EDIT: My mistake, it's an SRAM ESP 3.0 derailleur and not Shimano. I can't see any way to edit the message title, ooops
I was doing some general maintenance on a friend's Trek 7100 hybrid, and was unpleasantly surprised to find the the rear derailleur pulleys are riveted rather than mounted with screws . Using a can of spray solvent with an extender nozzle and some teflon chain lube with a needle attached, I was able to flush and relube the idler pulley well enough so it turned pretty freely again. However, I was not successful with the same approach to clean and lube the jockey pulley. It still has a fair amount of drag and binding in it .
So, have derailleurs (albeit cheap ones) become something you throw away rather than service? Seems a pretty p*ss poor idea to me, do they think folks will just shell out bucks to their LBS for a new derailleur and installation labor when their pulleys get dirty? What's the possibility of drilling out the rivets and replacing them with screws? I know I'd have to use nuts on the back of the screws, since the back plate of the cage is plastic/nylon and probably not good for tapping with threads. Grrrrr.....