[Farmall] O-12 chores

[olmstead at ridgenet.net]

The Farmall list has been seriously short on notes from people workin' on
tractors lately, so maybe it's time to relate another of my ongoing
adventures.

I drove my Volkswagen Golf to the EGE&TA swapmeet in Tulare, CA back in
November.  I knew I was picking up a couple hundred pounds of parts, but
nothing that the VW couldn't handle.  Didn't even slow me down; I still
wound up buying a 1936 McCormick-Deering O-12. Seemed that the seller was
more or less going my way, so he could deliver it after the swapmeet...

The odd thing about this tractor was that it actually ran.  We started it
up while it was still on the seller's trailer.  Smoked a bit, leaked a
lot, but it did run.  Unlike the dozen or so O-12s I already have.

After I got it home, I put in some more gas and ran it around the yard for
a few days.  It's a hand clutch, foot brake model with the tiny 6" front
wheels.  Clutch works like a Caterpillar, not a John Deere.  Back is
engaged, forward is disengaged.  Not a speck of paint on the tractor, but
it started easily.  Needed some odds and ends.

A week or so after I got it home, the fan belt broke.  I didn't notice it
and made another lap around my property before I parked it.  Smelled a
little warm and steamed a bit, but that was all.  Next weekend I removed
the fan, which looked a little funny (it had come loose, as it turns out).
 Fans are one of those things that never get serviced on the -12 family;
they have an oil reservoir that needs to be topped off.  While servicing
the fan I found a cracked blade, so I replaced it with a unit I had
already sandblasted and painted.  Thought I had a fan belt, but it was 39
inches long; used all the belt adjustment and more.  Turns out that a 37"
belt is nearly perfect.  36 1/2 would be even better, if you can find one.
 It's a wide belt, so at NAPA, it's a '370W', or something like that.

Had to remove the starting crank in order to make room for the belt.  In
order to get to that, you have to remove the flat sheet of metal that
covers the front of the frame below the radiator.  The cast iron support
for the starting crank was broken, so I went looking for a better one on
my other O-12s.  Seems that they've ALL been broken.  Probably by people
trying to push something with the front of the tractor.  So the problem
changed; I had to decide whether to make a new crank support or try and
get an old one rewelded.  At present, I'm leaning toward fabricating new
crank supports out of steel.  Some people can weld or braze cast iron
successfully, but for every one of them there are a hundred people who
think they can (and are wrong).  Only about a quarter inch of the crank
support shows, so I think that a fabricated unit will work fine and be
undetectable by casual observers.  And give me some quality time on the
lathe makin' parts.  If I do go that way, I'll make up a lot of crank
support, not just one for this project.

I found a usable but ugly crank support, replaced the fan belt and fan
assembly and fan shroud, and got the tractor running again.  Decided to
check the air filter; nearly every old tractor I've bought comes with an
empty oil cup.  This one was full of oil, but badly dented, so I found a
better replacement and filled it with fresh oil.  The hoses that attach
the right angle air pipe to the carb needed refreshing; I used 303
protectant.  The magneto was working well, but I am nervous about running
F4 magnetos that obviously haven't been serviced for thirty years, so I
pulled the old mag and put on one I had rebuilt.  Plug wires and spark
plugs will need checking before too much longer, but that's not urgent.

Fiddled with front tires.  They were very low.  The 6" front wheels
require extensions on the valve stems in order to get them out where you
can add air.  I put two extensions together and got the tires filled, but
one goes flat over night for reasons I haven't determined yet.  Rear tires
just needed filling.  And the brakes drag badly; I can't push the tractor
by hand.

The more I drove the tractor, the better it ran, and the worse the
radiator leaked.  I'm going to try a stop-leak fix first; rebuilding O-12
radiators is a major task.  And the overflow pipe has rusted away, so any
overflow drips down, gets sucked into the ran, and blows back onto me. 
That, also, will require radiator rebuild to fix.

The fuel pump glass bowl had a water line in it, so I pulled it off and
cleaned the glass.  Just marks from dirty fuel; the fresh fuel I had put
in had no water in it.  Had to scrounge a new gasket for the sight glass;
the old one was shot.  I started the tractor and saw fuel dripping from
the fuel pump.  And noticed that someone had replaced the fuel pump vent
with a pipe plug.  That's bad; it means that if the pump diaphragm is
broken, fuel runs right into the crankcase.  So I replaced the fuel pump
with one I had rebuilt.  The fuel line from pump to the 'T' by the gas
tank had a badly messed up fitting, so I scrounged in my shop for a better
line.  Found one and installed it.  Tried to start the tractor and it
would only pop after I sprayed carb cleaner in the carb.  Unscrewed the
end of the 'new' line I had installed and found it dry.  No fuel was
passing.  Took it off the tractor and found that it was completely
plugged, so I put the old, ugly line back on.  The O-12 started and ran
well, so I drove it around and enjoyed it.  No smoke, crisp throttle
response, etc.

Pulled it back under my sun shade and drained the oil.  Black, and smelled
of gasoline.  Removed the oil filter cover.  The filter was one of those
Purolator brass sieves.  Unscrewed the plug in the base of the oil filter
bracket, and nothing came out.  Poked my finger in.  It was full of
'Jello'; sludge which was too thick to drain.  Stirred it up with a
screwdriver and let it drain overnight.  Today I removed the cover plate
and cleaned out the 'sludge trap'.  My term; I've found it full of goop on
every F-12 I've dismantled.  Sludge falls off the filter element and drops
down into the sludge trap.  Nobody ever cleans it.

Since I was into sludge cleanup, I removed the rocker arm cover today and
hosed down the rocker arms and valves with Wal Mart carb cleaner, then
blew the sludge off with compressed air.  Cleaned up the oil filter
bracket and installed a new gasket.  Tried a repainted oil filter cover on
for size and found that it rocked side to side at least a sixteenth of an
inch.  No way it would seal.  Looked closer and saw that the oil filter
bracket was damaged, as all X-12 units are; bent downward and cracked from
being overtightened to stop leaks.  Since ALL oil filter mounts are bent,
I'll have to root through the ones I've already cleaned up and find the
least distorted one.  Then I'll have to fill the O-ring groove with JB
Weld, mount it on my rotary table and mill out a new groove with a 1/8"
end mill.

Once I get the filter mount back in place, I'll put in the old brass
filter element and fill the crankcase up over the crankshaft with diesel
fuel.  Then I'll remove the spark plugs and tow the tractor around the
yard in gear so that the inside of the engine gets washed out.  Then I'll
drain the diesel fuel and drop the oil pan (no easy task on an early O-12;
this one has the Y-shaped radius yoke under it, which interferes with oil
pan removal.  Then I'll clean out the pan, clean up the oil filter intake,
and install new oil pan gaskets.  After all of that, I'll fill the
crankcase with good oil, confident that 90% of the sludge buildup is gone.

And after that, I'll drive the tractor around and then adjust the valve
lash.  And take care of a few more odds and ends.  Hopefully I can stop at
that point, with a good-running but ugly O-12.  And get back on the O-12
restoration I'm just a little ways into....  still rebuilding the front
axle and steering parts.

-Karl