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Ford Tractor Tune-Up and Maintenance

All N-Series Tractors - Ford-Ferguson 9N, 2N, and Ford 8N

Most of these old tractors that are offered for sale have been neglected for several years before the owner decided (or was convinced) to sell. Even if you have purchased a "restored" tractor, it takes very little time to go through the various systems. No engine can perform well without properly maintained Fuel, Air, and Ignition systems. When was the oil last changed? Does the engine have good compression? The hydraulic system needs a clean sump with the proper type fluid. Other items, such as brakes, clutch, and steering, often need some work.

The best source of maintenance and repair information is the original Ford tractor Owner's Manual and the I&T FO-4 Shop Manual. Reprints or even originals of both are surprisingly inexpensive and very easy to get. The information I have provided on this website is intended to supplement, not replace what is in the manuals. Warning: A single step like "remove bolt" can sometimes take half a day or more to accomplish. The best manuals are written while actually taking the vehicle apart, but they are always taking apart a new vehicle. Very few step-by-step procedures can include many of the real-world steps that deal with layers of gook, rust, stripped threads, frozen fittings, and previous hack-job repairs. I will attempt to fill in some of the blanks.


If you are attempting to bring a basket-case back to life, if your tractor hasn't run in years, is years behind on maintenance, or has been involved in some horrible weather event (like power washing), PLEASE don't just hook up a battery and start grinding the starter. That's a good way to destroy an engine that might have been ok. Remove the spark plugs. Keep them lined up so you know which cylinder each came out of. Look at them. Are they all the same? Search for "Reading Spark Plugs" on the web to find much more info than I have space for here. Pour a little Automatic Transmission Fluid (ATF) in each cylinder. Use about an ounce or so in each cylinder. Just enough to wet the rings. Any brand any type ATF is good for this.

If you have no idea about engine condition, check and see if the engine is locked-up. Will it turn by hand? Grab the fan belt and see if you can turn the engine just a bit. The engine should turn fairly easy with the plugs out. If you can move it by hand, twist each spark plug back in a couple of turns to keep trash and bugs out of the cylinders. Let the ATF work in the cylinders for at least 30 minutes. Several hours is even better.

While the ATF is soaking-in, check the oil. If it looks bad, or the engine has been sitting for several years, change the oil and filter. If all seems ok so far, remove the plugs and wet the cylinders with ATF again. Leave the spark plugs out and crank the engine. Listen for the compression strokes and for any expensive noises. If all is well, check for oil pressure on the gauge. Now would be a good time to run a compression check.


You should have heard the cylinders go WUFF, WUFF, WUFF, WUFF out the spark plug holes, in sequence, while cranking. You could use your finger, but a compression gauge is a lot more accurate. Place over each spark plug hole and record the max compression for each. Once again, if you search for "compression check" you will find a lot more info than I can put here. Anything above 90 PSI is good and the cylinders should give an equal reading, within about 10%, or so. It's a tractor, not a dragster, so don't get too excited if a cylinder is a little low. If one or more cylinders is way low, you may have broken rings or stuck valves. This needs to be fixed before we go any further.

If you are still with me, it's time to check for fuel and spark. Service the distributor and make sure you have good spark. Install a fresh set of spark plugs, and crank it up. If it starts, treat it like a fresh rebuild for at least the first few minutes. Check my break-in procedure HERE


So, you hear a tapping, banging, squealing, or other noise but cannot pinpoint exactly where it is coming from. Before doing any WORK on the vehicle in question, here is a quick way to find out where the noise is coming from. Some people have those mechanics stethescopes. The same type of thing the doctor uses to listen to your heart. Any long-handled tool will work much the same way as that fancy steth thingy. I often use a long screwdriver to locate the source of odd noises. ALWAYS BE CAREFUL AROUND RUNNING MACHINERY! Hold the end of the screwdriver blade on your generator, water pump, governor, and various locations on the engine block. At each location, rest the handle against your ear. You will be able to quickly pinpoint exactly where the noise is coming from. BE CAREFUL! Don't get that screwdriver or any part of your body tangled up in the fan belt, other moving parts, or exposed electrical terminals. You could buy a real mechanics stethoscope, but why spend money if any long screwdriver, broom handle, or similar object will accomplish the same thing for free?


