Today, nearly all automobiles use disc brakes on the front wheels; however, many inexpensive vehicles still use drum brakes on the rear wheels. The rear wheels only supply about 20 to 30 percent of the total vehicle stopping power, so the somewhat lower effectiveness of drum brakes does not seriously compromise the vehicle's overall braking capability when they are used in the rear position, especially where smaller and lighter vehicles are concerned. Changing the pads on drum brakes is a good DIY project for the vehicle owner.
Instructions
- 1
Park the vehicle and block the front wheels to prevent movement. Do not set the parking brake. Loosen the lug nuts on both rear wheels about one full turn each. Jack up the rear end of the vehicle, set it securely on jack stands, and complete the removal of both rear wheels. If you are not familiar with drum brake maintenance, it's best to remove the drums from both rear wheels at the beginning of the job, so that an assembled brake can be used as a visual reference when working on the other brake.
2Remove the drums from both rear wheels by simply pulling the drum off the hub. On some models, the drum will simply pull off. On others, there will be retaining screws or bolts that must be removed first. Many older models have a central hub nut that is held in place with a crenelated lock-nut and cotter pin. For these models, first use pliers to remove the cotter pin. Remove the crenelated lock-nut, taking care not to bend or brake the crenelations, and then remove the hub nut. Remove the drum carefully, as the wheel bearing will likely come off with the drum. Do not allow dirt to get into the wheel bearing. If the drum is seized to the hub or backing plate, tap it firmly on the outer shoulder a few times with a plastic or rubber mallet to loosen. With the drums off on both rear wheels you will now be able to see both brake mechanisms. From this point on, work on the brake on one side while using the assembled brake on the other side as a reminder of how things should look when properly assembled.
3Remove the brake springs. Brake springs have hooked ends, and removal is accomplished by gripping one end of the spring with pliers and pulling to unhook it, and then unhooking the other end once the spring tension is released. First remove the large return springs that connect the two brake shoes, and then remove the smaller springs that provide tension for the self-adjusting mechanism and some of the operating levers.
4Remove the brake self-adjuster mechanism from in between the brake shoes. With the springs removed, the self-adjuster will slide out from between the shoes. Some models also have a metal strut that connects the shoes. If a strut is present, slide it out from between the shoes.
5Remove the brake shoe hold-down pins. There will be one pin for each brake shoe on smaller models, and two pins for each shoe on larger models. Some pin types are removed by depressing the pin with a hex key or large screwdriver and then rotating counterclockwise until the pin releases. Other models have spring clips on the ends of the pins, and these are removed by rotating the clip and the pin with pliers until the clip releases.
6Remove the front brake shoe from the backing plate by pulling it off of the hold-down pin. Push the hold-down pin out through the back of the backing plate. Remove the retaining clip that holds the parking brake cable to the rear brake shoe by pulling the clip off with pliers. Slide the end of the cable out from its mount and then pull the shoe off the backing plate. Push the hold-down pin out through the back of the backing plate.
7Clean the backing plate and all parts by spraying with brake cleaning fluid. Catch the used fluid in a catch pan. Use rags and a wire brush to remove stubborn dirt.
8Lubricate the points on the backing plate that contact the brake shoes with brake grease. Do not use too much grease, or excess grease may find its way onto the shoe linings or drum friction surface. Unscrew the self-adjusting mechanism, pull out the push-rod end, and lubricate the threads and push-rod female end with brake grease before reassembling.
9Reassemble the brake using new brake shoes by following the disassembly steps in the reverse order. Use the assembled brake as a visual guide. Be sure to set the self-adjuster mechanism to its shortest length so that the new brake shoes do not prevent the installation of the drum.
10Repeat the procedure on the other brake. Replace the wheels and lower the car. Pump the brakes a few times to set the mechanism. Perform a few stops in reverse to set the self-adjusters. Test the brake operation before driving normally.
