The rear braking system on the GMC pickup truck consists of several springs, a wheel cylinder and a pair of brake shoes. The front brake shoe on the wheel is the primary, while the one in the back is called the secondary. The secondary brake shoe is what serves as the parking brake. When the brakes begin to get thin, you need to replace them before they become thin enough to cause damage to the brake drums. It will take about an hour to replace the brakes on each wheel.
Instructions
- 1
Park the truck on a level surface and turn off the key. Do not set the parking brake. Place a set of wheel chocks in front of the front wheels of the GMC. Raise the rear end of the truck on the side you are starting with using the automobile jack. Place a jack stand under the GMC near the jacking point and raise it to the frame. Remove the lug nuts with the lug wrench and take the wheel off the truck.
2Pull the brake drum from the wheel assembly and examine it for damage. If the drum is cracked, scored or has other damage you will need to have it machined smooth, or replace it with a new one. If the drum is difficult to remove, back off the brake adjuster by turning the adjusting wheel at the back of the wheel assembly with a brake tool. If it is still difficult, try hitting the side of the drum with the rubber mallet several times until it breaks free.
3Remove the shoe return springs using the brake tool. Remove the shoe guide from the backing plate. Remove the brake shoe hold-down springs by gripping them with the pliers and pushing them in while turning them one-quarter of a turn. Remove the adjuster actuator by unhooking it and pulling it off. Remove the actuator adjuster spring and link. Remove the parking brake strut and strut spring by unhooking it and pulling it off.
4Remove the brake shoes from the backing plate by carefully pulling them away. Take care since the springs will have some pressure on the brake shoes. Allow the shoes to go together slowly and it will make it easier to unhook and remove the adjuster spring and adjuster. Disconnect the parking brake actuator from the secondary brake shoe. Discard the old brake shoes.
5Apply a light coat of brake grease to the brake adjuster and then twist it all the way shut. Connect the parking brake actuator to the new secondary shoe. Connect the springs to the brake shoes and then place the self-adjuster between them in the notches. Place the brake shoes on the backing plate and secure them by gripping the retainer springs with the pliers and pushing them while turning the spring one-quarter of a turn until they lock into place.
6Install the parking brake strut and strut spring. Install the actuator adjuster spring and link. Install the adjuster actuator by hooking it into place. Install the brake shoe guide and then connect the return springs using the brake tool. Place the brake drum on the wheel assembly. Install the tire and tighten the lug nuts with the lug wrench. Remove the jack stand from under the GMC and lower the truck to the ground. Repeat the procedure on the other wheel.
