Ball joints act like hinges and connect the suspension control arms to the steering knuckles with a rotating, spherical stud and a socket, giving the wheels a wide range of movement — from side to side for steering, and up and down for going over bumps.
Some cars have upper and lower front ball joints (Toyota Hilux), and depending on the suspension design either can be the load-bearing joint that carries the vehicle’s weight (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.
How do I know if my ball joint has gone bad?
When worn, ball joints allow too much suspension movement, and this looseness can result in more vibrations, squeaks or rattles on bumpy surfaces or when turning. Other signs of worn ball joints include uneven tire wear and steering that tends to wander. These symptoms also can apply to other suspension and steering issues, so a thorough inspection should be performed by a qualified mechanic before replacing one or more ball joints.
How often should I replace my ball joints?
Ball joints often last for several years and roughly 100,000 miles, but it’s not unusual for them to wear enough that they need to be replaced after about 75,000 miles. Driving on rough roads can accelerate their decline, and weight-bearing lower ball joints tend to wear faster. Generally, only the ball joints that are worn need to be replaced, and they need not all be replaced at the same time.
Why do I have to replace the ball joints?
If you want a smoother ride, you’ll want to replace bad ball joints. If warning signs aren’t addressed, a worn ball joint can eventually break and damage a control arm or other suspension parts.