We used to have a 1968 Buick LeSabre. It had a tilt column. I should have saved it because the parts are the same. I still have the 1968 FSM and everything is the identical. [insert pic of me kicking myself in the butt]. So I see that the 1969 and up columns all use a similar upper shaft. But the bearing pre-load threaded nut was replaced with a big spring and a retaining clip. I wonder if that can be back-fitted? The '69 up part is pretty common and cheap. This is worth investigation.
