Oil seals for ball bearing rear axle

[Reno Speedster]

I am getting ready to start assembling the rear axle for my 26 speedster. I am using the inner ball bearing setup (replacing the Hyatt bearings) and the ball bearing safety hub that puts the weight of the car directly on the axle housing. I am wondering what seals I should be using (and where to put them) to keep differential oil out of the brakes. Do I need to run seals at all?

[Dan McEachern]

Post some pictures of your safety hubs and then some suggestions can be made.

[Mark Gregush]

If they are the safety hubs from the suppliers, Fun Project (?), none. They should be shielded/sealed bearings and the rubber o rings on the outside will seal there too. Unless you have fully machined axles, you are going to have to pull the gears off to install the inner ones, the instructions should cover that. Hope you have a good press to pull and install those gears. Do you have the parts on hand to look at them?

[Reno Speedster]

The hubs are from Texas Ts and they do have the o ring on the outside. I do have a good press and all the parts (axles, gears, bearings) are new, so I would be changing the gears anyway.

[Mark Gregush]

Ok, sounds like you are good to go! RE the inner bearing, because other that might be thinking about do the same, gives them a bit more information. Even the solid type roller bearings will not fit over many original axles to use as inners.

[Allan]

I have rarely found the inner journal on an axle which was worn enough to warrant changing it out. If you have new axles, a good original Hyatt bearing and sleeve should do the trick.
Do not resort to heavy loads when pressing the axle gears onto your new axles. Support the taper in an old hub so you are not pressing on the thread at the end. If the gear will not slide on with moderate load, the axle itself needs a tubular sleeve to keep it from bowing under heavier load. It is good practice to carefully measure the new axles and the gear to check tolerances before loading up.

Allan from down under.

[Reno Speedster]

Thanks for the tip. This is going into my long running speedster project and I am using ball bearings in keeping with the speed equipment available in the 20s. It’s got a hotter cam, a high compression head, dual exhaust, Bosch font plate distributor, a Muncie three speed, and a bunch of other stuff. I have a good (no cracks) Rajo B head waiting to get rebuilt. I am building a mahogany skiff body for the car. Not the lightest possible, but huge style points, if I can ever get it done… I included a couple of pictures of the very slow work in progress.

[AndyClary]

It may be a belt and suspenders deal but I install a set of the neoprene inner seals with the safety hubs. Because, why not.

Andy

[Reno Speedster]

I dug out my axles and tried to slip the inside bearing over the end of the new shaft. The axle is turned/ground over it’s full length but the inner bearing appears to be a press fit on the shaft. It’s been a while since I bought these parts, so I will have to get back into the installation instructions to make sure I know what I am doing.

Andy, the seals are cheap and I am already there, so it might be worth putting one on.

[Mark Gregush]

It may be a belt and suspenders deal but I install a set of the neoprene inner seals with the safety hubs. Because, why not.

Andy

The outer bearing assembly does not reach all the way to where the seal would be installed, so the seal would not be pinched between the bearing and axle tube, allowing it to float between the two. What could happen is the bearing could spin on with the axle, cutting a groove in the housing.

[AndyClary]

The inner seal is the only oil seal, the outer seal is a grease seal. When I install the inner seal I clean and dry inside of the housing as best I can. I install the seal with a bead of silicone on the inside to seal it to the tube. I have had no problem with this method and safety hubs. Past results are not reflective of future performance.

Andy

[olebmw]

Allen, or anyone else. Would it be ok to use a little heat on the back side of the gear after it's set up in the press and ready to push?

[Mark Gregush]

Heating just the back side of the gear would not be the way to do it. The whole gear needs to be heated. When I want to heat a gear or bearing that is a press fit, I do mine in oil on a hot plate. The whole gear is heated and expands more evenly, enough often just to drop into place. Then, when cool, shrinks for a tight fit. There are other ways to do it, that is how I do mine. Oil or oven, even heat and lessens the chance of taking the temper/hardness out if you get too hot. Also, if you can, chilling the shaft it fits on helps too.

[Reno Speedster]

So I measured the new drive shafts and bearing tonight. The old of the shaft is 1.06 but the inside of the bearing is 1.057. As such, the bearing will not slide on the shaft. I don’t know which one is out of spec.

I bought the inner bearings quite a while ago (the are dated 2012 on the label). They don’t have sealed bearings and it appears that the new versions do. I am going to have to do something to get them to fit. I might give Texas Ts a call and see what they can tell me about what I should do.

[Scott_Conger]

I doubt the measurement on the bearing. I would believe 1.0623 but not 1.0570.

Calipers are not adequate for this job if that is what you're using. In any event, whatever you're using, I'd calibrate against a known standard and ensure an accurate reading within the capability of the device. With bearings, you want to be able to repeatably and reliably measure to 4 decimal places.

FWIW, I think those inner bearings are roller bearings, not ball bearings, not that it matters to you, but from a design standpoint, it does. From the title, I thought I was going to be seeing some sort of new product.

[Reno Speedster]

I measured it again with my Sterrett micrometer, which showed the axle as 1.062. I get almost exactly the same for the inside of the bearing, but the bearing will not slip over the axle. I read the instructions that came with the bearings and they say that the axles need to be turned to 1.06. I have to say, that’s pretty annoying. I can probably take a couple of thousandths off on the lathe. I wonder how that will impact the fit of the gears?

[Humblej]

I agree with Allen. I see no advantage to change from the original hyatt bearings for the inner axle and given the fit issues with the new style bearings, see only disadvantages to do so.

[Mark Gregush]

Check the outers too, you may see the same size issue.

