Ball Joints: Carrying the Load
There’s a lot riding on your vehicles ball joints. Literally! Ball joints act like hinges and connect the suspension control arms to the steering knuckles with a rotating, spherical stud and a socket. This gives the wheels a wide range of movement; laterally for steering and up and down for navigating over rough surfaces. Some vehicles are equipped with upper and lower front ball joints. Depending on the suspension design, these can be a load-bearing joint that carries the vehicle’s weight. Note that load-bearing joints tend to wear out sooner. Vehicles with McPherson strut suspensions have only lower ball joints, and some vehicles also have rear ball joints.
Ball joints do wear out over time. When they do wear, they allow too much suspension movement. This can result in shimmies or shakes on smooth roads, meandering (wandering) steering that veers from straight, or uneven tire wear. Occasionally, they may give audible warnings that they need to be replaced by squeaking or clunking, especially over bumps or when turning.