Trailer wheel bearing seals

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  #1  
Old 10-05-17, 01:43 AM
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Trailer wheel bearing seals

Just wondering which way around the seals in an NTN bearing kit are supposed to go. I read the instructions carefully - "Make sure the seal lips are pointing in the correct direction"... Thanks a lot!

This is the seal and cup - and the way I think the seal is supposed to go! (Lip pointing towards bearing - other wheels seal+cup upside-down in my left hand)
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This is how the old seal came off the wheel (lip facing away from bearing, pressed into cup)
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I saw in the instructions it says use a special tool to press the seal in. So the only way I can think that would require a tool is the way I've done it, and I guess the tool is to fit over the seal and squeeze the lips in so it fits into the cup.

In any case, the seal doesn't really sit against any lip or collar on the spindle, there's nothing to stop it working its way out of the cup. This just how it's supposed to be?
It's altogether now but I'll remove and correct it if I've got it wrong. Hopefully I've got it right??
 
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  #2  
Old 10-05-17, 04:56 AM
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  #3  
Old 10-05-17, 10:25 AM
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There's something else in that assembly to consider. That isn't a conventional seal setup. The pics Pilot has is pretty much standard.

Is that on a rubber torsion axle on a boat trailer maybe. I wouldn't take out on a trip with that just yet. The inner seal lip should seat on the inside spindle shoulder that holds against the inner bearing.

I'm not sure why they made that seal a two piece. The seal looks hat shaped so there's only one way for it to go together. I wonder if that cup isn't stainless steel.

What is the seal kit number?
 
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Old 10-05-17, 11:25 AM
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That seal pilot shows was on the right wheel, would have been great if that was in the kit as that makes sense!

The cup is hat shaped, the only way it makes any kind of sense is driven into the hub like that. There's no room under the cup so it either goes with the lip pointing outwards or inwards, on top of it. Here is a photo of the spindle with wheel installed, you'll see what I mean when I say no matter which way you install it it is only ever really held in place by friction.
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The bearing doesn't sit against a collar or lip too I believe the inner diameter of the bearing itself was tapered and it just snugs up on the tapers spindle.

I think it was in backwards. They probably put the apprentice on it when it went in last time and that might be why it was starting to fail. When the wheel came off the cup and seal were stuck to the spindle I don't even think it was driven into the hub.

Kit is below. Looks like a sticker over a sticker not sure who has put what/where. We are on the road as we speak, found a rumbly bearing last night before our trip north to new section today. Lots of helping hands coming so it's got to open today. What is life without a little risk...

Thanks for replies
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Old 10-05-17, 11:28 AM
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One more of the spindle with a better view.

And it's not a boat trailer just a flat deck
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  #6  
Old 10-05-17, 03:40 PM
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I see what you have. I wouldn't be a proponent of that setup. They are using the tapered fit of the inside bearing race against the spindle as a sealing surface, which isn't a good idea since you need a tolerance to the hub bearing fit for the bearing to work. That tolerance is critical to prevent overheating and wear. The torque value on the spindle nut would be critical.

Even so it would be hard to keep that inner bearing tight. I'm reading this as the seal is seating against the bearing race, then?

If the cup is pressed in properly and it has a divet or type of bulge in there for the seal to press into, that would hold it in place. With the hat shape configuration of the seal, there is only one way for it to go in.

That is a different little animal, though.
 

Last edited by marbobj; 10-05-17 at 03:59 PM.
  #7  
Old 10-05-17, 06:02 PM
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That may very well be a "Never Lube" hub. It sounds like a great idea, but expecting the bearings to last forever or the lubricant may be expecting a little too much. I wouldn't say it doesn't work, well, though.

The tolerance between the bearings would be set differently than a pair of tapered bearings.

I'm not sure when that style of hub/bearing came out for trailers, but it looks like it's predecessor is the automotive hub assembly used with CV axles.
 
