FWIW, guys, on my early 235, I had the "grey soot" streaks behind the left
outboard elevator hinge early on (at maybe 300 airframe hours). I replaced
all the elevator hinge pins with the Teflon sheathed wire at that time and
haven't noticed any further wear there over the next 500 hours.

As a result, I watched the aileron hinges carefully for development of
excessive wear (my criterion: ANY noticeable wear) and replaced those
hinge-pins with the same material as the elevator pins at about 400 hours.
Same results.

Flap hinge-pins have not needed replacement.

Having seen high-speed motion pictures of wind tunnel flutter testing - and
the catastrophic results of various defects, including loose flight control
hinges, among others - I wouldn't fly my LNC2 with even the slightest slop
in those hinges.

Dan Schaefer