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
- To remove the wheel cylinder, jack up the vehicle and remove the wheel, hub, and drum.
- Remove the brake shoe assemblies.
- Disconnect the brake line at the fitting on the brake backing plate.
- Remove the screws that hold the wheel cylinder to the backing plate and remove the wheel cylinder from the vehicle.
- Installation is the reverse of the above removal procedure. After installation bleed and adjust the brakes as described earlier in this Section.
- Before servicing the vehicle, refer to the Precautions Section.
- Raise and support the vehicle safely.
- Remove the wheel and tire assembly.
- Remove the brakes shoes.
- Disconnect the brake line at the wheel cylinder.
- Remove the wheel cylinder bolts.
- Installation is the reverse of the removal procedure.
- Torque the bolts to 9 ft. lbs. (12 Nm).
- Bleed the brake system.
- Correct and adjust the brake fluid level.