage. For disc brakes visually inspect in place without having to dismantle by loosening the wheel lug nuts, raising the car safely and removing the wheels in order to get access to the caliper and the pads. Take the outer pad thickness, take the inner pad thickness, replace all the pads if any is lower than the set limit. This is another good indicator, which should be checked for score marks or wear before refitting brake lines and hoses as well as wheels. As for rear drum brakes, check that the parking brake is switched off, tap on a drum before removing them for cleaning. Check the thickness of the lining of the brake shoes and if they are below the limit or if they are damaged get a new one. Check all springs if they're appropriately linked together and look for signs of any loss of lubricant especially in wheel cylinder. Clean the interior of the drum and check for damage and cracks, if any, and refinish the same if required. To do the brake booster check, press the brake while cranking the engine and look if the pedal goes down, check again pedal travel with the engine running and after turning it off. If the pedal is not giving the expected reaction then the brake booster can be defected.