Lower Ball Joint

The lower ball joint is pressed into rear lower control arm and has a tapered stub for attachment of ball joint to knuckle. See Figure . The tapered stub of ball joint is attached to knuckle using a special nut and washer.

Due to knuckle being made of aluminum and ball joint being made of steel (dissimilar metals), galvanic corrosion can occur between pieces. For this reason, ball joint and ball joint stub have a corrosion protective coating applied to them. The ball joint is a pivotal joint on the lower control arm that allows the knuckle to move with ease.