Trailer bearings.....axle

5 years 2 months ago #26070 by scubaal
scubaal created the topic: Trailer bearings.....axle
I've read about 200 posts about trailer bearings across the net but can't find anything that answers this....
Three weeks ago I had a bearing fail on my trailer. Very nasty and lucky it didn't kill us. It died in the driveway after a 250km drive at 100kmh!
So luck was with us. The unlucky bit was that the bearing failing also wrecked the end of the axle. So new axle. The trailer is a Southern Cross make with a 45mm square solid axle with SL bearings. Ordered a new axle from local trailer place after leaving the old one with them for a template and waited three weeks for it to come.
When it arrived everything lined up perfectly and I bolted it back in with new bearings, seals etc.

It was only after I wa all put together that I noticed a difference between the old axle and the new. The issue is, I don't know if its important or not?
All diameters of the machined ends are the same. All bearings fit perfectly however on the old axle the inward machined area where the rear seal sits is 25mm deep. On the new axle this machined area is 13mm deep, ie there is 13mm of machined circular metal before the square section of the axle starts. So what difference Does this make to the fit up? Well, with the old axle when the marine seal is nicely seated in the back of the axle there is a 10mm gaps of round metal before the square bits starts. On the new axle there is no gap - the square material is flush up against the seal, and when everything is tightened down with the hub on the seal is slightly compressed between the hub and the square of the axle. Initially I thought this was a problem because the seal would rotate.....and get wrecked by the edges. But it now seems that in both cases (old and new) the neoprene seal stays put on the axle and the stainless insert in the hub rotates around the seal?
So may be its not an issue.

Is there anyone out there who can comment from experience? Anyone with a 45mm square axle where the seal sits on a gap exactly its own width? Has it caused any problems (it could even be better as the seal can't pop out of the back of the axle) if I can't be sure it's right I'm gonna take it back next week but that's a real pain so wouldn't want to do it if someone can tell be the new setup is ok?

Thanks
Al

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5 years 2 months ago #293517 by slug
slug replied the topic: Trailer bearings.....axle
From what you describe it sounds ok. The marine seal is designed to stay stationary with the axle and as you noticed the cup rotates with the hub. The only thing I see as a possible problem is the lateral loading on the seal.

I suggest you adjust the wheel bearings with a little preload, then back off a bit until the nut is in contact but only finger tight. Then turn the hub and check how tight the seal is loaded by the hub.
The outer lip should be compressed against the cup but not pressed hard against it causing a tight 'feel'.

I can't describe the correct 'feel' here, but if it feels too tight to you, it probably is.

Just make sure the bearings and seal are well lubricated with a waterproof grease on assembly. (I use a moly. based grease, similar to CV joint grease), it's a bit messy but high performance with good waterproofing qualities.

Cheers.

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5 years 2 months ago #293527 by ovakil
ovakil replied the topic: Trailer bearings.....axle
My axles are the same as your new ones.
When I did my bearings 6 months ago (crap of a job) I put some sealer between seal & axle.

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5 years 2 months ago #293528 by scubaal
scubaal replied the topic: Trailer bearings.....axle
Thanks ovakill so I take it that your rig is ok with that axle?
It did not cause any problems with the seal being a close fit between the hub and the square section?
What sort of sealer did you use?

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5 years 2 months ago #293666 by Skinah
Skinah replied the topic: Trailer bearings.....axle
You can get special hub caps some sold under a brand called 'bearing buddys'. www.bearingbuddy.com

When the bearings are hot from driving and hot days, and then get dunked into cold water they dont suck salt water in. My mate swears by them. Worth looking into.

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5 years 1 month ago #294416 by Peter Huettner
Peter Huettner replied the topic: Trailer bearings.....axle
Marine seals need to be glued to axle so they don't rotate or let water in.

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