It's this time of year when I get loose nuts...

[Reimotim]

For the past 3 years, I have suffered the same problem...

My nuts go loose.

The castellated hub nuts at the rear need tightening. Why is this? Are my hubs deteriorating? Or the spindles? The split pins stay in place so I know the nuts aren't backing off.

Does anyone else have this problem?

[what2do]

Bizarre but I guess the only thing changing is the weather!

[CJH]

I had the same on the nearside wheel. The hub nut became quite loose while I was away on my hols a couple of weeks after buying the van. The split pin was still in. I had a garage tighten it for me to the proper (very high) torque and they put a new split pin in. About a year later it was loose again, so I had it tightened again and the split pin refitted. I put it down to a collapsing wheel bearing, expecting to have to do something about it very soon.

However, since then it's been fine - no noise, nice and tight. I haven't had it apart (yet) so can't explain it, but my best guess at the moment is that maybe the previous owner had replaced the bearings and hadn't pressed one in far enough (but to be honest I don't even know if that's how you have to fit rear wheel bearings). Maybe the lateral forces while driving have pressed it home gradually. Either way I don't think everything is right with that corner, but while the bearing's quiet and the hub nut's tight I'm not going to worry about it.

[CovKid]

The bearing carriers wear slightly oval over time. That may be the cause - possibly.

[lloydy]

with the pin in it can still loosen by a few mm i reckon. which is enough to loose all the nm. The reason why.... i don't know..

[Reimotim]

Well, whatever the reason, I guess I better get out the scaffold bar and tighten them up!

[lloydy]

Have you actually tried a new nut?

[CJH]

with the pin in it can still loosen by a few mm i reckon. which is enough to loose all the nm. The reason why.... i don't know..

I understood that the tightening procedure is to torque it up, then turn it further till the split pin hole lines up. So loosening a fraction within the bounds of the split pin should still leave it at or above the required torque. In any case, when it's happened to mine, the nut has actually been loose enough to turn by hand! My impression is that it's more to do with what's behind the nut, rather than the nut itself. I've got new nuts though, ready for when I take it apart to see what's going on.

[clift_d]

My guess is, as somebody else has suggested above, that it's the bearings bedding in more. The inner and outer bearings are both cylindrical roller bearings so wear on the bearings is not necessarily going to make them 'shorter', but as they are both pressed in it's possible that they get gradually driven further into the hub. A small bit of movement on both bearings would lead to enough at the nut to make it loose. Why it happens at this time of year I couldn't say. Perhaps warmer weather makes the hub looser on the bearings. Perhaps you're just using the van more.

[silverbullet]

Wrong. One is a ball race and controls endfloat, the other is a roller bearing and carries the majority of the load.
You shouldn't back off a torqued nut to get the pin in, there are two drillings at 90 degrees for this purpose.
The castellated nut is a safety device, it is not there to keep it all tight. That is the purpose of the prevailing torque.
If they come loose after correct torquing and using a new nut (as per the manual) it is most probably because the nut threads have stretched over time and through use, but that should take years under heavy use.

[clift_d]

Wrong. One is a ball race and controls endfloat

I stand corrected.