Rebuilding the wheel cylinders in your vehicle's drum brake system will repair leaks, and restore the system to near-factory performance. The key to successfully performing this repair project is to identify the type of wheel cylinder you have on your vehicle. Aluminum wheel cylinders can not be honed like a cast iron or steel wheel cylinder without damage to the protective anodizing in the cylinder bore. This does not mean aluminum cylinders can't be rebuilt, only that special precautions must be taken. Any wheel cylinder with excessive corrosion should be replaced.
Instructions
- 1
Lift and support the vehicle with the floor jack and jack stands. Remove the wheels from the axles that are to have the wheel cylinders rebuilt, and place them out of the work area to avoid tripping hazards.
2Remove the brake drums from the rest of the brake system. Sometimes the drum will be stuck due to rust buildup around the axle. A few sharp blows, with a hammer, around the edge of the drum will break it free of the rust.
3Remove the two return springs that hold the brake shoes tight against the wheel cylinder with a brake spring tool. Slide the brake shoes out of the way. The return springs are the long springs connecting the brake shoe to the pivot pin located above the wheel cylinder on the backing plate.
4Remove the dust boots, pistons, cup seals and spring from the inside of the wheel cylinder. New dust boots and cup seals are supplied with all wheel cylinder kits, and some kits supply a new inner spring as well.
5Hone the inside of the wheel cylinder with a wheel cylinder hone, attached to an electric drill, if the cylinder is made of cast iron or steel. Aluminum wheel cylinders should never be honed. Aluminum wheel cylinders have a hard, protective, anodized surface inside to prevent corrosion. Honing will remove this surface and cause excessive corrosion and wear. Instead, clean the inside of the aluminum cylinder with soapy water and a green scotch-brite pad to remove debris that collects in the cylinder bore.
6Clean and dry the wheel cylinder with soapy water to remove residue from honing. Coat the inside of the wheel cylinder bore and the rubber cup seals with a liberal amount of clean brake fluid. Insert the spring into the bore of the wheel cylinder. Install one cup seal, and one piston, in each end of the cylinder bore. Install the wheel cylinder dust boots onto the wheel cylinder.
7Reposition the brake shoes, and reinstall the return springs with a brake spring tool. Avoid using pliers, side cutters or a screwdriver to reinstall the return springs. Damage to the spring and painful injury could result.
8Reinstall the brake drum. Bleed the brakes according to the manufacturer's bleeding sequence located in the service manual. Reinstall the wheel, and lower the vehicle back onto the ground. Pump the brake pedal a few times, and test drive to verify the repair.