The N-series tractor Owner's Manuals say to use straight 30-weight motor oil when the temperature is above 90-degrees, 20-weight for all temperatures between 10 and 90 degrees F, and 10-weight for temperatures between minus 10 and plus 10. Modern multi-Grade, high-detergent oils did not exist when those specifications were written. The oil sump and pickup were designed to allow dirt and sludge to collect in the bottom of the sump. That was normal for the non-detergent type oil that was commonly used. Modern Multi-Grade detergent oil has been engineered to keep dirt in suspension, so the filter can collect more, and what remains in suspension comes out more easily when you drain the old oil. With reasonably frequent oil changes, this essentially eliminates the need to flush and clean the sump before adding new oil.
Since the lightest weight oil Ford recommended was 10-weight, I normall look for a 10-40 or 15-40 multi-grade for year-round operation in Central Virginia.

The ZDDP controversy:

What follows are some of the facts and circumstantial evidence being circulated by both sides of this issue. Draw your own conclusions.

I will continue to study this issue and update this article as needed.

In an attempt to find something with additives most appropriate for my tractor engines, have used some of the "off-road" and "racing" motor oils. Unfortunately, some racing oils do not have sufficient anti-corrosion additives for engines that sit for long periods. Racing oils may also be formulated with the assumption they will be changed much more frequently than I plan to change oil in my tractors. A few "Classic Car" motor oils have begun to appear. Their advertising sounds good. If true, some of these "classic car" engine oil products could be the best choice for our engines. I'm keeping an eye on products by Lucas Oil, Castrol, COMP Cams, and Mobil 1.
Located in Central Virginia, we have a fairly mild climate with temps that only occasionally into the single digits. I'm not going to be using any of my tractors in those conditions. I'm going to be as close as I can get to a fully-loaded wood stove. We do get some spells when temps can stay below freezing for a few days, so I look for a multigrade, 10W-40 or 15W-40. I feel the modern multigrades provides the best year-round protection.

For rebuilt engines, use an assembly lube with high levels of ZDDP. Change motor oil soon after initial break-in to remove assembly lube and anything else that may have been in the engine. Change motor oil again at the first sign of "color" to flush anything else that may be in there.


There is nothing inherently wrong with the canister type oil filter. New filter elements and gaskets are still available for it. Don't forget the gasket that goes under the head of the bolt on top! What a mess that makes when it's cracked or left out! There is a novelty to changing just the filter element. However, the spin-on type filters are a lot less messy, and more convenient. I just converted my 8N to the spin-on type filter. I have been seeing the conversion on ebay for the last few years, and finally broke down and bought one. This is a direct replacement, and hooks up using the original oil lines. I did remove my oil lines and use a tubing bender to re-shape them. The instructions said to connect the lines to the new filter base, and use the new part to force the lines into place. That seemed like an ideal way to kink the lines or have them rubbing on something. The tubing is fairly thick, but it will wear a hole in a hurry if an oil line is touching cast iron. It only took about 10 minutes to remove and properly re-form the lines so they fit correctly. Please use a proper flare nut wrench on those soft oil line fittings. A standard open-end wrench or vice grip pliers, will ruin the nuts. The flare nut wrenches are wider and make contact with more sides of the nut.


HYDRAULIC FLUID: Refer to the new section on Hydraulics.


The original spec calls for Champion H-10 plugs. After extensive real-world experience, most owners of these tractors are using Autolite 437 plugs. These plugs run a little hotter and stay cleaner than the original plugs. Yes, you could simply go one heat range higher and stay with Champion plugs. That should accomplish the same thing. If you are doing a full restoration you may want to use the exact original plugs. It's up to you, but I have been using the Autolight 437 plugs and have almost never had to remove and dry them off to get my tractor started, even when flooded.

If you use the choke at all, you will flood one of these tractors. Most of them are incredibly easy to flood. It only takes a little too much choke. With some plugs, your only option at that point is to remove them and dry them off or put in a dry set. The best way I have found to dry and clean plugs is to cook them a little with a propane torch, then blow the soot out with compressed air. Don't melt them down, just cook off the deposits.













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