Wheel Bearing Replacement Instructions for a '99 GMC Sierra

The "Sierra" nomenclature in GMCs lineup of pickups began in 1975, but the maker used different variations of Sierra to indicate the trim level of its existing C- and K-series pickups. The trim levels, in order from entry level to top level, were Sierra, Sierra Grande, High Sierra and Sierra Classic. In 1999, GMC used the name Sierra to identify its brand-new lineup of pickups. The 1999 GMC Sierras base format was the 1500, with a 4.3-liter V-6 engine and two-wheel drive. The front wheel bearings on the base-level 1999 Sierra were a part of the hub assembly, which means that you must replace the entire hub when the bearing fails.

Instructions

Removal

1

Loosen the lug nuts on the wheel with the failed bearing, using a breaker bar and socket. Lift the front of the Sierra with a floor jack and slide jack stands under the trucks frame rails. Lower the Sierra onto the jack stands. Remove the lug nuts and pull the wheel off the truck.

2

Remove the two bolts securing the caliper bracket to the steering knuckle, using a breaker bar and socket, and lift the caliper and bracket off the steering knuckle as an assembly. Hang the assembly from the front suspension spring, using a bungee strap.

3

Pull the brake rotor from the front hub. If the rotor is seized, lightly strike the rear of it with a rubber mallet to free it.

4

Unfasten the bolt securing the antilock brake system speed sensor wiring-and-brake hose bracket to the steering knuckle, using a ratchet and socket. Trace the ABS speed sensor wiring until you find where its harness plugs into the Sierras harness and unplug the ABS wiring harness from the Sierras harness.

5

Look on the rear of the steering knuckle and find the bolts securing the wheel hub to the steering knuckle. Remove these bolts with a breaker bar and socket. Pull the hub assembly from the steering knuckle.

Installation

6

Clean the steering knuckles mating surface, using a wire brush, and apply a thin coat of wheel bearing grease to the hub assemblys bore inside the steering knuckle.

7

Guide the hub assembly into the steering knuckle, aligning its bolt holes with those in the steering knuckle. Hand-thread the hub assembly bolts, then tighten them to 133 foot-pounds, using a torque wrench and socket.

8

Connect the ABS wheel speed sensors wiring harness to the Sierras wiring harness and align the ABS wheel speed sensor wiring-and-brake hose bracket with the bolt hole in the steering knuckle. Hand-thread the brackets retaining bolt, then torque it to 106 inch-pounds, using an inch-pound torque wrench and socket.

9

Slide the rotor onto the new hub and lower the caliper and bracket assembly onto the steering knuckle. Hand-thread the caliper bracket bolts, then tighten them to 129 foot-pounds.

10

Reinstall the front wheel on the front hub and hand-tighten the lug nuts. Lift the truck off the jack stands and remove the stands. Lower the vehicle to the ground and tighten the lug nuts, in a crisscross pattern, to 125 foot-pounds.