[AT] Super M generator belt / tensioning bracket

[Robert L. Holtzer]

On 6/25/2011 5:03 PM, Dean Vinson wrote:
> Hmmm.  Last year I bought a 1953 Super M that had been restored several
> years ago but is still in near flawless shape.  Given the obvious attention
> to detail in most areas, two things seemed odd to me:  it had an old and
> rather ragged fan belt on it, and the generator tensioning bracket was
> missing.  (Tension on the generator belt was maintained just by tightening
> the mounting bolts at the bottom of the generator, around which the
> generator can pivot if the bolts are loose, since the adjustable bracket
> that normally mounts at the top of the generator just wasn't there).
>
> Last fall I replaced the fan belt, and replaced the generator belt at the
> same time.  The old generator belt looked fine but I figured as long as I
> was going to the trouble of replacing the fan belt I'd do them both on
> general principle.  Both new belts came from OEM Tractor Parts.
>
> I finally got around to looking for a tensioning bracket and found one on
> eBay a while ago, and today went to put it on.  It's inexplicably too short:
> Even in the "all the way out" adjusted position, the generator is so far in
> toward the engine that the belt just hangs loosely draped over the pulley.
>
> The tensioning bracket was advertised as being from a Farmall M and came
> with the bracket that actually mounts the generator to the tractor.  Neither
> one has any sign of a part number on it, but the mounting bracket is exactly
> the same size as the mounting bracket on my tractor so it seems likely that
> they were indeed from an M.  The M and Super M parts books confirm that the
> generator brackets were the same for both tractors.
>
> The generator belt is marked "04710 Made in Mexico" and "756962".  Neither
> of those is the Farmall part number, and a Google search didn't tell me
> anything about them.
>
> So the question is, how can that bracket be too short?  Either it's the
> wrong bracket (perhaps from an H?), or the belt is too long.
>
> Or, hmmm, the pulley could be smaller than normal?  The tractor's been
> converted to 12 volt... could the restorer have put a small pulley on there
> to spin the generator faster as part of that conversion?  It doesn't look
> unusually small--I just went back out and measured, and the front face of
> the pulley is an even 4" in diameter.  If it's not original, it doesn't seem
> like it could be so much smaller than original that it would create all that
> slack in the belt.  So, back to the bracket being too short or the belt
> being too long... neither of which seems terribly likely.  Any thoughts?
>
> Dean Vinson
> Dayton, Ohio
> www.vinsonfarm.net
>
>
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at
>
Looking at a pre-rebuild picture of my M, it appears the original 
generator mounts essentially vertically against the head or valve cover 
and has a split pulley for tension adjustment.  Been a while since I 
worked on it and it is no longer in my possession.

Bob Holtzer