[Farmall] Another O-12 project, part 3

[Karl Olmstead]

Today was very rainy and cold.  It even snowed for an hour or so.  My cheap woodstove leaks so much smoke that I decided not use it.  I fired up a 'Mr. Heater' on propane instead.  It keeps the air clear in my shop, but it only heats about a 10 foot square.  The woodstove heats the whole 30x60 shop,  but I can't breathe for the first hour or so.

I had piled most of the O-12 parts needing rebuilding on my workbench.  Decided to tackle the radiator first because it took up so much space.  Pulled the bottom radiator tank first, because they are ALWAYS full of rust on -12 tractors.  This one was no exception.  It was packed full of large rust plates, all the way up to the radiator core.  Looked almost like leaves, the plates were so large.  Since the bottom tank was so bad, I removed the top tank also.  Held the radiator core up to the light, and maybe one tube in ten was clear.  Definitely time for cleanout.  Added the parts to my project pile.  By the way, I've found that a needle scaler works extremely well on the castings.  Knocks off the rust much faster than sandblasting.  Wire brush works best on the flanges of the brass core, with a slender bar to ram stuff out of the tubes.  Sandblasting distorts the soft brass flanges too much.

Scrounged up my box of fuel pumps and parts, but didn't get around to dismantling the old pump.  I think I still have two or three rebuild kits from Rice, so that shouldn't be a big deal.  Re-doing the butchered plumbing will be a lot of work.  Might be time to invest in some new parts.

The other problem needing attention was the front motor mount assembly, as I discussed yesterday.   Overnight soaking with Kroil hadn't done anything, so I decided to use heat.  Set the forged part on some 2x4's so that the casting was unsupported, and applied heat from an oxyacetylene torch.  When the forging was fairly warm, I found a big socket that fit inside the forging and pressed on the front of the casting.  Pounded away with a dead-blow hammer.  To my surprise, the parts moved a little bit, a sixteenth of an inch or so.  Further pounding did no good, and neither did my hydraulic press.  Heated the forging up again, and got almost an eighth of an inch of progress.  After that, I was able to press the casting out of the forging.  My first success on stuck motor mounts!  Incidentally, if you're having difficulty envisioning these parts, the cast iron 'basket' has a cylindrical extension that slides into the forged crosspiece.  I was pounding and pressing on the extension, so that the casting would always be in compression.  Cast iron is very strong in compression, but weak in tension.  So inserting pry bars between the two parts is a bad idea.  I've proven that.  Incidentally, after sitting overnight with Kroil on both sides of the joint, the mating surfaces were bone dry when I got them apart.  Once rust expands and fills up all the available space, there's no way that penetrating oil can get in.

Penetrating oils may help, but heat is enormously more effective.  I twisted off one bolt in the top radiator casting, so I cleaned up around it with the needle scaler and then heated the bolt red-hot with the torch.  Grabbed the protuding stub with my Vise Grips and began wiggling it back and forth.  Just a little, not enough to twist it off.  Not much progress at first, but then I felt a tiny bit of motion.  Kept working at it, and dripped a little oil on the area where the bolt disappeared into the casting.  After five minutes of back and forth, the remainder of the bolt unscrewed cleanly.

By that time, my feet were cold and the shop was even more flooded than when I started, so I decided to call it a day.  Besides, the motor mount was the last really BIG problem on this project, I think.  Now it's just a lot of sandblasting, retapping bolt holes, and painting parts.  I've actually only completed two items; the crankshaft nose and the hand starting crank.  So there's plenty of fun left.

Electrolysis is a very powerful tool for the restorer.  But in order to work, the liquid needs to be able to penetrate the joint, and electrons need to flow from the electrolyte to the rusted metal.  I'm not convinced that electrolysis will do much for two parts rusted tightly together.  It'd be a great way to remove the rust from the top and bottom radiator tanks, now that I have them apart.

It's hard to know how to cope with a fellow you know is a butcher of antique iron.  On the one hand, he's a really nice guy.  On the other hand, everything he touches turns to used food.  The more I think about it, the more I believe that he realized what a mess he had made, and he decided to pawn it off on me.  But, he sold me two O-12s, one running and one not stuck, for less than I usually pay for a stuck one!  I don't feel badly about the transaction, just amazed at what I found.

-Karl