Abstract: A portable device for resurfacing in situ a fifth wheel king pin depending from the underside of a transport trailer. The device includes an elongate member, which is vertically disposed when in use, engagable at its upper end with the pin and supportable at its opposite end on a surface below the pin. Pivotably mounted on the elongate member, for swinging thereabout, is a first arm. Movably mounted on and extending from the end of the first arm remote from the elongate member is a second arm. The second arm is adjustably positionable relative to the first arm. The second arm includes, toward its end remote from its movable connection with the first arm, a device, preferably an adjustably mounted power driven grinder, for resurfacing the king pin.