A failing wheel bearing will cause noise and vibration in the front corner of your car. The bearing in the 2004 Chevrolet Impala is built into the wheel hub and designed to be replaced as a single unit. This reduces the number of special tools you will need, because there is no need to pull or press the bearing. Expect to spend about half an hour replacing the wheel hub and bearing assembly.
Loosen the lug nuts with a lug wrench. Lift the corner of the vehicle and place it securely on a jack stand. Remove the lug nuts and wheel. The lift point is directly behind the front tire. See your Impala's owner's manual for a diagram illustrating where to place your jack.
Unplug the ABS speed sensor. The electrical connection is behind the brake rotor.
Unbolt the brake caliper and slide it off the rotor. Hang it out of the way with a piece of wire to prevent wear on the brake line.
Remove the bracket that retains the caliper and slide the rotor off the studs.
Unscrew the nut in the center of the hub. Discard it--the nut should be replaced with the hub and bearing assembly.
Push the drive shaft out of the hub and bearing assembly by attaching front hub spindle removal tool J 28733-B or equivalent to the studs and tightening the center to push on the shaft.
Unbolt the hub and bearing assembly from the steering knuckle. Holes in the hub provide access to the bolts. The bolts should be replaced with the hub and bearing.
Bolt in the replacement hub and bearing assembly using new bolts torqued to 96 ft-lbs. Push the drive shaft into place and install the hub nut, tightened to 96 ft-lbs.
Attach the caliper bracket, torquing to 133 ft-lbs. Replace the rotor and caliper. The caliper bolts should be tightened to 70 ft-lbs. of torque. Plug in the ABS sensor, slide on the wheel and hand-tighten the lug nuts. Lower the car and finish tightening the lug nuts.
