The lower control arm balljoints on models from 1979 to 1986 and the upper control arm balljoints on models from 1987 and later cannot be replaced individually; if worn, the entire control arm must be replaced, although the lower control arm balljoints on 1987 and later models are replaceable. To check for wear, raise the vehicle and support it securely on jackstands, then visually inspect the rubber boot for any cuts, tears, or leaking grease, which would necessitate replacement. Use a large prybar to push the balljoint up and check for excessive vertical or lateral movement; any movement indicates a worn balljoint. An assistant can shake the tire while you check for looseness at the balljoint stud nut, which may suggest a worn stud or a widened hole in the steering knuckle boss, requiring replacement of both the steering knuckle and balljoint if the latter issue is present. For replacing the lower balljoint on 1987 and later models, loosen the wheel lug nuts, raise the vehicle, and support it securely on jackstands. Remove the circlip from the balljoint stud and loosen the castle nut, then separate the balljoint from the steering knuckle using a balljoint separator and remove the nut. Take out the three bolts retaining the balljoint to the lower control arm and slide the balljoint out. To install the new balljoint, position it on the lower arm and install the bolts without tightening them yet. Insert the balljoint stud into the steering knuckle, install the nut, and tighten it to the specified torque. Finally, tighten the balljoint-to-lower arm bolts to the specified torque, install the wheel and lug nuts, lower the vehicle, and tighten the lug nuts to the specified torque.