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Hello. I'm doing a rear axle service on my M38. I'm trying to install the inner oil seal in the axle housing. the problem is that the inner oil seals I received in the rebuild kit are junk. The metal is so thin that no matter how gently I try to tap them in they quickly deform because the metal is so thin. The seal I took out was pretty substantial, not like the thin parts I am working with now. Does anyone have a suggestion on where to get quality oil seals like the originals? Thanks.

Just as a side note, I was really surprised at the amount of force required to get all this apart. I used a three jaw slide hammer puller to pull the axle shaft and it took quite a few really hard pulls to pop them loose. I also had to pound really hard to get the bearing cone off the shaft. I've been using TM9-8012 as my guide and it makes it seem like all this stuff just comes apart by hand. I know this one has not been touched for decades so maybe that is the reason for all the effort.

Go to Napa and have them pull a seal off the shelf. I believe the seals are the same all the way up to a 1970 CJ-5
The bearing cone better be on there, its an interfernce fit and has to be pressed on/off.

Now I'm really confused. Does the bearing cone have to be pressed on? TM9 says "Position the bearing cup over the cone and tap the cup and cone on the axle shaft until the cone seats." It never mentions the use of a press. Any thoughts on this?

I see what you are saying reading that.

(3) Position the bearing cone on the axle shaft with the
small end of the bearing taper facing out. Position the
bearing cup over the cone and tap the cup and cone on
the axle shaft until the cone seats.

Both of my old ones had be pressed off and even the new bearing had to be pressed on. I dont know if back then the bearings were looser and they slipped on? I have to admit that this is only my 2nd axle Ive ever rebuilt but the other one was from a Cherokee and it was Dana 44. They pressed on also. I searched the forums and most are saying interference fit requiring them to be pressed. An interference fit will prevent a spun bearing. Same with the cup in how its snug in the housing.

Most likely yours are installed correctly so they if you are replacing them, they have to go back on the same way. I can't see how they could be installed incorrecly.

I'm no expert by any stretch but I think the reason the bearing has to be pressed on and off is to insure that the inner race of the cone does not spin on the axle itself. Both of mine had to be pressed off and new ones pressed on. Just another one of those tasks that while you're doing it you swear up and down today is the day you are going to buy that hydraulic press.....and you keep saying it all the way to the machine shop....where they charge you a dollar to press the old ones off and the new ones on....and then the light bulb comes on about why you still don't have a press.

Ditto, press on/off the inner bearing. Once the shaft is installed carefully so you don't wreck the outer seal you put in new, You tap in the race last. Make sure you put the shims on next, and then the thick spacer. The thick spacer has a hole smaller than the race! I learned this the hard way Duh! To install the seal, use a socket or seal driver that fits the OD of the seal with a little clearance. Then with extensions as needed you drive it in squarely with a hammer. Everything clean and re-lubed! You'll get the hang of it! It just costs money everytime you mess up. John

The National Seal number for the rear axle shaft seal on a Dana 44 is 42763. Most dealers should be able to cross-reference that if they don't carry National.

You're right, the manual says to tap the cone into place on the axle using the cup, and I imagine that could be done in a pinch, but it is a heck of a lot easier, more effective, and safer on the bearing to press it on. It is definitely a press fit and not a slip fit. My son and I had two axles to completely rebuild (including differentials), so, being a tool junkie, I used that as a justification to finally buy myself a shop press: http://www.harborfreight.com/20-ton-sho ... 32879.html I cannot imagine doing any of that job without it, a bearing separator, and the various blocks of steel, pieces of tubing, 3/4" drive sockets, etc. that were used as accessories with the press. If we were doing just the rear axle shaft bearings, the cost of the press wouldn't have been justified (idiocrates' point), but I've used it for pressing in spring bushings, suspension bushings (different vehicle), flattening the skid plate, and even bending metal and I haven't even owned it for a year yet. [edit 8/17/11: just used it again this morning to press the pitman arm off the steering gear shaft - came off with a real bang. That sucker was on there so tight I couldn't budge it at all with a pitman arm puller or a gear puller.]

I installed my seals with a large socket (again, from the cheap HF 3/4" drive set) just like oilleaker1 did, but even then they wanted to warp and I had to do some final finessing to flatten them.

On my axle the bearing cups were a "tap fit" into the axle housing, using a light hammer and working around the cup. I put the first one in too far (see below) and had to use the other axle shaft to tap it back out. This has to be done very gently so as not to damage the bearing.

The "thick spacer" is not a spacer, it is a bearing retainer. It is there to bear against the bearing cup only, so that the brake backing plate doesn't touch the rest of the bearing. You can bolt up the bearings, shims and retainers without all the brake parts, gaskets and outer grease retainers and protectors when you're checking for axle shaft end play. Note: the two axle shafts touch each other end-to-end in the differential, and the end play spec of 0.005"-0.007" is for the entire axle assembly, not each shaft independently. If you have removed both axle shafts and are reassembling them, you cannot check end play by assembling only one shaft because there is nothing to stop it from going in too far (since the other axle isn't in yet). This isn't mentioned at all in the military manuals. If you kept track of what shims you removed from each side, you can use that as a starting point and add or subtract to get the correct play. You may find that one side had some nice round number, like 0.060" or 0.090", of shims, and the fine tuning is all done on the other side with a couple of 0.030" shims and some thinner ones, which makes perfect sense: roughly center and final adjustment done with second and final shaft/bearing/shims assembly. In my case, the only new parts in the tolerance stack-up were the bearings, and using all the original shims gave the perfect end play. Anybody need an unopened set of new shims?

Jim