I've got an old 118 B Galion that needs a rear wheel brake cylinder serviced. According to the shop manual that I have you have to jack up the opposite side tandem wheels and remove the near side wheel nut. Then you have to attach a "Knocker" by threading it on the end of the tapered axle. Once that's done you have to hit the "knocker" with a sledge hammer until the axle moves out of the near wheel that needs servicing then let the opposite side wheels down and jack up the near side wheels and remove the wheel. Thus exposing the brake assembly. Can anyone tell me where I might start looking for the appropriate "knocker?" I've never seen (or heard of) one nor do I have any idea where I might get one. Also, is there an alternative way to remove the wheel to service the cylinder? Any help or advice is appreciated. Thanks. SS