NAA Rear Axle Seals

[OrtisEvans]

My Ford NAA needs rear axle seals, a job I've never done. My questions are:
1. I am reasonably comfortable with tools. Can I replace the seals without getting into serious trouble?
2. Do I need any special tools for removal/replacement? I have the NAA repair manual, and it recommends certain tools.
3. Do I need to buy an assortment of shims? Can I just reuse any shims that are there and be ok?

I have searched the net and found a lot of videos on 8n rear axle seal replacement, but I think that the NAA rear end is quite different.

I also searched Tractorbynet and found no helpful discussion.

Best Regards to Everybody
Ortis

 

[RickB]

NAA rear axle seals and associated parts are identical to those found in an 8N but not a 9N OR 2N. Reusing the shims is fine if they are intact. often they are not. 8N / NAA seals are about the easiest Ford rear axle seals to replace as the hub and axle shaft are separate unlike other models.

 

[mapper]

The hub nuts need to be torqued to about 600 ft/lbs if I recall correctly. If they are not tight enough oil will leak into your brakes and the only way to fix that is new brake shoes, I know this from experience, had one leaking when I purchased my 8N. I replaced the seal and tried to clean the shoes with solvent, the brake did work a little bit, but not much.
The hub nuts a pretty thin compared to their diameter, I found that a 3/4" drive socket (2") on a breaker bar with a cheater worked ok to get the nut torqued down, just use your weight and calculate how far out you need to go to get the 600 ft/lb of torque. Remember to check a tighten if needed after a few hours of use.

 

[OrtisEvans]

Thanks Mapper and RickB - you are pretty encouraging. I bought the seals before I knew that there is also a cork seal, a gasket, and shims. Back to the supermarket.

 

[Soundguy]

Thanks Mapper and RickB - you are pretty encouraging. I bought the seals before I knew that there is also a cork seal, a gasket, and shims. Back to the supermarket.

Ditto what rick said. lat 8n with inner/outter seals are identical to naa seal jobs.

 

[Soundguy]

The hub nuts need to be torqued to about 600 ft/lbs if I recall correctly. If they are not tight enough oil will leak into your brakes .

Well.. if the nut isn't tight, the hub will be loose, and then the hub, and perhaps the axle will wear and then you will get leaking seals as a product of the compound problem.

 

[motownbrowne]

Ditto what rick said. lat 8n with inner/outter seals are identical to naa seal jobs.

If it's identical to a late 8N as Soundguy says (and his word is gold when it comes to these Fords) then you'll have no problem doing it with basic tools and even minimal mechanical aptitude. I did mine on my 52 8N last year and it was very simple. Only thing I would've done differently is taken pictures of the brake assembly to help when it came time to put it back together.

The only other tip I can think of is to buy an impact driver. Not the air or electric kind, the $8 one that you hit with a hammer. The flat head screws that hold the brake drum on were a real bear on my 8N. I used heat, penetrating oil, and an impact driver and they came right out (after I twisted the bit on my biggest screwdriver).

 

[OrtisEvans]

Thanks everybody -
I finally did the job this weekend and I have a couple comments.
1. I got new axle nuts, but found that the axle I work on is not the same size as the other - it's a smaller castle nut held in place by a cotter pin. Does that make any sense?

2. There were no gaskets that I could see - just three metal shims.

3. Reassembly was a challenge. When disassembling, I failed to notice that the bolt holes bearing retainer are not all the same. Some are threaded and some are not, as I should have realized during disassembly. So, I had the mess of having hands sticky with gasket cement while juggling parts to get bolts in, and then taking apart to reorient the bearing cap. I'll know better when I do the left one. The manual was written like other manuals I've seen - if you already know how to do the job and just need a few reminders, it is fine, but it does not warn of pitfalls or even give a really clear diagram.

4. getting the hub off and removing and replacing the seals was relatively easy, and the splines are in great shape.

Still, an ok project and I will be glad I did it when I start mowing this spring.

Ortis

 

[Soundguy]

did someone rethread your axle to a different thread pitch/diameter? rare but i have seen it.

 

[OrtisEvans]

Hard to say. The diameter is definitely smaller, and it has a through-hole to take a cotter pin. That is fairly major surgery, if someone cut down the original shaft and not something a shade-tree mechanic could be expected to be able to do.

If SoundGuy does not instantly know what is going on there, no one does. Thanks