Farmall M in the suburbs

Farmall M



Life being unpredictable, I decided one day in late summer 2006 to buy an M Farmall and keep it in my garage.
1948 Case VAH, August 2006I've long enjoyed browsing eBay auctions and photo ads for various tractors, just to keep in touch with what they're selling for and to daydream about them, but didn't have any clear intention of buying one just yet.  I'd only just recently reacquired the 1948 Case VAH (right) that I'd grown up with, having bought it back from the neighbor my dad had sold it to about 20 years earlier.  Dad was glad to see it again and happy to let me keep it in his barn, and I'm happy to have not let it slip away, and one old tractor for a suburban office-worker like me might ought to have been enough.  (Yes, it's green, but that's a story for another time).
But the Case is up at the farm, where I visit less often than I'd like, and some other sides of life were making me long for a touchstone here at home.  When I ran across a genuinely lovely 1940 Farmall M on eBay, stuck but clean and original, practicality and budgets gave way to daydreams of patiently freeing up the stuck pistons over the course of time in my garage.  The bad news was that the tractor was located an inconvenient number of states away, and with several hundred dollars in transport costs the delivered price started to look pretty high.  Fortunately enough for me, somebody else wanted it pretty badly also and bid just one more time.
1950 Farmall M, August 29 2006 So I let that one go, but having convinced myself I could have an M in the garage I resolved to find one closer to home.  A short while later I was looking at a picture on of this 1950 M about 25 miles away from me, and somewhere I'm sure a soprano started warming up to sing.  It took a week or two to arrange to get over to see it, but I remembered to bring my checkbook with me.  This one doesn't have the pristine originality of the one I'd seen on eBay but it's a smooth-running easy-starting old girl, and it was close, and that was enough.
Once in a while I drive it down to the corner gas station to put air in the front tires, or just take it for a spin and enjoy the sound of the engine and the waves of the neighbors.  Some year I still hope to get back out in the country where I can put the M to work.  In the meantime, seeing this handsome machine in my garage warms my heart every day.  And it's hard to beat the satisfaction of fixing up an honorable veteran like this.  I'm not out for show-quality restoration but I want the tractor to look decent and be solid mechanically, and I've already enjoyed many hours slowly tinkering and learning.
  Old wiring The electrical system was one of the first tasks:  All the ignition and lighting circuit wiring was pretty much shot and the charging system didn't work.  Replacing the wiring sounded simple enough when I got started, but I eventually figured out that just putting new wires where the old ones had been wasn't going to cut it.  I couldn't match the existing wiring up to the diagrams in the parts book, and there was no existing wiring at all connected to the generator.
The generator had a voltage regulator mounted on top of it, but the tractor had evidently started life with a cutout relay instead.  A cutout relay lets current flow from the generator to the battery but prevents it from going the other way, so you can charge the battery up but it won't just drain back down through the generator.  The tractor operator controls the charging rate with the light switch, which has four positions:  High, Low, Dim, and Bright.  If the lights are on (Dim or Bright), the generator charges the battery at the high rate.  If the lights are off, the generator charges at either the high or low rate depending on the switch position.  Too little charging and the battery will run down; too much and the battery can be damaged.  An automatic voltage regulator has the same basic job as the cutout relay, letting current flow from the battery to the generator but not the other way around, but it also solves the under- or over-charging problem.  It lets current flow from the generator to the battery whenever the battery voltage is lower than it ought to be, but then stops as soon as the battery is charged back up.
With a regulator there's no need for the operator to manually control the charging rate, so the wiring between the switch and the regulator is a little different than it would be for a cutout relay.  And there's no need for the High and Low positions on the light switch.  (On tractors that came equipped from the factory with a voltage regulator, the switch was truly just a light switch, and had only three positions:  Off, Dim, and Bright).  My tractor still had the four-position switch.
Not really understanding all this at the time, I ran new wires to the regulator and hooked them up the way you should for a tractor with a regulator, and then hooked up the other ends of the wires to the switch the way you should for a tractor with a cutout relay.  That had the unfortunate effect of creating a direct short to ground, which made some wires get really hot and made me re-think just how smart a mechanic I was.  With the generous help of several folks on the ATIS e-mail lists, and with Robert Melville's Farmall wiring diagrams, I disconnected the High/Low part of the light switch and wired the rest of it as if it were a three-position switch, and all was well.
Original switch wiring Rewired switch

Before-and-after photos of the switch box and the voltage regulator wiring.  I replaced the ammeter while I had the switch box apart, with a nice original-looking replacement from OEM Tractor Parts.

