Stabilizer link, control link or link is a suspension member, that attaches at only two points. One point being the body or frame of the vehicle and the other point attaching to the knuckle, upright, axle or another link. The link pivots on either a bushing or a ball joint at each attachment point.Over time, the Stabilizer bar link ball joints wear out. The first sign of a worn-out sway bar link is a knocking noise from the suspension when driving slow over road bumps. A worn-out sway bar link will show a free play when pushed up or down. Steering and handling are also negatively impacted when they begin to wear out.