Wheel cylinder overhaul kits may be available, but often at little or no savings over a reconditioned wheel cylinder. It often makes sense with these components to substitute a new or reconditioned part instead of attempting an overhaul.
If no replacement is available, or you would prefer to overhaul your wheel cylinders, the following procedure may be used. When rebuilding and installing wheel cylinders, avoid getting any contaminants into the system. Always use clean, new, high quality brake fluid. If dirty or improper fluid has been used, it will be necessary to drain the entire system, flush the system with proper brake fluid, replace all rubber components, then refill and bleed the system.
- Remove the wheel cylinder from the vehicle and place on a clean workbench.
- First remove and discard the old rubber boots, then withdraw the pistons. Piston cylinders are equipped with seals and a spring assembly, all located behind the pistons in the cylinder bore.
- Remove the remaining inner components, seals and spring assembly. Compressed air may be useful in removing these components. If no compressed air is available, be VERY careful not to score the wheel cylinder bore when removing parts from it. Discard all components for which replacements were supplied in the rebuild kit.
- Wash the cylinder and metal parts in denatured alcohol or clean brake fluid.
- Allow the parts to air dry or use compressed air. Do not use rags for cleaning, since lint will remain in the cylinder bore.
- Inspect the piston and replace it if it shows scratches.
- Lubricate the cylinder bore and seals using clean brake fluid.
- Position the spring assembly.
- Install the inner seals, then the pistons.
- Insert the new boots into the counterbores by hand. Do not lubricate the boots.
- Install the wheel cylinder.
Removal & Installation
- Safely raise and support the vehicle.
- Remove the rear wheel and the drum.
- Remove the spring on the adjuster lever.
- Remove the shoe-to-shoe spring.
- Remove the auto adjuster assembly.
- Place a drain pan under the wheel to catch the brake fluid and disconnect the brake line from the rear of the wheel cylinder.
- Remove the wheel cylinder mounting bolts and the wheel cylinder.
- Install the wheel cylinder on the backing plate. Tighten the mounting bolts to 7 ft. lbs. (10 Nm).
- Connect the brake line the wheel cylinder. Tighten the line fitting to 11 ft. lbs. (15 Nm).
- Add brake fluid to the reservoir and leave the wheel cylinder bleeder screw loose. Brake fluid will start the flow into the wheel cylinder and may save time when bleeding the brake system later.
- Install the auto adjuster assembly.
- Install the shoe-to-shoe spring.
- Install the spring on the adjuster lever.
- Install the drum and the wheel assembly.
- Lower the vehicle and bleed the brake system.