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Ford Tractor Hydraulic System

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

As with other things, I like to tackle any sort of lift problem by first checking the possible causes that are No-Cost or Low-Cost items. So, how's the weather? That is a good conversation starter, and there is a good reason to talk about the weather, It affects everything.

1 - Has it rained or been humid recently?
2 - Did it freeze last night?
3 - Is it below freezing now?
4 - Do you leave your tractor parked outside?
5 - Is you rubber boot in the shifter in good shape?
6 - How long has it been since you changed the hydraulic fluid?


Almost left this one out. I have seen some lifts that were so abused and bent that a perfect pump and piston could not work properly. Straightening and repairing the lift arms and other hardware is mostly just time and energy. If someone has substituted bolts where there should be pins, replace them with the correct hardware. If you don't have tools to straighten what is bent, new parts are available. A shop press is ideal, but creative use of a floor jack or bottle jack and heavy chain can straighten lots of parts. Any improvement will help. BE CAREFUL! Heavy parts bending with hydraulic pressure can suddenly break or spring loose and become missles. Don't put your body under or in line with any force you are employing. I got in the habit of wearing safety glasses 100% of the time in my shop. Wear them enough and you forget you have them on.


Water in the hydraulic fluid can be very bad. First, it causes rust and corrosion. Even small amounts of water in the pump can cause valves to stick, springs to break, or linkage to bend. Water is heavier than oil, so it collects at the bottom of your sump (where the pump is located).

Water is bad, ice can be worse. Large amounts of water in the sump can freeze and crack the cast iron housings! Small amounts can lock parts and prevent them from moving.

Warm things up by bringing the tractor into a garage or with a portable heat source. Once things are warm enough not to be frozen, get a pan or pail and crack open the three drains at the bottom of the hydraulic sump. Do them one at a time and only crack them open. What I mean is only unscrew them enough to get a gush of water. When the water stops, turn the plug closed again. Water will go right past the last couple of threads, the thicker fluid won't come out unless you go too far. Do that and you may get several gallons of oil in the face or running down your arm as you frantically try to thread the plug back in.

Daily use of your tractor will constantly evaporate any moisture from condensation. But if your tractor has been sitting for a while, or you generally leave it outside in the weather, it is a good idea to drain off any water that may have accumulated in the sump (not a bad idea to also do this to the engine oil sump while you are under there). In humid months, you can collect quite a bit of water in the sump just from condensation.

If you get a lot of water (more than a point or so), check your boot on the shifter for cracks. A $5 shifter boot is much cheaper than five gallons of hydraulic oil or a frozen and broken hydraulic pump!

Simply draining off any water can fix some problems. If that didn't do it, read on.


The N tractors have a common sump for the rear end, hydraulic pump and transmission. Therefore, the fluid used in these Ford tractors is a combination gear lubricant/hydraulic fluid. You should never use straight hydraulic fluid or straight gear lube in this sump. The original Ford recommended fluid for the 9N tractor was Straight Mineral Oil, SAE 90. For winter use in really cold climates SAE 80 could be used. This fluid would correspond to the modern API Gear Oil designation GL1.

Oil technology improved over time and the fluid specification was upgraded around 1950 to “Mild EP GEAR OIL conforming to Ford specs M4864A (SAE 80) (below freezing) or M4864B (SAE 90) (above freezing)”. The modern equivalent is API gear oil designation GL3.

If you walk into a New Holland dealership today and ask, the fluid they will recommend for all "N" series tractors is a combined hydraulic/transmission fluid which conforms to their specification M2C134D. This is a synthetic fluid that is much thinner than the earlier products, so it is a much better choice for year-round use. My tractors work hard, but they don't get nearly enough hours to justify changing the fluid twice a year. This is the best fluid for me to use in my tractors.

If we wander into the local Tractor Supply Company ®, and start reading labels, we will find three products that might work:

1 - Traveller ® Ford Tractor All Mineral SAE 90 Ford Tractor Transmission Fluid. This is as close as you are going to find to the originally recommended fluid for the 9N and 2N tractors. This is an API Gear Oil designation GL1, and is probably going to be the least expensive fluid available unless you catch one of the others on sale. This is also the earliest specified fluid, so simple logic says the later specified fluids are better.

