need to pull that pivot bolt and check the bearing in the axle.
the top of the axle bearing gets worn down and next it wearing into the axle itself.
the bronze bearing inserts are not that much, most old tractors need new bearings by now.
I replaced the axle bearing in my old to-35 fergy, now I keep it lubed with spray graphite from napa.
always a difference of thought on if this wear point should have had a grease fitting.
you do not want the axle hole to get egg shaped due to the bearing wearing through, if so you have to have the axle hole rebuilt to accept the new bushing..