I agreed with you because of the flipping the collar mention. :D
Didn't those have a shouldered top on the upper bushing?
Except for something missing between the two I don't see how it hit the bottom of the casing.
Yep.:D
It does look like the collar could be flipped then 180 the shaft to get the pin opening lined up and slip it back up there.
Doesn't explain the hitting inside the case.
Didn't those have a shouldered brass upper bushing that the shaft sat on?
