I have some confusing information about this. I cleaned the finder when I got my IIc, including cleaning and relubricating the arm pivot, I used moebius oil. After I was done, I had this slow movement thing, and the RF wouldn't stop in the right place unless the lens was moved from the close distance direction (!). I can't remember if it did it before, the finder was pretty much useless. After finally figuring out that was happening and getting the RF set correctly, it was still doing that slow thing, and still not settling in the right place when moved from the infinity direction.
I abandoned the thing in a drawer for 9 months or so, disappointed. Took it out later and the problems were gone. My first thought was that I didn't get the bearing lubricated right, my second is that it was worn, and took a while to get 'seated'.
You'll have to take off the RF assembly to get to the pivot, and then re set the RF for distance, maybe vertical alignment. There is a guide at retinarescue. Be sure not to turn the camera over with the cover off and let the rod fall out, like he says.
I do think Chris Sherlock is a good option. I think a CLA'd IIIc is worth $150. I still don't know exactly what happened.