You can maintain and service the drum-brake wheel bearings by cleaning and repacking them with special grease. However, wheel bearings wear out, crack, and develop heat, hard and pitting spots over time. When the time comes to replace them, make sure you have the required tools for the job and the adjusting nut torque specification for your particular vehicle make and model. Then choose a clean working area to avoid contaminating the bearings and hub on your car.
Park your vehicle on a level surface.
Loosen the wheel lug nuts with a lug wrench on the wheel/tire assembly you will be working on.
Raise the wheel/tire assembly using a floor jack and support it on a jack stand.
Remove the wheel/tire assembly.
Detach the grease cap from the brake drum using a screwdriver and a hammer.
Remove the cottar pin that secures the nut lock and adjusting nut in place.
Pull the nut lock from the axle with a pair of nose pliers.
Unscrew the adjusting nut using an axle nut socket and ratchet.
Pull the washer from the axle using the nose pliers.
Wiggle the brake drum, if necessary, to pull the outer wheel bearing free from the axle.
Detach the brake drum from the brake assembly.
Lay the brake drum on a workbench and remove the grease seal and inner bearing from the back of the drum using a screwdriver.
Remove the inner and outer races from the drum using a large drift punch and hammer. Be careful to avoid damage to the hub.
Clean thoroughly the hub and drum using brake parts cleaner and a shop rag or lint-free towel.
Drive the new inner and outer races in place using a driving tool.
Grease the inner wheel bearing with high-temperature wheel-bearing grease using a bearing packer.
Place the packed inner-wheel bearing on its race inside the hub.
Fill partially the cavity inside the hub with high-temperature wheel-bearing grease.
Install a new grease seal using the driving tool.
Clean thoroughly the spindle on the axle assembly by using brake parts cleaner and a lint-free towel.
Replace the brake drum on the wheel assembly.
Grease the outer wheel bearing with high-temperature wheel-bearing grease, using a bearing packer and installing it on its race inside the hub.
Insert the washer and screw the adjusting nut by hand.
Ask a helper to rotate the wheel assembly as you tighten the adjusting nut to the torque specified by your vehicle manufacturer. Use a torque wrench and the axle nut socket. You may find the torque specification for your car make and model on your vehicle service manual. See the Tip box for more information.
Rotate the adjusting nut counterclockwise about 1/2 turn using the axle nut socket and ratchet.
Tighten the adjusting nut to the specification listed in your vehicle service manual, using the axle nut socket and torque wrench.
Fit the nut lock in place. Then insert and bend a new cottar pin to secure the adjusting nut and nut lock in place. Use the nose pliers.
Replace the grease cap.
Install the wheel/tire assembly and tighten the wheel lug nuts using the lug wrench.
Lower the vehicle and finish tightening the lug nuts.
You may find the vehicle service manual for your particular car make and model at most auto parts stores. In addition, the reference section of your local public library may have this manual available.