It sounds like your on the right track, maybe your bad luck (and bad mechanic) is in the past. I do wonder if some of the axle parts were missing from the beginning or they lost them or something, it kind of boggles my mind they would put it together like that. Mine pulls some on a crowned road, more with a passenger, runs straight if the road's flat. It will pull some at highway speed (wind resistance) but it's a Royal Enfield and doesn't really go highway speed. I drive it more often without a passenger, so I keep it this way. Just keep an eye on everything when you get it back, don't let something sneak up on you. On mine I didn't like the shock bolts threading in with no lock nuts, so I modified that. Sidecars are a lot of fun, it's joined the list of magical objects in our household, along with the tandem bicycle and the tandem kayak. Have fun!
@KAmes I just got the same sidecar you did. I have to still put it together and make modifications for it to be used with my Harley Street Glide. Can you tell me what you had done? Also can you send me more pics of yours?
