I bought an old Thule T2 bike rack, which had sloppy bushings -- whole rack wobbled and wasn't really usable. This is the original T2 rack, relabeled the "T2 Classic," not the Pro or XT or whatever the newer ones are called. Did some googling and measuring, and located a cheap source for the bushings used in the T2 rack: McMaster-Carr has them as part number 2938T15:
https://www.mcmaster.com/2938T15/

If you want to replace all the bushings in the rack, you need a total of 8. They pop out fairly easily with a hammer and screwdriver, and you can pop in the new ones with a hammer. Rack operates like new with new bushings.