Ball Joints, Replacement, Upper, Bolt-On, Greasable, includes Hardware, for EMU-UCA005 Control Arms, Each. Signs of worn ball joints include steering wheel pull, uneven tire wear and front-end shimmy. Old Man Emu ball joints make an ideal replacement for your worn upper and/or lower stock originals. While the upper and lower ball joints may serve different type functions, they both work together to keep steering reliable and responsive. Designed to maintain alignment and absorb radial loads, such as turning forces, upper ball joints enable proper rotation of steering knuckle. Acting as a pivot point for the steering system, lower ball joints can either be load-carrying or follower types depending on the suspension design. When you need to replace a ball joint, look to Old Man Emu for the suspension components you need for the repair. Order the upper and/or lower ball joints for your application.