2009 Mercedes-Benz ML320 Suspension Ball Joint Replacement Cost

To diagnose a worn ball joint, a shop will raise the vehicle on a hoist and then grasp the tire at the top and bottom and rock the wheel back and forth. A worn ball joint will present a clunking sound or sensation when this test is performed. The technician will also look for a torn or leaking boot on the ball joint. A worn ball joint may also be suspected if the tires are showing signs of unusual wear on the inside or outside edges.

To replace a ball joint, with the car lifted, the technician will first remove the front wheel. Then, the ball joint is disconnected from the control arm and the steering knuckle, the suspension is separated to allow the ball joint to come free, and the new part is installed. Some vehicles require that the steering knuckle be disconnected from the strut in order to get to the retaining nut on one side of the ball joint. Either way, the tension between components in the suspension may make this process difficult.

RepairPal recommends getting a four-wheel alignment after the ball joint has been replaced. If the tires show signs of significant wear, new tires would also be a good idea.

The front suspension components often have a good deal of tension between them. This could make separating the steering knuckle and the control arm from the ball joint difficult. A ball joint with tapered studs is sometimes difficult to remove from its mounts in the steering knuckle or control arm. Also, the vehicle needs to be safely raised and supported in order to complete this repair.

On most vehicles, replacement of a ball joint is an intermediate DIY repair. Care needs to be exercised when lifting and supporting the vehicle to prevent serious injury. If you're not comfortable with lifting a vehicle, or with working on parts under tension, have the job done by a professional mechanic.