Chevrolet rear brakes use hydraulic calipers and friction pads, on most late models, that can deteriorate. The pads are a semi-metallic or ceramic material designed to thin over time, requiring replacement. The average backyard mechanic can replace the rear pads on a Chevrolet in about an hour.
Preparation
Raise the vehicle onto jack stands with a floor jack, then remove both rear wheels by turning their lug nuts counterclockwise. Set the wheels away from the vehicle.
Removal
Turn the drum's keeper bolt (in the center or slightly off-center of the drum housing, near the hub) counterclockwise, then pull the drum away from the brake assembly. The shoes are on either side, held in place with two long springs and one primary spring bolt in the center of each shoe. Using a screwdriver for leverage, remove the long spring hooks from the shoes' hooks. Turn the primary spring bolt counterclockwise, and pull the shoe straight out and away from the brake. Check the wheel cylinder, usually on the top of the brake, for leaking or damage.
Replacement
Replace the shoes with fresh units by pressing each shoe into the brake housing, then reattaching the primary spring bolt in a clockwise direction. Reconnect each long spring hook to the relative shoe hook with the screwdriver. Press the drum over the shoes and back onto the brake, lining up the keeper bolt hole. Secure the drum to the brake by turning the keeper bolt clockwise until snug. Replace the wheels and tighten the lug nuts in a clockwise direction, with an alternating pattern. Lower the vehicle from the jack stands with the floor jack, then test the brakes.