AIR FILTER ASSEMBLY

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

These tractors all use an Oil Bath type air filter. This is one of the most neglected parts of any tractor. If you recently purchased your tractor, the air filter assembly is probably FILTHY! It's a good bet that the complete assembly needs to be removed and thoroughly cleaned. Not just the oil cup, but the entire filter housing.

Some people will try and tell you the filter housing is "self-cleaning" and the dirt falls back into the oil cup when you shut the engine off. This is only partially correct. The Ford manual says to clean and replace the oil in the oil cup every 10 hours. It also says to completely clean the entire filter housing at least every 600 hours.

If you use your tractor all day (12 hours), every day that would mean servicing the oil cup almost daily and giving the housing a thorough cleaning every 7 weeks. Most people don't use their tractor that much, but even with minimal use, the air filter housing should be cleaned out at least once a year.

Obviously, you don't have to do it every time you service the oil cup, but the only way to thoroughly clean the air filter assembly, is to undo the clips, remove the oil cup. Above the oil cup is a retainer. Remove that and then there should be a couple of coiled metal mesh filters up inside the filter body. You might need to make a tool (a bent piece of wire from a coat hanger works good) to reach up inside the housing and pull out the wire screen material, rat's nest, and whatever is up there.

Thoroughly clean the inside of the filter housing and either clean or replace the metal filter screen. If yours is really dirty, you may want to remove the entire assembly from the tractor to make the job easier.

To remove the housing, you will need to loosten both band clamps at both ends of the air pipe and remove it. Then remove the two bolts that hold the housing to the battery tray. You may also want to disassemble the intake parts at the top.

If the filter media is not too bad, you may be able to unroll it, soak it in solvent, and finish cleaning it with air pressure. For really nasty ones, it is much easier to replace the filter media. Any similar metal mesh will work but you can order the proper replacement material from just8ns.com. No, I don't own stock or get kickbacks from Just8ns. This is simply the best source of parts I have found.

Once the filter body and screen are clean, reinstall the screen and the retainer.

Re-rolling the filter screen can be a trial. If you are having trouble getting the right donut shape, try rolling the material around something that is the correct size. I have found that a tube of caulk works great.

Check the gasket on the oil cup. Replace it if there is any indication that it will not seal properly.

If you removed the air filter housing from the tractor, reinstall it, make sure the air tube is open and clean. Then fill the oil cup to the marked level with new motor oil. Use the same grade of motor oil that you are using in the engine.

You may run into a problem with pin-holes in the oil cup. If the oil leaks out of your oil cup, you may be able to weld, braze or seal those rust holes with something like JB Weld. If not, a new oil cup is usually not too expensive.

The 9N and 2N also have some sort of pre-filter on top of the air filter assembly. Some have an aftermarket extention through the hood and the pre-filter is in the cap on top. Those can usually be cleaned. On the 8N, don't forget to clean the air intake screen behind the louvered opening in the hood. This can get clogged with leaves, dirt, or other trash.

Paper Filters

You may be tempted to try and convert your engine to use a modern pleated paper element instead of the oil bath air cleaner. Be very careful. Nearly all of the paper element type filters that will fit in the available space, will be more restrictive than the original air cleaner. They will trap less dirt and what they do trap makes them even more restrictive.

The original oil bath air cleaner will last indefinitely and usually require nothing more expensive than a little motor oil to maintain it's efficiency.

In my opinion, the only reason manufacturers switched to paper elements was that the oil bath cleaners were messy to maintain and somebody could make more money selling throw-away paper elements. They might even sell more new tractors if your engine sucks up a little more dirt and wears out faster.

For your tractor engine, the oil bath air cleaner will trap more dirt and provide more horsepower than any other filter you are likely to be able to mount on it.

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