[Farmall] Another O-12 project, part 6

[Karl Olmstead]

Spent one day last weekend putting a new woodstove in the shop, an airtight.  Takes longer to get going, but now the shop only gets smokey when I have the stove door open, adding wood.  Major improvement over the leaky potbelly.  Kept the shop toasty warm today.

I always remove the radiator hose fittings from F-12 type tractors, both on the radiator and the engine.  That lets me clean some of the rust out of the engine, and repair the rust damage on the fittings.  I knock off the worst of the rust with the needle scaler, then sandblast the fittings.  Last Sunday and today (Friday) I filled in the corrosion pits with PC-7, a filled epoxy from Ace Hardware.  Very similar to JB Weld, but thicker so it doesn't slump as much.  After the PC-7 cured, I filed and ground it off flat so that radiator hoses and the gaskets between hose fittings and engine block would seal properly.   I puttied up the bottom radiator tank flange also.  I use RTV sealants on the radiator flanges, but rebuilding the flanges guarantees success.

I've talked before about 'batching' my restoration projects.  After I finished with radiator fittings today, I started rebuilding F-12 fuel pumps.  Or at least dismantling them.  Broke down ten of them and got most of the top and bottom housings sandblasted.  Looks like I have four or five rebuild kits on hand; I'll need to get more.  But the most important thing is to 'batch' the painting.  Modern paints are too expensive to waste, so I like to accumulate a LOT of clean parts before I prime them.

After I finish prepping the fuel pumps, I'll start on magnetos and carburetors.  Same procedure; tear down five to ten of 'em and get the parts ready for painting.  Once the painting is finished, rebuilding takes very little time.  Being able to grab a rebuilt carb or mag or fuel pump off the shelf when I need one to get a tractor running is an incredibly nice feeling.  New carb/mag/fuel pump plus new plugs and wires will breathe new life into almost any tractor.

For folks who haven't followed my F-12 and O-12 adventures, I think it might be time to review what I feel is needed to get one running reliably.   As mentioned above, the fuel system is always in bad shape.  The fuel pump needs rebuilding.  Until it is working properly, you can hand crank the tractor forever and it won't start.  The hand crank mechanism is usually worn out and needs to be fixed.  On 'regular' -12 tractors (O-12, W-12, etc.), the hand crank bushing is always broken and needs to be repaired.  The dog that engages the pin in the nose of the crankshaft probably needs to be reshaped with an angle grinder so that it grabs the pin securely.

The carburetor needs to be rebuilt.  F-12s always run rich until carb is functioning properly.  The spark plugs need cleaning and regapping, or replacement.  The plug wires are shot.  The air cleaner oil needs changing, and the rust holes in the bottom of the oil cup patched.  The oil filter needs cleaning or changing, and the oil filter bracket needs to be rebuilt; it is deformed downward on the outside edge due to over-tightening.  The engine oil pan needs to be removed and de-sludged.  Ditto the oil filter inlet screen.  Be sure and replace the rather complicated oil pan gasket.

The magneto bearings are dry and need to be lubricated.  The point gap is probably too small.  The magnets need recharging.   The timing is usually off.  The valve rocker arms need adjustment.  The feet may be broken off the middle rocker arm shaft support.  The radiator cooling fan bearing needs to be oiled, and the fan belt changed.  The fan belt adjustment screw needs to be freed up.  The rubber fittings on the air cleaner pipe need replacement, as do the top and bottom radiator hoses.

Farmers who used -12 tractors couldn't afford antifreeze, so the cooling system is severely corroded.  The bottom radiator tank is full of rust, maybe even rusted through.  All flanges are in bad shape and need rebuilding.  The radiator core needs to be rodded out.  Most of the passages are clogged with rust.  The overflow tube is usually rusted off or clogged.

The front motor mount assembly is in rough shape.  The cast 'basket' is usually broken, and often stuck to the forged piece that attaches to the tractor frame.

I think that's about it for the engine.  Moving back, the transmission lube has never been changed, the brakes may be frozen up, the steering gearbox needs adjustment and cleaning, and the countershaft seals are shot so transmission lube leaks around the brake shafts.

And that's on a GOOD -12 series tractor!

-Karl

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