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Old 10-06-17, 12:34 AM
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No the seal doesn't touch the tapered bearing. The bearing and races are the type shown in pilots photos.

So I have changed my mind about what is sensible anyway, I don't think the seal was supposed to be pressed into that cup. I found after a short while driving the seal has obviously been spinning with the cup and the spindle was starting to chew out the centre of the seal. I talked to someone who had done a seal like this before they said you fit the seal to the spindle before the hub goes on, and then press the wheel hub up against it, with the cup fitted into the hub. The seal has a sort of rim that slips inside the cup and then the outer lip fits over the rim of the cup, and rubs around it as the wheel spins. Makes a lot more sense and looks better than it did before.

I'll have to ask the auto shop what the standard practice is next time I'm down there.

I'd never actually replaced races before, I gave them a couple of hard hits with a drift and though F*** it what have I gotten into. While reading up on it I saw a guy who used an air cold chisel to drive them out. Happened to have one in the drawer - they are awesome for doing this, FYI! Took about a half second blip at 12, 3, 6, and 9 o'clock on the race and it was on the floor.
 
  #9  
Old 10-06-17, 03:41 AM
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I hope it works out for you, Josh. I've never seen that setup on a trailer axle. I can't place the tapered spindle instead of a solid shoulder. There may be some production reasons or it may just be to make parts proprietary. Googling only brought up the Never Lube jobs.

That seal setup isn't too impressive. I wonder if that is an OEM trailer or something someone put together with on hand parts. Square tubing isn't a real popular cross member for an axle since it doesn't flex like round tubing. The five bolt hub is used in the 2500 to 3500 lb axle so you can have some weight there.
 
  #10  
Old 10-06-17, 09:13 PM
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Well looking a little deeper on your hub. A hub that uses that seal setup is a Trojan hub from New Zealand. They're distributed along with a number of other trailer parts and accessories. That could be an exclusive distributor that sells OEM, wholesale and retail.

The seal setup, though is a head scratcher since it doesn't really put anything together solid. If you simply pushed the seal on the spindle with nothing to locate and hold on the spindle the seal would simply work its way away from the hub. That brings you back to pressing the seal into the cup and the cup being pressed into the hub. That setup would work but the seal would have to have a solid fit to the hub through being pressed into the cup.

Making that type of seal makes no sense. The one piece seal Pilot is showing at the bottom of his pics is a better design.

There is a little physics that comes into play here. A seal is normally held to rotate with the hub at its largest diameter and interfaces with what it rotates against at the smaller. In other words the fixed part has leverage on the moving interface. That way the seal is held tight in the hub and you lube up the seal mating surface on the spindle and the seal can't work up the spindle away from the hub.

If the design you have is having the seal against the spindle to hold tight while the moving parts are on the hub what will likely happen, unless the seal fits very tight on the spindle, is the seal will turn on the spindle and move away from the hub.
 
  #11  
Old 10-07-17, 02:56 AM
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I agree with you marbobj, doesn't seem ideal. I've not had much to do with the trailer so couldn't comment on its lifespan or anything. All I can say is wheel that had this seal had the rumbling bearing, but, it was installed incorrectly.

I did talk to the guy in the auto store today, he confirmed my thoughts in post #8, where the seal is pressed onto the spindle and the outer lip rubs against the steel cups rim. Also said they've been around forever and work fine. I don't see why it won't work its way away from the hub as you said. Time will tell.

Thanks a lot for your help anyway!
 
  #12  
Old 10-07-17, 05:48 AM
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I didn't note you were from Canada. You probably have different parts up there to work with. That would explain sources from New Zealand.

But if it's worked before there must be something there that gets the job done.

Best of luck to you.
 
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Old 10-07-17, 05:54 AM
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I'm back and forth between Canada and New Zealand, I probably started this account while over there, but the trailer is in NZ this time. I'll report back when it fails, if I remember haha!

Thanks again.
 
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