You should clean all corrosion or contaminates from the steering knuckle bore and the hub and bearing assembly, lubricate the steering knuckle bore with
Wheel Bearing grease or the equivalent, install the O-ring to the steering knuckle, install the wheel speed sensor to the wheel hub and bearing, install the wheel hub and bearing and splash shield to the vehicle, install the wheel hub and bearing mounting bolts, install the nut and washer retaining the wheel drive shaft assembly to the wheel hub and bearing, connect the electrical connection for the wheel speed sensor, install the wheel speed sensor and brake hose mounting bracket bolt to the steering knuckle, install the rotor and install the tire and wheel.