The 2003 Chevrolet Trailblazer was equipped with a 4.2-liter inline-six cylinder, or optional 5.3-liter V-8. Available in two- or four-wheel-drive, the four-wheel-drive Trailblazer used a coil spring front suspension with upper and lower control arms. The front wheel bearings on the four-wheel-drive Trailblazer are part of a hub assembly and are not serviced separately. The hub must be replaced.
Park the Trailblazer on a level, paved surface and set the parking brake. Place wheel chocks behind the rear wheels. Loosen the lug nuts on the front wheels. Remove the center cap on the wheel hub. Loosen the hub nut two turns with a ratchet and socket. Raise the front of the Trailblazer with a jack and support with jack stands. Remove the lug nuts and wheels.
Unbolt the brake caliper bracket from the steering knuckle. Remove the caliper and bracket. Tie the caliper to the coil spring with a piece of wire. Remove the rotor. Remove the hub nut with a ratchet and socket.
Place a brass drift against the center of the axle shaft and strike it with a hammer to disengage the axle from the hub.
Disconnect the ABS sensor wire from the harness by squeezing the sides of the connector and pulling the two ends apart. Unclip the ABS wire from the lower control arm. Remove the three hub mounting bolts from the back of the steering knuckle with a ratchet and socket.
Remove the hub and splash shield from the knuckle. The hub should slide off of the axle. Take note of where the ABS sensor and wire are on the hub in relation to the knuckle so you install the new hub the same way.
Mount the splash shield and a new hub on the knuckle while sliding the axle shaft through the hub. Guide the ABS sensor wire through the knuckle. Install new mounting bolts and use a torque wrench and socket to torque the bolts to 77 foot-pounds. Install a new hub nut and snug it down with a ratchet and socket.
Press the plastic clip on the ABS wire into the lower control arm and push the connectors together. Install the rotor. Slide the caliper onto the rotor and install the bracket bolts. Torque the bolts to 118 foot-pounds.
Mount the wheel and install the lug nuts. Raise the Trailblazer, remove the jack stands and lower it to the ground. Torque the lug nuts to 100 foot-pounds. Torque the axle nut to 103 foot-pounds. Install the center cap. Remove the wheel chocks.
