Disappearing U-bolts

[Pedro_The_Swift]

I can sort of see one set of double nuts maybe vibrating loose, or nearly maybe one u-bolt snapping. But neither of these will make both u-bolts vanish...

Is this normal for trailer axle u-bolts?

[Saitch]

Perhaps the composition of the u-bolts, i.e. country of manufacture, may come in to play here. Is this on the 'van, Pedro?

[trout1105]

I can sort of see one set of double nuts maybe vibrating loose, or nearly maybe one u-bolt snapping. But neither of these will make both u-bolts vanish...

Is this normal for trailer axle u-bolts?

IF the U bolts have been over tightened it is common for them to fail, Loxens will stop them from vibrating loose and falling off as well.
If one set has failed I personally would be replacing ALL of them with new ones [thumbsupbig]

[Pedro_The_Swift]

Yes, drivers side rear,,,,



Yep, even Mrs Pedro is now concerned about the others,,,

also that "-the wheels are held on by only 4 bolts???"

[bigrolf]

[scarry]

Nulock nuts will sort them,but they should be a one use item.

[p38arover]

IF the U bolts have been over tightened it is common for them to fail, Loxens will stop them from vibrating loose and falling off as well.
If one set has failed I personally would be replacing ALL of them with new ones [thumbsupbig]

Loxen? The drug for those of us with angina? :)

[V8Ian]

What is a Loxin?




The Loxin is a shorter length thin wall internally threaded expansion anchor for weaker substrates such as brick, block and stone. For fixing to. Concrete, brickwork, blockwork. Features. Flush setting no protrusions when not in use.

[Aaron IIA]

Did the original bolts have spring washers? If these get a little loose then the nut will work off. The u-bolt may stretch, resulting in the spring washer no longer holding the nut tight enough. Spring washers are prone to breaking. This results in failure of the locking mechanism. Use nyloc nuts. Even if the u-bolt stretches, nyloc nuts will not further undo.

Aaron

[Slunnie]

Yes, drivers side rear,,,,



Yep, even Mrs Pedro is now concerned about the others,,,

also that "-the wheels are held on by only 4 bolts???"

[bigrolf]

I hope she doesn't notice the hub is held on by only 1 bolt!

[trout1105]

Loxen? The drug for those of us with angina? :)

I'm a bloke so I don't have one of them[bigwhistle][bigrolf]

[350RRC]

Nulock nuts will sort them,but they should be a one use item.

I know of people who get double duty out of them by gently tapping the 'cap' on the nylon part with an American screwdriver (my mechanical genius grandfather's name for a hammer).

Works for me, but 'don't try this at home'.

DL

[scarry]

I know of people who get double duty out of them by gently tapping the 'cap' on the nylon part with an American screwdriver (my mechanical genius grandfather's name for a hammer).

Works for me, but 'don't try this at home'.

DL

We do that at work on occasions,but on something where they are used as a critical component,we always only use them once.

Crankshaft nut for a flywheel is a good example.
And use a torque wrench.

[350RRC]

Yeah, I only do it on the little ones. It's not as if they're expensive.

DL

[BMKal]

I use "Nord-lock" washers on trailer suspension U bolts, with Nyloc nuts for added safety. I learnt the hard way after having to rescue a friend a while back when his trailer and axle parted company on one side coming back from Wave Rock to Kalgoorlie on a weekend camping trip. I managed to hold his trailer together with fencing wire for long enough to get it home, and then we fitted all new U bolts with Nord-locks and Nyloc nuts. I never use "spring washers" for anything - they are crap.

I learnt about "Nord-lock" washers while working with crushers for years. The vibration experienced in these machines will shake anything loose - except for Nord-locks. I now always keep a box of various sizes in the shed and still use them regularly. You can get them at any decent fasteners supplier - such as Blackwoods - (I won't use the cheap Chinese copy of these that Bunnings flogs).

https://www.blackwoods.com.au/fasteners-fixings/washers/washers-serrated-nord-lock-zinc-plated-and-stainless-steel/c/307061227/208638195/variants

[POD]

I've seen enough broken U-bolts that when I built my camper trailer I was having none of them, came up with a far better solution using clamp plates and HT bolts. 21 years and many thousands of outback km and every time I check them they are still snug.
181446

[ramblingboy42]

youre on the money here Pod.

as I read further into the thread. I thought why doesnt any one use plates and hi tensile bolts and there you go.

[Lionelgee]

Hello All,

Back in 2019 I bought a brand new dual axle trailer. In my second week of ownership the trailer came to a dramatic stop after the rear axle passenger side U-bolts disappeared and the axle moved backwards onto the chassis. After parking the car and trailer off the side of the highway I walked along the road behind the trailer picking up leaf springs. After I continued the walk further down the road I found one of the U - bolts. It had broken off at a bend where the bolt changed direction. It had pinch marks where the bend must have been forced by a die when it was manufactured. The u-bolt broke off at the pinch. Once I got into town I went to a trailer supplier and all their u-bolts had the same die-formed pinch. I bought a complete set of larger diameter of u-bolts that were a different brand for the trailer - ones without the pinch. The trailer has had no troubles since then.

Kind regards
Lionel

[Dorian]

Hello All,

Back in 2019 I bought a brand new dual axle trailer. In my second week of ownership the trailer came to a dramatic stop after the rear axle passenger side U-bolts disappeared and the axle moved backwards onto the chassis. After parking the car and trailer off the side of the highway I walked along the road behind the trailer picking up leaf springs. After I continued the walk further down the road I found one of the U - bolts. It had broken off at a bend where the bolt changed direction. It had pinch marks where the bend must have been forced by a die when it was manufactured. The u-bolt broke off at the pinch. Once I got into town I went to a trailer supplier and all their u-bolts had the same die-formed pinch. I bought a complete set of larger diameter of u-bolts that were a different brand for the trailer - ones without the pinch. The trailer has had no troubles since then.

Kind regards
Lionel

X 2
I had the same sort of problems with a small trailer, the Ubolt looked more like a V than a U. I noticed one of the bolts had broken when I had to change a flat. Trailer had done barely a 1k. As I had a round axle I replaced them with a set of "proper" UBolts just from the local hardware store, 15 years later I've not had any problems.

Cheers Glen

[vnx205]

For the benefit of anyone else who, like me, had never heard of Nord-Locks, the following video shows how they work.

Nord-Lock Wedge-Locking Washers - Junker Vibration Test - YouTube (https://youtu.be/IKwWu2w1gGk)

[DoubleChevron]

Well I just gave the wheels a kick on the old trailer here before it was hooked up and thought "hmm, loose wheel bearings"... but they field good ... weird .... So I shook the entire trailer and it moved against the axle....... Ohhhh..... I had a look under it ... every "U" bolt is loose :o ..... I'm betting they are all stretched. I "might" have accidentaly [bigwhistle][bigwhistle][bigwhistle] massively overloaded it one or twice ... or maybe 100 times. I'm going to replace htem not tighten them as I reckon they are now unsafe for use.

Have you massively overloaded the trailer lately ? (or lent it to anyone ).

seeya,
shane L.