Ball joints are of a stud and socket design that attaches the control arms to the steering knuckle. The ball joint allows the turning of the wheel left or right. It also allows for the up and down movement of the Suspension. The Ball Joints can also hold the Suspension Spring system together. Worn Lower Ball Joints typically will cause inside edge wear on tires, which will be worn smooth, while worn upper Ball Joints will cause outside edge wear. Excessively worn ball joints can also make a clunking noise which is caused by the stud banging into the socket. Also a steering wheel off center, or drifting left or right can result. Ball joints that are excessively worn can come apart. This can cause the tire and wheel assembly to be pushed back and up into the fender as the suspension can no longer hold up the vehicle. Loss of steering control also occurs.
Morris Brothers Motorsports recommends a wheel alignment once a year. In order to do a proper wheel alignment, the suspension, including the ball joints would all be checked for excessive wear.