Changing the upper cage pivot is the formidable task.
I would not attempt it without the tools I made for this task long ago. Unfortunately stolen with an old tool box. Here is what I did. Took two flat nosed punches (or pin drifts) from the local hardware store and cut a shallow depression in each with a 3mm ball end mill, yes used a lathe to do this. These are for reassembly. Lots of work already. I felt it was necessary to get the correct look for the replacement pin. I do not think you will get the old one to reuse with good results. Maybe possible, just don't expect to. Now that one is in for a pound, punch the old pin in the center, selecting the side that is smaller, drill a small bore with an .030 drill bit about .050 deep, then using a broken drill (perhaps the one just used) use that to tap out the pin. this is done best against a vise or block to take the force, with a hole or open jaws to let the pin pass. the trick on reassembly is not to let the cage tabs or ears to bind against the arm, I used a .003 or .005 bit of shim stock to keep things limber. removed after peening. Lots of work. I do not know where to get a new pin now, they used to be a replacement part, packaged in a bag of 5 or so.
John Jorgensen
Torrance Ca