Original regulator wiring Rewired regulator
October 2006

Posing in the back yard on a nice October afternoon, after a trip up to Anderson Tractor Supply in Bluffton, Ohio to buy a set of fenders and the belt pulley.  I'd gone to Anderson's about ten years earlier to look for fenders for the Super M I used to have, and had good memories of wandering around their salvage yard.  I'd found that first set on what was left of a Farmall 400.  The ones I found for this tractor were on a 560, although they're just normal H and M fenders.  Anderson's had another set with much nicer paint, but I didn't want the fenders to be the nicest-looking part on the tractor--weathered but straight suits me just fine.

Saturday afternoon, time to work on the tractor for a while.  I put on an M&W aftermarket throttle lever because that's what had been on my old Super M, and I like to stay with things that work.  The steering wheel made my hands all black and sooty every time I touched it, so I painted it with clear spray-on lacquer.  Looks fine and worked like a charm.  


Miscellaneous odds and ends:  The generator had been tilted forward a little bit when I bought the tractor, and I soon found out why:  one of the mounting bolts had broken.  The remnant of the bolt came out pretty easily after drilling it and turning in a screw extractor.  An after-market PTO lever had been added, but in the interest of cleaning the tractor up I took it off.  (And in the interest of slightly reducing the cost of tinkering with this old machine, I sold the lever on eBay for $37.56).  The drawbar told a story of long use:  worn, and repaired, and worn again.  I replaced the drawbar and hitch with another set, not new but much less worn.  That took some effort and big wrenches, and patience.

Broken generator mounting bolt Aftermarket PTO lever Worn drawbar
Battery cables

One day while trying to start the tractor I noticed a puff of smoke from down by the starter switch.  When I tried again one of the mounting bolts on the side of the switch glowed red-hot.  Those are rarely good signs.  So I pulled the battery out and took all the cables off and removed the switch, and carefully opened it up.  The cardstock insulation around one of the terminal posts had worn through, letting the post touch the metal switch housing and thereby creating a direct short to ground when I pressed the contact button.  I had some polystyrene sheet left over from some model-making, and it looked about the same thickness as the worn-out cardstock, so with an X-Acto knife and a hand drill and some plastic cement I made a new insulator.  Put the switch back together, put it back on the tractor, and it starts like a champ again.  Have to love these forgiving old machines.

Starter switch repair

Starter switch reassembly

I knew when I bought the tractor that the power take-off didn't work:  The shaft rotated freely but I couldn't engage it--the PTO lever would barely move.  I removed the control rod and the PTO guard and cleaned up the outside of the PTO housing so I could see it better, but (not knowing what to look for) I didn't see anything wrong.  Removing the PTO meant draining the transmission oil first, which of course was a project in itself:  The operator's manual says to put 13 gallons of oil in the transmission, but I drained about 18.  First few gallons were kind of brown and frothy, so some water seems to have gotten in at some point.  The rest didn't look as bad as I'd expected, although there was a bunch of goopy sludge left in there that I had to clean out through the rear opening while I had the PTO housing off.  Aside from that bit of sludge at the bottom, everything in the transmission case looks great.
PTO Transmission oil

Draining the transmission oil

Inside the rear case  
PTO assembly Removing the PTO was easy, just a matter of removing the bolts and pulling the whole assembly out.

All five of the bolts turned out to be different, so I made some notes to help me remember how to put it back together later.


PTO mounting bolts

Looking into the PTO housing, I could see that the shifter linkage did in fact move, but not far enough:  Pulling up on the external shifter lever rotated the internal shifter arm, but not all the way to the "engaged" position, so the sliding PTO tube didn't go far enough forward to engage the transmission countershaft.  The external shifter lever only had a range of motion of about 15 degrees, and about five of those degrees were free play (didn't move the shifter arm at all).  I decided those five degrees of slop meant there had to be a lot of wear on the shaft between the external shifter lever and the internal shifter arm, wasting a lot of its range of motion.

