Ball joints are an important part of an Audi's suspension system that connect the wheel hub to the rest of the suspension. Signs that ball joints are bad include awkward sounds from the suspension like clunking over bumps as loose ball joints rattle, steering becomes hard to control as misaligned wheels caused by worn ball joints can drift from side to side, and uneven or excessive tire wear on the inner or outer edges from improper wheel alignment. Additional indicators are excessive vibrations felt through the steering wheel or suspension from shaking ball joints.