Closed cell foam insert for a king pin/knuckle arm assembly

A king pin connection between a vehicle steering axle and knuckle arm. The king pins are pivotally connected to either ends of an axle beam and pivotally connected to steering knuckles which in turn are connected to the wheels. Each king pin is rotatably mounted within a cylindrical bore on the steering knuckle and retained therein by a king pin cap disposed adjacent at least one end. A closed cell foam insert is disposed between the king pin and king pin cap. The insert is preferably axially compressed so that it may further compress and expand to substantially or nearly completely occupy the volume between the kingpin and kingpin cap. A grease fitting may be formed on the kin pin cap and a grease passage formed in the insert to facilitate lubrication.