Moog K620257 Control Arm/Ball Joint Assembly Problem Solver powdered metal gusher bearing design enables grease to flow through the bearing to the stud for reduced friction and enhanced strength and stability. 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. Moog engineered steel composition results in a stronger component 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