I wasn't sure I had the skill to fix worn-out steel components, so I made another trip to Anderson's and picked up a replacement PTO assembly.  This photo shows the difference:  With the external shifter lever all the way up, the internal shifter arm is all the way forward in the "engaged" position, so the little spring-loaded bullet-shaped poppet coming in from the right side has snapped into the rear detent on the shifter arm.  In the photo above, of the original PTO assembly, the shifter arm isn't far enough forward for the rear detent to have reached the poppet.

The end of the PTO shaft on the replacement assembly is in pretty good condition and the bearing looks fine.  I had the local Case/IH dealer replace the oil seals on general principle... the original PTO had leaked a little bit of oil there, which turns into a big mess surprisingly quickly.  I don't know if this one would have leaked or not, but replacing the seals and gasket while I had it out of the tractor seemed like pretty easy insurance.

  Trying to reassemble it PTO partially disassembled PTO shift lever and arm PTO shift lever and arm

Meanwhile, I wanted to see if I could get the shifter linkage out of the original assembly, to at least look at the parts which were worn out and to see what might still be worthwhile to take to a swapmeet.  There's only one bolt that needs to be removed in order to get the shifter parts out of there, but removing that bolt took some trial and error--it's a bit too long to come out without bumping into the underside of the cam on the shifter arm, and the collar on the sliding PTO tube is in the way.  I eventually got it out by randomly wiggling and pulling and shaking.  (Getting it back together later tested my patience and vocabularly, but I felt like the king of the world when it finally dropped back into place).

With the linkage parts out where I could see them, there was very little visible wear.  The shifter arm is fastened to the shifter lever shaft by the above-mentioned bolt.  The bolt itself wasn't worn out of shape, and the hole in the shaft through which the bolt passes wasn't distorted into an oval.  It all fit together fairly snugly with only a little bit of slop (the five degrees or so of wiggle that I'd noticed earlier), and given the size of the bolt and the diameter of the hole it didn't seem as if anything could have been much different when it was new.  So I checked the shifter lever on the other PTO assembly, and sure enough it has four degrees of free play.  So why didn't the original one work?

After scratching my head for a while, I finally noticed the obvious problem:  The shifter lever had been broken and re-welded to the shaft at some point, but at the wrong angle.  In the picture on the right, above, you can see the weld and the angle at which the shifter arm is leaning to the right.  With the shifter lever horizontal, that arm ought to be vertical.  Since the arm is leaning back, it can't come far enough forward to mesh the sliding PTO tube with the transmission countershaft before the shifter lever hits the stop.

PTO comparison

This picture of the replacement PTO assembly in front of the original one shows the problem.  Both are in the "disengaged" position, with the shifter levers down as far as they will go.  The lever in front can rotate almost 30 degrees counter-clockwise before it hits the stop, but the one in back is already halfway "up" so it only has half that range of motion left.

I put the replacement PTO on my tractor, but still need to figure out what to do with the old one.  Cutting a little notch in the shifter lever, so it can rotate farther before it hits the stop, seems like it'd work but it'd be kind of a hack job.  Better to really fix the angle at which the lever is welded to the shaft, but that's beyond my skill and equipment.  Might put a tag on it explaining what's wrong and bring it to the swapmeet at Portland...

Old gasket cleaned off New gasket sprayed with Permatex Ready to reinstall Back in operation  

I used an old putty knife to slowly scrape the old gasket off the mounting flange on the rear of the transmission case, then sprayed on some gasket sealant.  The inside face of the PTO housing got some also, and both sides of the new gasket, then it was time to put it all back together.  That PTO assembly feels pretty heavy when 95% of the shaft is wobbling around inside the tractor and all you have to hold onto is the housing and outside end of the shaft, but it's great when it fits into place.  With everything reassembled and the transmission case refilled with oil, I gave the PTO a test run in the garage and it all looks good.  I'll watch to see if it leaks over time, but for now I think this job is finished.

