1951 zenith tuner help

[Radiotronman]

I've got a blonde 1951 zenith tv(model H2253E) that is having mechanical tuner trouble. When I first got it, the tuner was frozen. After investigation, I took apart and found out that one of the gears was stuck. I got it loose, but when you turn the tuner, the gear works the nut loose and falls off. Is the bolt supposed to spin freely inside the fear itself? Is there a way to unfreeze it or does anyone have one from s junket set. This chassis (22H21) is very similar to my 1949-1950 porthole sets and should be the same gear. It's the one in the center of the three in the tuner drive. See pictures below...