Farmall m crankshaft

I am restoring a 1941 farmall m and was needing to know if it was possible to drop the crank shaft and change the rear main seal without having to split the tractor. If i do have to split the tractor what is the best way of doing it my floor jack dosn't reach the bottom if the frame rail.

I have changed main bearings with some tool that looks like a roofing nail. Put it in the oil hole and tun the crankshaft, It will roll out. This is an expedient repair and not really part of a restoration. You may need to loosen the main caps What bearing you use is a guess

It has been close to 50 years since we had the MD apart and it would not necessarily be pertinent to your gasser. I believe you have to split it to get the rear seal out and I believe it bolts to the back of the block so it can be done without pulling the crank. Use the jack under the back half and make beg borrow or steal some good splitting stands for the front.

Not sure the wick seal , I never done one in engine . Photo of installation that recommended . I dont see how you can get .015 interferences fit with out crankshaft removal and inspection .

I've never split one, but.... I'm pretty sure I wouldn't even think about tackeling that if all I had was a floor jack.

I've put rod bearings in before. Left engine in the tractor for that. Was gonna roll new mains in also, even had them out (one at a time). But ended up putting the old mains back in. They didn't look bad, and the new ones I ordered were of the wrong size (crank had been turned down on previous overhaul). Only done this because I put new rings in, and I was already there. I just didn't even bother with replacing main seals. I knew the existing ones weren't leaking, and just left that part as it was.
Definately not something I'd fix, unless I knew the seals were bad (leaking). I don't think I'd bother about it just because of the simple reason I was changing out some of the other seals.
Doing a restore, and I knew they were leaking, ... maybe. But I definately wouldn't be doing it, just to be doing it, so I could say I replaced all the seals. If ever a place to apply, don't fix what isn't broke, this would be one of those places to apply that.

Not sure how that model is designed, but very seldom can a rear main be successfully changed inframe.

Also a leaking rear main is usually a symptom of more serious problems, as in loose bearings, and excess blow by. Rarely will even a new seal be a permanent fix if the rest of the engine is not healthy.

As for splitting the tractor, you need more than a floor jack. A solid concrete floor is a near necessity. Good cribbing under transmission is the only safe way, jack stands are not stable.

As for the front, you have to be very careful, once separated from the rear, the center pivot will let the engine fall side to side.

Since you are doing a restore, I would go ahead and disassemble everything from the engine, then lift the engine with a hoist or cherry picker. Much safer that way, and controllable going back together.

most of the older guys with rope seal installation experience are getting few and fewer, just saying. neoprene seals not as bad to do. yes a split is for sure. remove flywheel and go at it. leave crank alone.

I must be one of those ..older guys.. that have replaced rope seals with the engine in the unit, cars and trucks mostly. They are tricky, it is kind of like the birthing process of fitting something big through a small hole. If you are doing a ..restoration.. to me that means you would be splitting the tractor anyway to restore the clutch to original specs. Most likely you are doing a ..rehabilitation.. where if something works okay it is not touched. Anyway to split it safely you need a splitting stand or at least a facsimile of one. Do a web search for one. On an M you can get by with a couple of 6 channel iron that are long enough to go from the side frame rail rails to the floor. Bolt them on each side as far back as possible. Then put your ..2 TON plus GOOD floor jack that does NOT LEAK down.. under the clutch housing so you can roll the back half back. This is actually the marginally safe method. The best way is to have the front part of the stand that bolts below the engine equipped with heavy casters. Then to also have the ability to adjust the height of each side with a jack or threaded adjustment. Then a bottle type jack is used under the clutch housing and in this configuration the engine rolls forward. If you are used to automotive stuff BE CAREFUL comparatively the parts of this machine are heavy!
Not sure if you are familiar with it but I am adding a link to the manufacturers online parts diagrams. To see the rough configuration of the rear crank seal go to Engine and subsection 014. Best of luck!
CNHI Farmall M online parts diagram

A M or H do not have to be split for clutch. Will have to to get flywheel off. The dowel studs can be fun to get out. One of them starter has to come off to get buckleup bolt out.

Yes but need to drop oil pan. After engine is split from center housing the clutch and flywheel is removed. Two seal holders bolt to back of block, one below and other above. Also the flat plate bolted to bottom of lower seal holder needs removed. Better to remove plate on rear of engine when doing that. Make sure seal flanges are flat across and behind. Put all the seal halves you can in each half. Not supposed to trim any off that sticks above the half, but sometimes they will leave to much. Gasket goes behind the halves and between each side where they meet, also for plate on bottom and two plugs at ends of plate. For a tighter fit on crank if wanted I have left out the thin gaskets between flanges and used a real thin coat of the best type sealer I though was right for the job. When installing tighten seal flanges enough to keep them flat to block then tighten the two bolts that pull flanges together, then finish the others.

Can you even get a rope seal anymore? Last one I saw was for a 318in a 65 Plymouth and tractors of the 40'sor 50's. It has been a long time since I have put them in too.

Shaun, I realize that about the clutch replacement. It is my opinion that if he had to ask he will be much happier performing the task with the tractor split. Quite a bit of tom foolery going on to replace that seal without splitting the tractor.

Yes search 57613da felt seals. They come in complete gasket sets also. Some places sell a kit with them and gaskets for parts removed to change except oil pan gasket.