Ford 8N, NAA Crankshaft Rear Oil Seal

David Fast Can the crankshaft rear oil seal in a 1954 Ford NAA tractor be replaced without pulling the engine? (May seem like a stupid question but I don’t know.)
Leon The neoprene type you can, the part # is C0NN6701A. If you have the rope seal you have to pull the engine.


Bob G I don’t know about your engine, but the 8N book says you can replace the rope seals by just pulling the pan, but don’t know how easy it might be.
Leon Hey Bob,

That was an ingenious design that Ford put on the 9/8/2N designs. The upper rear main seal is actually in a retainer that can be removed while the crankshaft is in. For some reason they decided not to do the same on the overhead valve models. But they did make a piece of steel wrapped in neoprene to take the place of the rope seal so it could be replaced with the crankshaft in.


David Fast Right. Same thing in the shop manual I have, but I don’t know if it is the engine leaking or the trans. The oil in the trans seems to be quite low and it is kinda brownish and almost foamy. It’s kind scary looking. Also, I don’t know which of the plugs on the side of the trans is the one used to check the oil level. There is one on the left side and two on the right side, on high and one low. If I crack the low one oil will come out.
David Fast I don’t think anything is easy but it appears that you are right. My book says to loosen the caps on the fwd and center main caps to let the crank drop down a bit and remove the rear cap, run a screw into the old rope seal (if that is what is there) and pull it out. Then replace with new neoprene seal. Could work I guess.
David Fast Thanks Leon and Bob G. I am going to see if the local Ford (New Holland) guy has the parts I need. If not do either of you guys know a good online source?? df
Bob G check for a dipstick on the right side under the seat area. don’t remove any bolts that are on either side. except the ones holding the round inspection plate if the naa has it. on the 8n the dipstick is on the right side inspection plate.

you can get the neoprene rear engine seals from for 8.50 plus shipping

maybe someone with a NAA can tell you about checking for oil level. should be in your manual tho.

keep us posted

Don David, i had the oil pan off of my 8N a while back to change out a rod bearing……….the rope gaskets on it were right at each end of the oil pan and look fairly easy to change……..mine were good so i didnt change them………but i had half of the tractor apart just to get to the pan…..hope your tractor isnt as hard to get to the pan………….Good luck
Leon To check your transmission oil you want to pull the square-headed pipe plug from the housing, oil should be just below the threads. Now as for it’s location…I believe it is on the right hand side, go straight down from the shift cover and it should be just above your running board. Transmission takes gear oil and you fill it through the big plug on top of the shifter. The hydraulics is checked by the dipstick with 3 point in down position, it takes Ford M134 oil and is filled by the big plug under the seat on the left hand side of the top cover. Rear end takes gear oil and is checked by the square-headed pipe plug just behind the left hand axle housing. That is filled through the big plug on the rear end housing just to the right of the rocker where your top link attaches.

I think in your last post you said that the leaking oil was black, I’m going to guess that your leak is in the rear main seal. And, yes, the screw trick works to get the old seal out.


Jim Loveridge David, I just read all the posts about your oil leak problem. I just wanted to add that the weep hole that Bob talked about is way in the back of the clutch housing, just ahead of the trasmission. Mine didn’t have the cotter pin in it which caused it to plug up and water from condesation etc. couldn’t leak out and caused my clutch to stick and my starter drive to get all rusted and gummed up. Because you say the oil that is leaking out is black, I would sure check that weep hole.
David Fast Jim, I know where that is and there is a cotter pin in it. What am I suppose to be looking for? Should it be dry in that area or what? df
Jim Loveridge If you aren’t getting any oil dripping out of that hole then you must have a rear main seal leak like you think. Hope you can get it changed out without too much of a headache.
Don If your tractor is like my 8N you will have the hood,grille,front end off of tractor…….when you take the front end off there are a couple of bolts for the oil pan behind it
David Fast Could someone who has changed the rear crank seal on an NAA please explain the exercise to me. I have read in the manual that it can be done without pulling the engine but it just isn’t making sense to me. The Ford Shop Manual says it can be done but I can’t seem to be able to lower the crank by loosening the front and center bearing caps. How loose do they have to be? df
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