2 - Traveller ® RENEW for Older Tractors, Universal Tractor Trans/Hydraulic Fluid. Read the label carefully. Universal Tractor fluids are often formulated to work for most tractors, but if it does not say that it "MEETS" the Ford specification it very likely does not meet the specification. I believe this is going to be a GL3 or GL5 product that will be better than the GL1, but if it does not say that it meets Ford specification M4864A or B I am not going to use it in my tractors.

3 - Traveller ® Premium Universal Tractor Trans/Hydraulic Fluid. SAME AS ABOVE, Read the label carefully. This one may actually says it is recommended for use in place of the Ford M2C134D fluid. So who recommends it? Same as above, if it doesn't actually "meet" the Ford spec, I'm going to keep looking.

After looking around, my choice was to go back to the New Holland dealer and buy the expensive Ambra Multi-G 134 (NH-410B) synthetic fluid that meets Ford M2C134D specifications. It was about $5 more per gallon than the lowest price I could get at TSC or NAPA for products that were inferior and might have to be changed twice a year. For a year-round fluid, I am saving money and maintenance.

Some people claim the synthetic leaks more. For a trailer queen that sees little real use, you could rebuild all of the seals and stop the drips. My tractors are working tractors and I don't mind if they mark their territory with an occasional drip. If a leak gets worse, I fix the leak.


To completely drain the hydraulic system, there are three drain plugs. Two large plugs under the transmission and pump and one smaller pipe plug under the differential housing. There is only one filler cap located on top near the gear shift lever.

When you are ready to drain the sump, you will need a container that holds about 5-gallons.

When changing the fluid, try to flush as much of the sludge as possible out with the old fluid. Just like changing the oil in the crankcase, it is better if you drain it when the fluid is at least warm. It runs out quicker and more stuff is suspended in it. You can use one drain pan to catch the fluid by starting with the pipe plug under the rear end and moving forward to the large plug at the hydraulic pump and then the last one at the transmission. Some people recommend flushing the system with kerosene. They drain the sump, pour in a couple of gallons of kerosene, start the engine, engage the PTO and run the lift up and down a couple of times. Then they remove all three plugs and let it drain overnight. This procedure of-course requires three drain pans.


Once the sump has been completly drained, replace the three drain plugs and then remove the bottom bolt from the inspection plate that has the hydraulic dip-stick. (Remove the same bolt from teh inspection cover on teh other side if you are not on level ground.) Start filling the sump and stop when the fluid begins to leak out of the bolt hole. That is all you need, any more will just leak past the axle seals and get on your brakes. It usually takes 4-1/2 to 4-3/4 gallons not 5 as stated in the owners manual. Pull the dipstick and, if necessary, make a new mark that corresponds to the correct level.


Attach a heavy implement (anything weighing at least 150 pounds should be enough). Remove the right inspection plate that has the hydraulic dip-stick. Start the tractor, press the clutch, make sure the PTO is engaged. The PTO shaft should spin when you release the clutch. Raise the implement while watching the fluid through the inspection hole. Look for leaks coming from above. Small leaks have a tendency to get bigger, but you should be able to judge if your leaks are bad enough to have to remove the top cover and fix them. Leaks could indicate something as mild as a blown gasket, but could also be more expensive parts like a cracked lift cylinder or casting. A mirror can be used to try and pinpoint where the leak is. A new top cover gasket set is pretty cheap.

Removing and replacing the top cover is a relatively simple proceedure that is covered pretty well in the I&T FO-4 manual. The only thing I can add is that it helps to have two people, one to do the heavy lifting, another to stick their hands in the goo and guide the linkage into place as the cover is lowered. It is hard, but not impossible, to do both with only one pair of hands. DO NOT start to bolt the top cover down until you have made sure the linkage is correctly placed and not binding. Never force anything! If it won't go easy, stop and figure out why. The two-sided linkage on the 9N/2N is a much bigger pain in the rump to get hooked up. Don't attempt to do it from just the right side cover. You need to be able to grab both pieces and stretch them into place. You will want to do this when the wife isn't around. There is simply no way to explain why you were hugging your tractor with one arm in each inspection hole. GRIN

If you do need to remove the top cover, that is a good time to check, repair, and readjust the linkage. I can add very little to that proceedure. Check my LINKS page for a link to Zane Sherman's website. He sells a jig and booklet of instructions for repairing and adjusting the 8N lift. It is worth every nickle of the asking price for his expert advice and instruction.

