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Bedtime Story/Something for the Winter?

Posted: Wed, 21 Oct 2009, 9:43 pm
by txfsealord
Many years ago, long before we bought our Ansfold, I was following a car towing an old caravan on a dual carriageway in the right-hand lane, approaching a roundabout. I'd just noticed the 'van's offside wheel wobbling, when the wheel came off altogether & the right side of the 'van hit the road! Its folded rear corner-stay made an excellent tarmac planer, digging in & bringing the remains to a shattering halt in the middle of the right-hand lane. I just managed to swerve in time to avoid a very close check of their internal decor!

Not much of a 'story' really, 'cos it actually happened. I was servicing a trailer at work today, & the hub design brought the above to mind.

Trailer & caravan hubs all use adjustable taper roller bearings these days. The adjusting nut cannot be tightened, as this overloads the bearings. The nut is locked with a split pin. When this construction is used on car hubs, there is always a keyed washer behind the nut, so bearing rotation can't be communicated to the hub nut. I don't know of any civilian trailer axles which have this keyed washer; certainly ours have not.

When I overhauled my axle, I drilled out the 9/64" splitpin holes to 11/64" & used a bigger pin. I also opened the pin in the 'aircraft' way, i.e. both legs bent round the nut & tucked in the adjacent castellations. This has a better shearing-resistance.

The accident described was caused by the nut either having been overtightened & the bearings failing through heat, or (more likely) normal rotation of the outer bearing on the stub-axle shearing a weak splitpin.

The 'van was a write-off, & it had taken root in the road in a very dangerous situation. Don't let it happen to you.

Steve Lord

Posted: Thu, 22 Oct 2009, 9:23 am
by bigbird
Good advice Steve, I'll show this to OH owner of the tool box in this house!

Re: Bedtime Story/Something for the Winter?

Posted: Wed, 02 Jun 2010, 7:08 pm
by txfsealord
Ansfoldsplitpin.jpg
Hi all,

I was servicing my van & I took a pic of the "aircraft" type of splitpin fitting, which I use on my hub nuts. It gives improved shearing resistance, & a further bonus is reduced protrusion into the grease cap. So if (like me) you use non-standard wheels & hub caps, this allows you to flatten the grease caps by peening them closer to the axle ends. And doing this made just enough room in my case for the Mini hub-cap fitting, when allied to the cap-deepening process referred to elsewhere on here.

Steve