The upper control arm and balljoint must be replaced as a single unit. To begin removal, loosen the wheel lug nuts, raise the vehicle, support it securely on jackstands, and remove the wheel. If the vehicle has Automatic Ride Control (ARC), ensure the air suspension switch is turned off before raising the vehicle to avoid damage to the system components. Next, place a floor jack under the lower control arm and raise it slightly, keeping the jack in this position throughout the process. Remove the pinch bolt that secures the upper balljoint stud to the spindle/steering knuckle, then take out the upper control arm pivot bolts and detach the arm from the frame. For inspection, check the control arm bushings for cracks and tears; if damaged or worn, take the control arm to an automotive machine shop for new bushings, as this requires specialized tools. If the balljoint is worn out, the control arm must be replaced. For installation, position the control arm on the frame and install the two pivot bolts, cams, and nuts, tightening them to the specified torque. Insert the upper balljoint stud into the spindle, install the pinch bolt and nut, and tighten the nut to the specified torque. Finally, install the wheel and tighten the lug nuts to the specified torque, and have the front-end alignment checked by a dealer service department or an alignment shop.