I am replacing one of the transom screw clamps and I would like to know how to keep the part at the end of the bolt (that presses up against the transom) *ON* the bolt. There isn't a screw holding it in place and the end of the bolt is smooth. This is the entire transom screw clamp assembly, there are no additional parts needed as far as I can tell. Any help would be appreciated, as I'm stumped.