The wheel bearings in your 2002 GMC Sierra are housed in a sealed hub and bearing assembly. The bearings in this truck are not serviceable and must be replace with the hub and bearing assembly as a unit. Also included in the hub and bearing assembly is the ABS wheel speed sensor and exciter ring. While this unit is more expensive than a simple tapered roller bearing, the replacement procedure is greatly simplified and reduces the risk of bearing failure caused by improper lubrication and excessive bearing pre-load.
The process for replacing the hub assembly is the same, except for one step.
Block the rear wheels with wheel chocks and apply the parking brake. Raise and support the side of the truck that has the faulty wheel bearing using a floor jack and jack stands. Remove the wheel using a lug wrench.
Remove the two 15 mm brake caliper bolts that attach the caliper assembly to the steering knuckle, using a socket and ratchet. Lift the caliper off the rotor and hang it from the upper control arm, using a piece of stiff wire. Use a pair of wire cutters to break off the factory installed brake rotor retaining clips if they are still present. Slide the brake rotor off the hub assembly.
Remove the axle nut in the center of the hub -- on four-wheel-drive models only -- using a 36 mm socket and ratchet. Unplug ABS sensor wiring from the back of the hub assembly. Remove the three 15 mm hub and bearing assembly bolts from the back of the steering knuckle. Slide the hub assembly out of the steering knuckle.
Install the new hub and bearing assembly into the steering knuckle and tighten the bolts. Install the axle nut on four-wheel-drive models and torque the nut to 133 foot-pounds, using a torque wrench. Plug the ABS sensor wiring into the new hub assembly.
Reinstall the brake rotor and caliper assembly. Torque the bolts to 129 foot-pounds. Reinstall the wheel and torque the lug nuts in a star pattern to 140 foot-pounds. Remove the jack stands and lower the truck slowly to the ground. Remove the floor jack and pump the brake pedal until the pedal is firm.
Lower and test drive
