Removed broken portion of old knob and installed new knob. The biggest problem was getting the old portion in the up position, then trying to get it off. Had to use a pair of regular pliers and a pair of needle nose pliers. Once in the up position the needle nose pliers were used to hold the screw and broken portion of knob was loosened with the other pair of pliers. Once off partially switched needle nose pliers to hold base of knob screw and finished removal with the othe pair of pliers. The broken portion of the old knob seemed like it was glued or melted on. Once off the replacement went right on, and is now working fine.