The rack and pinion moves left and right to change the direction that the front wheels are pointing. Connecting the rack and pinion to the steering knuckle, or the part that the wheels are mounted to, are tie rods. The inner tie rod end is a ball and socket joint that is screwed on to the end of the steering rack. It is covered by a rubber boot to prevent dirt from contaminating the joint. A worn inner tie rod end may cause a clunking noise from the steering, looseness in the steering wheel, and uneven tire wear from the tires not being aligned correctly.