creeg, the mode selector switch shouldn't be riveted together. It should be held together with little star screws. I have a spare selector switch at home that I got form another member here. I took it apart and cleaned it out in my garage so your shop should be able to do it. I'm keeping the switch for when mine might go out, but I would be happy to take pictures of the one that I have (both together and apart) if you need me to.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless