Risk in welding to the axle

Mr Rehab

Traveller
Travelling northern Argentina and the hanger for the rear shock absorber has broken the welds to the axle. I've been reading that its possible to warp the axle when welding. I know nothing about welding so my questions..

What tips do you have for avoiding this risk?

Is it really a problem with such a heavy axle?

The truck is a 2010 Isuzu NPS (Aust spec) with R066 6600kg rated axle.

We're heading for Buenos Aires with another 10days before flying out. The truck is driving fine, we've just travelled 100km on rough dirt roads and I couldn't tell the difference....which probably means its time for new shocks but one problem at a time!

Comments appreciated.
 

unkamonkey

Explorer
If you look at welds done at the factory, nobody was concerned about warping things. I'm not a certified welder but a welding inspector said I could weld well enough to be certified. Your welder needs to let things cool off a bit before they continue for the entire weld.
 

v_man

Explorer
If you're just repairing a broken shock mount, that should be a pretty quick fix. Since you're not introducing a ton of heat for an extended period of time, you likely run very little risk of warping anything.

FWIW, I'd be more concerned about some of the seals in the axle. Do you plan on removing the shafts and draining any gear oil?
 
Re-welding the tab back on is very straightforward. You don't have to be that accurate as the bushes will allow for movement. I would be careful who welds it, they do need to be careful with heat, you can damage and axle with too much heat. I would remove the Axle from the side your welding, The heat can raise pressure inside the axle tube, and the axle should not be subject to high heat as it is tempered. Do the weld slowly and keep the area cool. I'm assuming they're using an arc welder.
Disclaimer, I'm not a professional welder I learned my welding in the bush of Africa.
 

pugslyyy

Expedition Vehicle Engineer Guy
This is a very simple repair. As long as the welder doesn't use a couple for batteries in series, jumper cables, and a coat hanger as his welding rig you will be fine.

Sent from my SM-G935V using Tapatalk
 

Theoretician

Adventurer
Depends on whether you're planning a short term fix to get you to a shop after babying the rig, or a long term fix intended to maintain reliable operation over a long term.

For the short term, you should be fine so long as you're careful about heat building up in the axle itself rather than the axle shaft tube that you're welding to. You might want to remove the axle shaft on that side and replace the oil afterward, but that might be overkill.

Long term I might worry about the damage to any heat treatment based performance characteristics in the area of the weld. Check the weld for signs of failure, and the tube for signs of deformation, before any big trips and after any hard days and you shouldn't be surprised by a failure. I think that I'd rather return the tube to factory spec by replacing it as soon as possible than let a concern fester.
 

stingray1300

Explorer
I am a certified (structural) welder. Have been for over 30 years. I've done a lot of repair jobs on trucks and trailers, frames, axle tubes, etc. If you find a qualified welder, you should absolutely nothing to worry about. You will probably hear all manner of "precautions", almost none of them are based on any reality.
.
You do not have to remove the axle. The heat will not transfer to the axle from the tube. If the welder you choose uses the MIG process, the weld gets put down too fast for too much heat to build up. (ever welded on a "live" gas pipeline? - gets done all the time.... safely)
.
The ONLY 2 precautions you have to be concerned about is 1- weld are must be perfectly clean, and should be lightly grinded (even a Dremel drill); and 2- make sure the ground lead gets attached as close to the weld point as conceivably possible. I might suggest a muffler shop if you're in a less urban area. They usually can handle a job like this.
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If you're in/coming through the SF Bay Area, c'mon by and I'll slap it together for ya for nuthin'. PM me if you have any questions.
 

SkiFreak

Crazy Person
If you find a qualified welder, you should absolutely nothing to worry about.

I agree with this statement 100%.
If you use a certified welder, and you should, then they will know exactly what is required for a professional job.

When ATW did a replacement of my front coil supports, which was a much larger job than you are talking about, they did not remove the axle. As explained by stingray1300, it's just not necessary.
 

Mr Rehab

Traveller
Thanks for all the prompt and quality advice gents.

I should have added that I'll be looking for a good truck workshop and my 'passion fingers' won't be anywhere near the job. Unfortunately we've had several expensive bad repair jobs done by people who should have known better so I've learnt the better informed I am the better I can provide some guidance or intervene if necessary.

Stingray1300, thanks for the offer but we'll be heading south to Ushuaia in Dec then slowly north to your vicinity in a couple of years. Maybe I'll have some more work for you by then.....
 

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