Car is 114k, but it was hit in rear right in 1998. The arm and possibly some other components on there now came from an older car - 76 or something. I know this from some writing visible on the arm. I wouldn't be surprised if at least right rear hub has more miles than rest of chassis.

I'll do some more diagnosis, but why do I need to put a spare rim on it?

I feel the same about ball joints and cracked boots, this guy in particular won't take my money to install them. I had bought a new rubber boot and was thinking about replacing the super deteriorated one but not sure if I can do that while it's in place?