Oily brake drum Oil leaking past the seal Pulling the old seal Brake shaft and bearing  
Cleaned up New oil seal in place

Reinstalling the brake

Reassembled brake  

Next job after getting the PTO back together was to clean the brakes up, both of which were pretty gunked up with oil which had leaked past the seals.  Getting them apart was straightforward except for actually removing the old oil seals--I had to buy a gear puller (which seemed like a good tool to have anyway).  I used some wood blocks and a piece of old angle iron for the puller to push against, since it didn't seem right to let it push hard against the brake shaft itself.  And hard is the right word--the puller bent the heck out of that piece of angle iron, but eventually the seals came out.  I bought new seals from Case/IH ($17.70 each, plus $2.50 for the little cork washers that go behind the big bolt that holds the brake drum onto the shaft), and carefully tapped them in place with a hammer and block of wood.  I cleaned everything else up using rags and a little gasoline, and a propane torch to boil some remaining gunk out of the brake bands.  Put it all back together, adjusted the brake linkages the way the operator's manual said to, and they work a lot better now than before.  Plus there are two fewer sources of oil drips on my garage floor.


Repacking grease in the front wheel bearings turned into a big job, like they all seem to do.  First task was to build a stand for the front end, and fortunately I had some salvaged 4x4s and plywood on hand.  Once I had the wheels apart and the axles cleaned up so I could compare them to the parts book, I realized that neither wheel had the grease retaining seals that are supposed to go up next to the bearings.  And the castle nut on the right side had the threads all worn down somehow so it wouldn't tighten up (beats me how the threads on the inside of a nut get worn down).  But those things are all still available from the CaseIH parts counter, so after another $46 I was ready to go.

Repacking the front bearings Front axle Reassembling the front wheels

Only trouble was, by then I'd noticed how worn and dry-rotted the old tires were.  In hindsight I might have paid more attention to all this stuff when I bought the tractor, but it's still satisfying and educational and fun to gradually bring this old tractor back into shape.  I celebrated having new tires and repacked bearings by taking a quick drive around the neighborhood.

Hydraulic control rodsI bought this shiny red pair of hydraulic control rods because I needed the one with the bends in it, which controls the valve for the remote cylinder.  The straight one controls the Lift-All pump, but I already had one of those on the tractor and a second one that I'd bought sight unseen because I mistakenly thought it was the other type.  I didn't want yet another straight rod, but the bent ones are hard to come by.

When I had them side by side, I could see that the rods themselves were the same length.  Since I had a spare straight rod, I cut off the little stop peg and bent the rod to match the other one.  It's not 100% identical to the genuine rod, but it's mighty close--that's it in the pictures, after I painted it with primer.  It was fun making what I thought was a useless extra rod into the part I needed, and afterwards I re-sold those shiny red ones.
Hydraulic control rods

Same deal with the support bracket for the remote valve rod.  I bought this arm to get the extra little bracket that clamps onto the end, but once I looked at it I figured I could make one to do the job well enough.  I had some sheet metal left over from working on the grille (below) and cut it and bent it to be a reasonable approximation of the original, put it on my tractor, then sold the other arm and bracket.  Didn't quite get all my money back, but it was pretty close.

Control rod support Control rod supports
Grill patch and insert Inside Outside

The grille had been missing the insert panel, as is often the case with these old Hs and Ms, but the sheet metal below the insert opening had also been cut out.  I had a replacement insert from OEM, and made this little patch from a piece of flat steel I'd bought at the hardware store.  I took the whole thing to an auto shop and had it welded together, then used some auto body filler, primer, and paint to make it look fairly respectable.  The grille could still use some touch-up straightening and the whole tractor will need a paint job some year, but I'm happy with it for now--it sure beats that big open hole that used to be there.

  Tractor back together Finished grille

August 2006

June 2007

October 2007

November 2008

January 2009


I hadn't intended to ever sell the M, but one day I noticed a photo ad for another tractor... a late 1953 Super M, very much like the one I'd owned a dozen years ago only even nicer, and as soon as I saw the ad I knew I was done for.  Just like that one I'd had before, this new Super M has the transitional grille, sort of halfway between the regular M/Super M grille and the Super MTA grille.  Those grilles apparently only showed up on the very late production Super Ms, as tooling was gearing up for the Super MTAs.  I've often wished I'd hung onto that other Super M and had never seen another just like it in the dozen years since I let it go... so when this one came along I didn't lose any sleep over buying it.  For a brief and enjoyable period of time I had two tractors here in the suburbs, but I reluctantly sold the M to make room in the garage and my checkbook for the new Super M.  Now this one, I definitely plan to hang onto for the long haul.


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Copyright notice:  Unless noted otherwise, I wrote all the text and took all the photos.  Feel free to make any personal use of them, but do not make any commercial or public use of them without my specific okay.