This ball joint connects the steering linkage to the wheel hub, allowing the steering knuckle to pivot while transmitting lateral and vertical loads from the wheel assembly to the suspension. It is the pivot point between the control arm and the steering knuckle. Wear in this joint produces free play that causes imprecise steering, uneven tire wear, and a knocking sound when turning or driving over uneven surfaces. The threaded shank is machined to match the original taper in the steering arm or knuckle, so the joint seats correctly without additional shimming. On installation, tighten the retaining nut to the manufacturer's torque specification and install a new cotter pin.