Upper Ball Joint

The upper ball joint is the pivot point between the upper control arm and the spindle or knuckle support. Upper ball joints are also used in some 4WD drive vehicles with solid axles. In the case of a solid axle application, the upper ball joint connects the knuckle to the axle. The upper ball joint consists of a heat-treated ball stud that is mounting in a steel housing. The ball stud can swing and rotate in the housing, which allows the spindle or knuckle to pivot. Greasing the ball joint on a regular basis will greatly increase the life of the part.