[Scott_Conger]

Morgan

if you look at the instructions again, I think you're going to find that the "1.06" turning is BETWEEN the bearing surfaces so as to keep you from having to push the bearing along the ENTIRE length of the axle shaft. You would NOT turn down the area for the bearing nor the keyed gear.

And I'd repeat: calipers are not a measuring device for 4 decimal places. With proper measuring equipment, I am certain that you're going to find that the bearing ID is around 2 tenths smaller than the axle. With that said, I very much suspect that if the center portion of the axle was turned slightly undersized for clearance, then with chilling the axle and heating the bearing to around 175F, I would bet that the bearing would all but fall onto the axle once aligned.

Sounds like you're beginning to doubt whether or not all of this is worth it, to upgrade from Hyatts. If so, then I'd say we were in agreement.

[Reno Speedster]

The new axles are fully machined and are the same diameter their entire length. I got them and the safety hubs from Texas T Parts. The safety hubs fit on the axles perfectly, which makes me suspect it could be an issue with the inner bearings.

I am a machinist and have good/accurate measuring equipment capable of measuring to tenths of thousandths. Getting accurate measurements on the inside of things is tricky sometimes, but the salient fact is that the inner bearings don’t fit over the axle.

I could run Hyatt bearings, but I like the more modern bearings. I will work it out.

[Scott_Conger]

I'm not immune to beating a dead horse, I suppose. If there was a doubt, this should remove it.

You've measured the bearings at 1.057 and now 1.06 "but won't go over the shaft"...a shaft that measures 1.060. You're guessing that the bearings are made wrong, but still do not know what they actually measure in tenths, all the while saying you have equipment that will do just that.

I suppose that I'm missing something, since with your experience and tools, I would expect that at this point, you'd know EXACTLY what the shaft measures, in tenths, and EXACTLY what the bearings measure in tenths, and then know EXACTLY what you need to do to either make them fit, or find their way into the trash.

I just rebuilt a lathe motor where I had to pull the bearings off with a puller...it was not easy, and the new bearings were too small to go onto the shaft. Yet, when it came time to do the final assembly, the bearings fell onto the shaft with no modifications to either the shaft or bearings. Go figure.

Good luck with your project. I don't think this issue is going to be solved on the forum...it's going to be solved in your shop.

[Jerry VanOoteghem]

What are the bearing numbers?

[Art M]

Even in the unlikely event that the mounting fits are optimal, I have serious doubts about the bearings having a very long life. The axel shaft to housing misalignment is very high due to shaft flex. And, the dynamic capacity of the ball bearing has to be very low for this application.

Art Mirtes

[Reno Speedster]

I took some time today to speak to the folks at Snyder’s (where I got the bearings) and Texas T Parts (where I got the Axles) about this issue. Very nice and helpful folks. This appears to be an issue with all these bearings. The current instructions for the bearings (which are slightly different than the instructions that came with mine) state that the axle shaft has to be turned down to 1.061 to work in the bearings. My axles currently measure 1.062. I am waiting for a call from the technical expert at Texas Parts to discuss the details, but I was told that the best approach is to chuck the axle in the lathe with a live center supporting the outside end then carefully use sandpaper to reduce the diameter of the shaft. Trying to reduce something exactly 1/1000 of an inch and get a polished surface is a challenge. I was told not to just grind the shaft to 1.061, because there is enough variation in the bearings that this may be too small and introduce play between the axle and inner bearing race. A careful and slow process with frequent stops to try fitting the bearing on the axle was recommended as the way to go. Still looking into the options, and I may decide to just use Hyatt bearings for the inside bearings. The safety hubs work perfectly and my axles are already cut for them, so I will be using them.

[speedytinc]

Looks like a lot of unnecessary work, cost & grief to "Improve/perfect" a model T rear end. How did 15 million T's operate before this improvement came along? I would not have considered this conversion before your account, now I am sure I never will. If a customer ever requests this, Ill just have a good laugh. I would be more concerned with breaking an axle after this conversion removes the support/flexibility of a hyatt bearing. Your 2 housings line up perfectly? you confirmed this with a solid false, full length bar? Safety hubs - the wheels wont come off. Better have a good set of R/M brakes.

[Reno Speedster]

Well, it’s a speedster, so the point is to “improve” the T and make it faster. I have a Muncie auxiliary transmission so I will have Rocky Mountain Brakes. I have never thought of the wheel falling off when the axle breaks as a feature, but I guess it would bring you to a stop eventually. But wouldn’t you still loose your brakes if that happened?

Back in the 20s, they made a much more robust ball bearing system to support the differential for use in race cars and speedsters, but it included an entirely new differential housing. Sadly no longer available.

This is hardly the most challenging problem I have faced building my car and I will get it worked out.

[Dan McEachern]

The only sound upgrade for the inner bearings in a T rear end is to move the carrier support bearings off the axels and onto the carrier itself and the housings. Ford realized this with the change in the Model A rear end. Given that tapered roller bearings were just being introduced around 1908, its not surprising that Ford used the Hyatt and thrust washer design that was carried through production.

Installing tapered roller bearings in a T rear end requires a fair amount of machine work, but the result is a very nice running rear end.

Short of this, run the stock Hyatt bearings, you will save yourself a lot of grief and also the very real possibility of yanking it all out at a later date.

[Reno Speedster]

Still looking into the options. I don’t think I have any Hyatt bearings in my pile of T parts, but I need to check. I understand the currently available ones are not good. Converting things to tapered roller bearings would be fun and could be a cool long term project, maybe for the next car.

[Art M]

I think that the roller bearings from synders will work. They require ay least .005 inch radial play. .010 inch would be better.

Art Mirtes