I am having a dickens of a time with the 57971, It worked fine when I bought it (so naturally I had to mess with it) Started out by looking for exploded parts diagrams online and with AI. No luck there. I went ahead and removed the bottom brake shoe part and found what I believe are called Wheel Wipers . I bent them up pretty badly removing them to get at the gears to be greased. The black wire leading into the motor area also came loose. next I removed the Bottom of the gear case. The gears were in pretty good shape. I put a sparing about of teflon grease on them and Oiled the bearings. In the process the Wheels came out of their resting places and I lost registration on them. I learned the hard way how to quarter the wheels after hours of trial and error. It was a little simpler because I had not removed the piston rods. I straightened the Wipers but I think I installed them backwards and the manual turning of the wheels bent them up again. I gently annealed them with a hot air gun and straightened them again. When all was put back together I placed the chassis on the track (minus the housing) so as to find the spot where the errant black wire from the wipers had been connected. It shorted the track immediately and I have been unable to ascertain why as of this writing. Anyway, there's my story in a nutshell. I am Looking forward to the forums!