GMC's Sierra line of pickup trucks is one of the many popular models of GMC vehicles in the U.S. Attractive and tough, they have a great reputation for durability and reliability just like similar models offered by GMC's sister brand Chevrolet. As with any vehicle on the road today, the 2003 Sierra requires periodic maintenance to keep it operating at its best. Replacing worn brake pads is no exception.
Block the rear or front wheels with wheel chocks, depending on which set of brakes you will be working on first. The wheels which will not be worked on must stay on the ground and be blocked from moving.
Pull the cover off of the brake master cylinder located under the hood on the driver's side by hand and use a turkey baster to remove half of the fluid from the reservoir. Squirt the fluid into a jar and replace the cap on the master cylinder.
Use a lug wrench to loosen the wheel studs of the brakes to be serviced on both sides of the truck but do not remove the wheel studs, just loosen them. Place a floor jack under the vehicle and raise it up. Place a jack stand under a solid point on the truck, such as a frame rail, and gently lower the vehicle until it rests on the jack stand. Repeat for the other side.
Remove the nuts from the wheel studs and remove the wheels. Only work on one side of the vehicle at a time so that you can leave one set of brakes assembled for reference if needed.
Place a dripping pan underneath the brake assembly to be worked on and clean the brake surfaces with spray-on brake cleaner. Spray the assembly until the cleaner runs off into the drain pan.
Place a large C-clamp over the brake caliper and position it so the handle is on the outside of the assembly. Make sure the screw end of the clamp is seated against the brake pad on the outer side of the caliper. Slowly tighten the clamp to compress the brake caliper. Be sure to check the master cylinder for overflow and remove any fluid with the turkey baster if necessary. Remove the clamp when you can no longer compress the caliper.
Use a hex head wrench to loosen and remove the lower caliper mounting bolt located on the inside bottom of the caliper. Tilt the caliper up and away from the rotor if installing front brake pads. If replacing rear brake pads, use an open end wrench to hold the caliper slide pin that has the caliper bolt running through it in place located at the bottom of the caliper. Then use a box end wrench to loosen the caliper mounting bolt. Pivot the assembly up and away from the rotor.
Remove the brake pads by pulling them out of their mounts. Discard them.
Remove the upper and lower retainers from the pad mounts, making sure to note their positions and inspect them for damage. If they are undamaged, they can be reused. If they are damaged, they must be replaced.
Apply anti-squeal compound to the backs of the new brake pads and allow it to firm up for a few minutes. Reinstall the upper and lower pad retainers by sliding them into their positions on the mounts. Refer to the still assembled brakes, if necessary, to determine their positioning.
Press the inner brake pad in by hand and do the same with the outer pad. Again, refer to the assembled brakes if unsure about their positioning. Slide the brake caliper down and into place over the installed brake pads.
Begin securing the caliper onto the front brakes by lubricating the lower caliper bolt with brake grease and inserting it into the caliper, being careful to avoid getting grease onto the brake assembly. Tighten the bolt firmly with the hex head wrench. On rear brakes, lubricate the slide pin and insert it into the caliper without getting grease on the brake assembly. Insert the caliper bolt into the slide pin and tighten the bolt firmly with a box end wrench.
Repeat Steps 5 through 12 for the other side of the truck.
Replace both wheels onto the vehicle, and reinstall and tighten the lug nuts by hand as tight as possible. Lower the truck off of the jack stands and tighten the lug nuts using the lug wrench.
Check the brake fluid in the master cylinder and top it off with fresh brake fluid if necessary.
Use caution when working with brake fluid. Brake fluid can damage paint and ruin finishes.
Use caution when working with brake fluid. Brake fluid can damage paint and ruin the finish. Do not use compressed air to blow brake dust off of brake assemblies. Brake dust contains asbestos and can be harmful if inhaled.