Moog K80040 Control Arm and Ball Joint Assembly Problem Solver patented cover plate design allows for tighter tolerances vs traditional cover plate designs, providing a more durable and extended life part. Exclusive cover plate protects against contaminants leaking into the bearing surface. Full ball metal stud provides 36 degrees of smooth, consistent, rotational movement resulting in more responsive steering. Greaseable socket design allows new lubricant to flush contaminants from the assembly, reducing corrosion and wear Loose or worn chassis parts can lead to premature tire wear