Welding suspension components

[stewy]

So I know welding 'highly stressed components' is a no-no as far as MOT tests are concerned. But I'm curious if this is a general rule to simplify the test regulations and whether welding such parts always constitutes a serious risk.

I'm thinking specifically of things like lower wishbones and spring pans that typically rust through. They seem like the sort of thing which, if they developed a tiny hole could be welded up quite effectively. But of course it's probably pretty hard to determine if doing so would compromise the original integrity / properties of the component.

Does anyone have knowledge / experience of how it is decided what constitutes safe or unsafe repairs specifically relating to these kinds of parts and the engineering behind it?

 

[ajlelectronics]

So I know welding 'highly stressed components' is a no-no as far as MOT tests are concerned. But I'm curious if this is a general rule to simplify the test regulations and whether welding such parts always constitutes a serious risk.

I'm thinking specifically of things like lower wishbones and spring pans that typically rust through. They seem like the sort of thing which, if they developed a tiny hole could be welded up quite effectively. But of course it's probably pretty hard to determine if doing so would compromise the original integrity / properties of the component.

Does anyone have knowledge / experience of how it is decided what constitutes safe or unsafe repairs specifically relating to these kinds of parts and the engineering behind it?

If you are capable of doing a good, strong repair then my advice would be to make it invisible. A freshly painted but good spring pan would not wave any flags.

 

[Woody.v8]

My take on it is if its done correctly there is no issue .
Suspension components are usually welded badly in the first place by unskilled operatives so a repair by a skilled person is not going to make the components fail.

 

[minimutly]

I made a pair of lower spring platforms for the rear of my Jag xf last week - better gauge and machined Snapring locators too. Will hopefully see the rest of the car out. Welded mini bottom arms have been used and abused for years.
Standby for tirade of "if you're in an accident you will be burned at the stake" expert comments, which may have some merit, but if you've done the job right no worries.

 

[m_c]

So I know welding 'highly stressed components' is a no-no as far as MOT tests are concerned. But I'm curious if this is a general rule to simplify the test regulations and whether welding such parts always constitutes a serious risk.

I'm thinking specifically of things like lower wishbones and spring pans that typically rust through. They seem like the sort of thing which, if they developed a tiny hole could be welded up quite effectively. But of course it's probably pretty hard to determine if doing so would compromise the original integrity / properties of the component.

Does anyone have knowledge / experience of how it is decided what constitutes safe or unsafe repairs specifically relating to these kinds of parts and the engineering behind it?

It's ultimately a catch all to eliminate any ambiguity as to whether any particular component can be safely repaired.
The big issue is most suspension components aren't made from generic mild steel, so even if a repair looks good, how can a tester determine if it's been repaired satisfactorily?

 

[minimutly]

It's ultimately a catch all to eliminate any ambiguity as to whether any particular component can be safely repaired.
The big issue is most suspension components aren't made from generic mild steel, so even if a repair looks good, how can a tester determine if it's been repaired satisfactorily?

Well I dunno, hubs and drive flanges maybe, but bottom (and rust prone top ones too) arms (except mini ones) pressed steel, subframes shaped steel, tie rods something better than mild steel maybe. You wouldn't want to weld anything that has any bending force on it, but most other stuff would be ok?
Guy brought me a Pugeot 205 strut with the ball joint clamp broken open once - flat no was the answer..
OTOH my MGZS rally car has modified Cavalier Monroe shocks inside the strut cases - yes you'guessed it, the threaded top of an Astra strut welded onto the Rover one.
And is a modification and repair the same thing, especially if it's a rust repair?

 

[m_c]

Well I dunno, hubs and drive flanges maybe, but bottom (and rust prone top ones too) arms (except mini ones) pressed steel, subframes shaped steel, tie rods something better than mild steel maybe. You wouldn't want to weld anything that has any bending force on it, but most other stuff would be ok?
Guy brought me a Pugeot 205 strut with the ball joint clamp broken open once - flat no was the answer..
OTOH my MGZS rally car has modified Cavalier Monroe shocks inside the strut cases - yes you'guessed it, the threaded top of an Astra strut welded onto the Rover one.
And is a modification and repair the same thing, especially if it's a rust repair?

Bottom arms and subframes aren't mild steel.
Even pressed mild steel will buckle quite easily at the typical thicknesses used for such components.

 

[minimutly]

Vauxhall Astra, early Cavalier, mgF, all mild steel pressings, or at least behave as such.
My MGZT (and current Jaguar) are aloominium. The mG6 is a forged steel shorter copy of the MGZT

 

[zzr1200]

I've cut and welded a steering drop in the process of converting a RHD non-powered steering CJ7 into one with power steering. Including modifing the drag link to take a Triumph 2.5 pi ball joint, to match the bottom of the drag link taper.

 

[Erie Fred]

Do you apply your stamp next to each weld ?

 

[Ubique]

Vauxhall Astra, early Cavalier, mgF, all mild steel pressings, or at least behave as such.
My MGZT (and current Jaguar) are aloominium. The mG6 is a forged steel shorter copy of the MGZT

Most pressed steel suspension components will be HCS or AHSS. Don't expect to apply the same techniques or consumables to welding AHSS as you would to MS.
Edit:- here's a particular type of AHSS used for pressed & welded suspension wishbones by some manufacturers https://steelprogroup.com/automotive-steel/hsla-hc500la-coils/

 

[Morris]

Most pressed steel suspension components will be HCS or AHSS. Don't expect to apply the same techniques or consumables to welding AHSS as you would to MS.
Edit:- here's a particular type of AHSS used for pressed & welded suspension wishbones by some manufacturers https://steelprogroup.com/automotive-steel/hsla-hc500la-coils/

It's not that far removed from what a lot of people on here are used to though.

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://ssab-docol.octoapps.com/content/media/en-Docol-Welding-handbook.pdf&ved=2ahUKEwixmtXntuGLAxXVX0EAHS_nA0kQFnoECFoQAQ&sqi=2&usg=AOvVaw3m2t6_E55w-NHL_-NpsttP

 

[Ubique]

No it isn't, but you need to know the difference and use vehicle manufacturers data to identify the components that are not LCS then treat accordingly.

 

[ajlelectronics]

No it isn't, but you need to know the difference and use vehicle manufacturers data to identify the components that are not LCS then treat accordingly.

How glad I am that my work involves just one, elderly marque!

 

[Ubique]

How glad am I that manufacturer approved bodyshops deal with all that stuff for us! I have a colour coded schematic of a Volvo somewhere that shows all the different types, it looks like a couple of NHS rainbow flags have been tied into a Gordian knot!

 

[colnerov]

And of course the MOT guidelines just say inappropriate welding of steering and suspension is a 'reason for failure' leaving it down to the tester to judge with of course no back up from the ministry.

 

[Matchless]

I made a pair of lower spring platforms for the rear of my Jag xf last week - better gauge and machined Snapring locators too. Will hopefully see the rest of the car out. Welded mini bottom arms have been used and abused for years.
Standby for tirade of "if you're in an accident you will be burned at the stake" expert comments, which may have some merit, but if you've done the job right no worries.

50 years ago I used to cut and lengthen Mini bottom arms for rallying, crashed a few times and they never broke, may have bent a lot, that was using an Oxford oil cooled stick welder and rods my father had brought home from Fuller Electric transformers in Walthamstow.

 

[EEEK]

Say you have a rotten hole in a suspension arm/sub frame that you've just found on your pre mot check . Still driving fine and the wheel hasn't fallen off and could have been there for 11 months. You weld it up with a bit of "wrong" steel, surely it must be better and stronger than the hole

 

[Ubique]

Say you have a rotten hole in a suspension arm that you've just found on your pre mot check . Still driving fine and the wheel hasn't fallen off and could have been there for 11 months. You weld it up with a bit of "wrong" steel, surely it must be better and stronger than the hole

Ask your insurer that question.

 

[Morris]

Just had a look, AHSS wasn't used until early 90's. Prior to that who knows what it was made of.
I do know that I have made my own suspension parts, starting in the early 70's, for hot rods and heavily modified stuff. This includes wishbones, axles, steering arms and other steering components. The number of failures - none. Number of times it was questioned at MOT- none.