If you are really short on funds, it is possible to repair and adjust your lift using just the instructions in the I&T FO-4 manual. The 9N-2N lift is much simpler with only one external adjustment.


While you are looking for leaks, you should see some indication that fluid is being sucked into the pump from the sump. No leaks, and no indication of suction, could be stuck valves or something major broken in the pump. FIRST push the clutch in and make SURE the PTO is engaged. Drain off some fluid to expose the top of the pump. This should allow you to see if the excentric cams and pistons are moving properly. There are two piston assemblies that should move at the same time, and in opposite directions. A "chuckling" sound under load usually means the excentric cams are worn but the pump can make a lot of noise and still work ok. Shuddering on the upswing usually indicates one or more valves in the pump are sticking or not sealing properly. Rebuild kits can be purchased in various stages depending on what needs to be rebuilt. Once again, I have little to add to the diagnostic and repair proceedures in the I&T FO-4 manual.

Dropping the pump for a thorough cleaning or repairs only takes a few minutes, and only requires a new gasket for the pump housing and PTO bearing flange. Drain the sump. Remove the PTO shaft. There are four bolts around the PTO bearing flange. Remove those and the shaft pulls straight out the back. Check the bearing. If that is loose or the seal was leaking, plan on replacing the bearing and seal while you have it out. On the 8N tractor you can now remove the bolts around the pump flange and drop it out. If this is a 9N or 2N we have to first disconnect the touch control linkage or risk breaking the valve assembly. Linkage Tips are in the next paragraph.


The most common problems with the 8N linkage are wear and bent linkage. Look at the 8N link that goes down to the valve. It should be straight. If that link is bent, the top cover has to come off and there are usually other parts that need attention. Most are covered well enough in the manual. The 9N-2N linkage is different and not usually bent, however, before removing the top cover or dropping the pump out of the 9N-2N tractors, the linkage must be disconnected. Accomplishing that when working alone is much easier said than done. Reconnecting the links, even with a helper is nearly as difficult. The linkage inside the housing is spring-loaded. How does one person pull out on the touch control linkage from both side covers, at the same time? I've done this with the seat removed, laying on the tractor, with an arm in each hole. There has got to be a better way. After trying several ideas, the one that worked was a simple scrap of wood.

The scrap was cut to 0.375" x 0.75" x 3.75" and wedged between the two linkage arms with one hand, working through the right inspection hole, with the touch control lever in the full DOWN position. With the wooden wedge in place, we can now reach under the tractor and tickle the valve link loose while still looking thru the side inspection hole. Piece of cake, and there is no need to remove the other inspection cover.

Reinstalling the cleaned, replacement, or rebuilt pump can be tricky. The pump has to be wiggled up into place and then the front edge of the pump overlaps the front lip. It helps to have something like a block of wood under an elbow to help hold the pump if it does not go in perfectly on the first try.

Once the pump is back in place, reach thru the drain hole and put the valve links at the pockets on each leg of the linkage, then carefully pull the wooden wedge out, hopefully capturing both sides of the valve assembly in the pockets.

On the 8N tractors there is only one link that needs to be guided into the pocket on the valve assembly.


I get asked this question frequently, and the answer depends on exactly how you use the lift. It also depends on how much weight you have on the front end. With about 800 pounds at the end of the lift arms, the front tires get very light, especially if you need to go up-hill. At that point you will be steering mostly with the brakes and risking flipping over backwards. Out on the end of a boom pole, the lift has a lot less leverage. I've seen a 1200 pound round bale on a 3-point bale spike on the back of an 8N, but he also had a loader bucket on the front to balance it. It can be done, but I think that qualifies as abuse.


This one is a separate page Live Hydraulics. Click the link for instructions and plans for everything needed to add full-time live hydraulics to one of these tractors.

RETURN - to main TUNE-UP page or go to the next subject BRAKES


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