Manufactured between 1941 and 1952
IN THE SHOP with Rachel
The Farmall M is one of my favorite tractors. It is popular for a reason: it’s reliable, easy to find parts for and fun to drive. The Farmall M Diesel is a bit more difficult to repair but has one significant advantage: fuel economy.
The Farmall MD was manufactured from 1941 to 1952. These early Farmall tractors (called the "letter series" by enthusiasts) used initials to indicate variants on the main model. In addition to the MD, standard M Farmall variations include the MV (high crop) and MVD (diesel-fueled high crop).
Farmall's inventive gas-over-diesel starting system was used in the MD (as well as many other models). Operators started the tractor on gasoline fuel (a lever adjusted the compression and got the spark plugs firing), then switched over to diesel once the engine was warm.
This system can be tricky to repair. Here are two reasons why:
The first reason is the number of systems. Two fueling systems (one for the gasoline, one for the diesel) give it twice as many things that can go wrong. A clever system like this requires an equally clever mechanic! Compared to similar tractors, there are far more "mission critical" systems to keep in working order.
The second reason why this tractor is difficult to repair is the lack of parts interchangeability. Normally, Farmall did a great job at using the same or similar parts across models. The laws of supply and demand work in your favor - with so many tractors using the same parts, they become easier to find and less expensive. That's not the case with some of the parts on this tractor - most notably the carburetor. Its unique design wasn't used on any other Farmall tractors, making it difficult to service. The injection pump is similarly unique. Even the distributor has a reverse rotation! Parts can be hard to find.
The HUGE advantage of the M Diesel is the fuel efficiency. Compared to other tractors in this size range, the M Diesel really excels in conserving fuel. My friend's uncle purchased one of these tractors new in 1959 to use as a power plant for his sawmill in northern Michigan. For 15 years, the tractor ran the sawmill (with power to spare) on just 8 gallons of fuel a day. What a workhorse!
While this might not be the best tractor for an inexperienced DIY mechanic, you can't beat the power for the price.