The real problem is that you could get inside and tighten the prism - or whatever it is that is loose but once you have done it, they will need collimating. And THAT is the difficult thing to do with L11's and 12's. That's because in those, you have to use multiple eccentric rings to collimate two separate prismatic telescopes whereas with the old No2's and 5's you rotate a simple(?) prism on one or both and this prism is the actual objective lens. The L12 binos have a special collimator........
I think that I might have the parts list so you can see your way. But don't hold your breath.........