Square end U bolts

[Capn Jack]

Guys

My old trailer has Square end U bolts holding the rollers and the axles which are showing signs of flaking rust. From a safety point of view I want to replace them.

I can get the right sizes from Trailertek and a few other places sold as High Tensile with Zinc passivated coating.

The problem is the quality of manufacture....I'll explain. I bought 2 bolts to test the sizing, when I tested them they fitted over the square section but because they curl in at the Square end they would pinch the galvanising when finally tightened. The pictures should show what I mean.

What I would like would be Stainless Steel but I don't think I can get High Tensile in Stainless?? So second best would be Galvanised High Tensile, is that possible??

However, the main thing would be to get the bends as accurate as possible without the 5mm variation. Does any of this make sense?? Or am I spouting gobbledegook here?

[JORIDAPILOT]

Can you put a packer in the end under the box section so that the box is in the full width section. Just a thought

[Capn Jack]

Hmmm, didn't think of that, great idea Paul.

I'm sure there are one's which are made better though, but still a great option, thanks.

[Capn Jack]

Any other idea's on this one? Calling all engineers!!

[salamis]

Capn have you tried indespension in Redhill or failing that I have the number for John Cunningham in Pulborough. If you want his number PM me he has his own engineering business and also has a passion for all things boaty including trailers plus being a really great bloke.

[Capn Jack]

PM sent.

[Gazjen]

What about using galvanised/stainless plates and long bolts with nylocs?

[Capn Jack]

Sounds like a good idea Gaz. I still think that someone must make Square end ubolts which are acurately made.

[Gazjen]

Possibly but how critical are they? if your trailer chassis is sat on top of your axle then the role of the U bolt is just to hold it all in place there not really carrying any excessive load

[Capn Jack]

Possibly but how critical are they?

For replacement or accuracy in make?

You are right, the Suspension units are bolted to the axle frames and the trailer frame sits on top, the ubolts hold it together..

But as you can see from the picture below of the stern swinging arm, they are pretty rusted and although they hold it to the frame, my concern as a non engineer is how safe is it when it's swinging/bouncing around at 60mph. ??

I've been thinking that I may be being a little......anal! However these are the swinging arm roller assembly bolts....

Here's the cut ubolt

And here's the difference, not very clear really in the photo but you should be able to see the difference between the old and new. They are different sizes but the bend should be the same.

[jokaboat]

Not quite the answer that you may want but I could not get u-bolts the right size for my old trailer so I went round to a local workshop and got them to bend some threaded bar to the right fit.

A dob of paint and nobody would be the wiser.

I might even have some of the threaded rod left in the garage

[Gazjen]

Not quite the answer that you may want but I could not get u-bolts the right size for my old trailer so I went round to a local workshop and got them to bend some threaded bar to the right fit.

A dob of paint and nobody would be the wiser.

I might even have some of the threaded rod left in the garage

That's not really a good idea as stock threaded bar is quite soft and wont have been treated/normalised in its reformed state plus the threads hold water and corrode quickly

Capt: I would of thought the U bolts you have found although inaccurate would hold your trailer together fine. If you want to go down the plates and bolts route I could make you your plates but they would have to be painted/galvanised after

[Capn Jack]

You know when I saw that JB had replied I thought he was going to say that he had exactly the right sized U bolts in his garage......

Gaz, I'm coming to the conclusion that you may be right. You know when steel rusts although only microns of the outer surface are lost it appears that almost an inch has gone.....OK so I exaggerate a little, but you know what I mean.

The one's which worry me the most are the swinging arm ones which when being towed have different forces applied. I might clean them off then have a look.

It would be so easy to just cut them all off and bolt on new ones if they had a good Square end bend, that's all it needs, just that, the sizes were spot on apart from that.

[jokaboat]

Sorry, no can do this time. I've got a couple of smaller section ones that I was going to use to mount the spare wheel but I sold the boat.

[betty boop]

for that slight rounded corner capn- could you not just square off the inside curve to 90 deg angle with a grinder? besides you sholdnt be worrying about boats you've got a closed airport to keep you busy - my favourite flight (yes I was plane spotter nerd until recently) good to see it got back OK.