Rear axle seals and bearings

[okie]

I have a 93 f350 with leaking rear axle. The job looks easier than some other bearing replacements but figuring out replacement parts needed is near impossible. I've id the axle as a sterling 10.25 full float 7400GAW and all parts diagrams and videos show 2 seals (inner and outer). Nobody know what parts. I've talked to all 3 parts stores plus ford dealer parts (worst). Searched All internet parts vendors. Read every related forum here and everywhere else. Best I can find is opinion for the inner seal (scotseal plus xl) among others, maybe. Part stores know nothing about outer and nobody else talks about it. If anyone knows what bearings and seals are a good fit please let me know. Also this diff has no fill hole, sure of it. My best guess is the ABS sensor.
Thanks for any and all info.

 

[Cubey]

I have a 93 f350 with leaking rear axle. The job looks easier than some other bearing replacements but figuring out replacement parts needed is near impossible. I've id the axle as a sterling 10.25 full float 7400GAW and all parts diagrams and videos show 2 seals (inner and outer). Nobody know what parts. I've talked to all 3 parts stores plus ford dealer parts (worst). Searched All internet parts vendors. Read every related forum here and everywhere else. Best I can find is opinion for the inner seal (scotseal plus xl) among others, maybe. Part stores know nothing about outer and nobody else talks about it. If anyone knows what bearings and seals are a good fit please let me know. Also this diff has no fill hole, sure of it. My best guess is the ABS sensor.
Thanks for any and all info.

I replaced the rear wheel seals on my RV's Dana 70 (dually full floating) a year ago with $9/each Driveworks ones from Advance Auto. They were basically just rebranded WJB seals, very cheap from RockAuto (under $2/each) vs what paid from Advance but that's besides the point. They have been holding up fine for a year under a heavy load full time.

This is the "outer seal" on a full floater, it's called "axle flange gasket".

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How it looks (with RTV):

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Do make sure you use RTV on that flange gasket because the RH side on mine did start leaking after about a year without RTV, and I had to go back and do that. That's why the rim is so disgusting. The other side isn't leaking yet but I suspect it will eventually. I applied the RTV to the spindle first then stuck on the gasket, then applied RTV to the side you see in the photo.

The probably original 1985 bearings were still in excellent condition, so I just cleaned and regreased them. I made sure which bearing set went to which side so they got put back on the same sides they came from. I did the same for the front bearings since the inner seals were getting replaced too while I was replacing the rotors.

If wheel bearings don't look or feel bad, I personally see no point in replacing them.

 

[ROCK HARVEY]

I was wondering what outer seal you were seeing in the diagrams, until Cubey pointed out the outer gaskets. If your inner seal is the one leaking, I bet you have a bad bearing that allowed enough play for oil to get past the seal. I watched a really good YouTube video recently of a guy replacing his axle seal and bearings (I spend 90% of my spare time watching IDI videos on YouTube lol), and his video description lists the following part #s for his 1990 F-250:

Outer bearing: National 3994
Inner bearing: National 3920
Axle seal: National 370047A

 

[Cubey]

I should also ask, which side of the tire is the oil showing up on?

This is on a dually, so if you have SRW, it might not show up the same way, but this is how it looked when my inner seal was leaking. It was running down the inside of the inner tire. The inner seal (FoMoCo one from 1985!) was leaking oil into the drum and it ran out of the drum down to the tire as you see:

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When my axle flange gasket was leaking, it was showing up on the outer side of the wheel, being flung around on the rim.

 

[okie]

A lot of the seal and bearings I've found that say their for the 10.25 have different ID and OD. Also doesn't a seal go outside each bearing and an oring where Cubey put RTV?

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[ROCK HARVEY]

I think those are bearing races for the tapered bearings, not seals that you’re seeing outside of each bearing. Bearings and seals should be the same for all 10.25 axles from 1985-1997, so if a trusted website says it fits then You should be good to go.

 

[ROCK HARVEY]

Oh and don’t forget you need that special tool (spindle nut socket?) for those funky ratcheting spindle nuts.

 

[Cubey]

A lot of the seal and bearings I've found that say their for the 10.25 have different ID and OD. Also doesn't a seal go outside each bearing and an oring where Cubey put RTV?

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Ah, I wasn't sure how Sterlings are since I've only ever messed with Dana 60 and 70 full floaters and they have flange gaskets. I can't recall how my F250's semi floating is.

 

[Cubey]

Oh and don’t forget you need that special tool (spindle nut socket?) for those funky ratcheting spindle nuts.

Ah yep. I bought one for my F250's Sterling Semifloater since I had to get at the inner seal. I couldn't find one at O'Reilly, AutoZone or Advance. Only Napa had it, for some reason.

I switched my RV's nyloc nuts to the ratcheting kind, even though it's RH thread on both sides. If a tiny bit of thin steel and some nylon can keep the original style nut from backing off on the LH side, than I'm sure the racheting nuts can stay put. It's been on there for several thousand miles now including rough gravel roads, and it's staying on fine.

 

[okie]

49 and 46 would be the races. 44 and 51 would be the seals

 

[Cubey]

49 and 46 would be the races. 44 and 51 would be the seals

51 looks to be the spindle nut

53 looks to be a flange o-ring seal

 

[IDIBRONCO]

Okie, your diagram is a very poor one (it doesn't matter where it came from). 53 is probably supposed to be the gasket the Cubey showed while 51, despite appearances, can only be one of the ratcheting spindle nuts that ROCK HARVEY mentioned. If 51 is a seal, then what holds the preload on bearing 50? With nothing holding bearing 50 in place, the there's nothing to hold the hub onto the axle housing. The proper inner seal is the National 370047A that ROCK HARVEY also mentioned. The Scotseal equivalent is a very good seal too. Sometimes the Scotseal works when the National seals won't. I couldn't get a National seal to hold for very long in my Blue Truck on the passenger's side so I finally went with a Scotseal and it's been fine. A National seal did work fine on the driver's side. I don't know what's different between the two side, but something is, at least on my truck.

 

[TNBrett]

Cubey touched on it, but it’s worth pointing out, the spindle nut is left hand threaded on the driver’s side. I think I’m correct on which side, but the bigger point is one of them is.

The axle flange seal on the sterling is a large o-ring. I’m sure there’s an industrial cross over, but when I went through mine, I could only find it as a Dorman part. I’m thinking it was like $5 for a pair of them on RockAuto.

I’ll give another vote for the Scotseal XL plus as well. Much easier to install correctly than the older style seals.

 

[Cubey]

Cubey touched on it, but it’s worth pointing out, the spindle nut is left hand threaded on the driver’s side. I think I’m correct on which side, but the bigger point is one of them is.

The axle flange seal on the sterling is a large o-ring. I’m sure there’s an industrial cross over, but when I went through mine, I could only find it as a Dorman part. I’m thinking it was like $5 for a pair of them on RockAuto.

Yes on the driver side spindle nut.

Dug up the O-rings

Dorman Products - 926-163

Rear Axle O-Ring Kit

www.dormanproducts.com

 

[Cubey]

Oh and I guess my 87 F250 HD is actually a full floater. Makes sense, given the HD designation. I do know it's a Sterling 10.25 and the inner seal was expensive (~$30) from O'Reilly and their current $33 inner seal for Sterling 10.25" says full floating. What throws me off is the drum comes off without the hub, unlike Dana 60/70. Pic is from February 2017, so it's been a while since I had it apart. I don't see the O-ring seal but it might just be hiding behind the can of brake cleaner.

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