Cracked control arm (lots of photos)!

[AtomicDog]

For those of you who may have been following my suspension upgrade,

Suspension work begins (or 4 days of folly)!

this should be interesting.

As I was cleaning up a lousy looking weld, I noticed something that was not what I wanted to find. At the tube-tube joint near the front of the control arm, there was a crack. I tried quite a few photos before I got one that you could see what I was seeing.



After removing some more of the weld bead, the extent of the crack became more noticeable, particularly when muddy water began to run out of the widening crack.



Notice the large pit, and just above, the dirty area where the initial crack was leaking muck.



The second crack.



So, now I get to do some welding. I figure that since they MIG welded it, I can too. I would really rather TIG something like this, to keep the heat to a minimum - anybody in Jersey want to bring a unit by? I have TIG torches, thoriated tungsten, gas cups and lenses that I would give you for your trouble. Need anything welded? I am best with stainless and inconel, if that makes a difference...

I'll try to get more photos of the repair in progress.

Anyone ever dealt with this before?

Chris

[jpahemi]

I'm a bit confused here; why would you repair this arm? This is something that, seems to me, should be replaced rather than repaired.
j.p.

[88-diamondblue]

If muddy water is seeping out the inside of the arm is rusted. My thoughts exactly as why you would want to repair this. Used a-arms should be reasonably priced.

[AtomicDog]

88-diamondblue & jpahemi,

Since the other end of the tube is open, it's sure to be dirty inside. The majority of the finish on the control arm was intact, with the exception of any surface that stuck out enough to get any sort of abuse. While this was going on, the interior surfaces were leading a rather easy life.

A used control arm would be suspect, as well. What is there to ensure that the same issue is not a common mode failure of the control arms. My mechanic, whom I only ask to do those things that I cannot do, magnafluxes the control arms when upgrading anti-roll bars for this reason.

If surface rust is the only other problem, why would I not be better off by repairing an otherwise good part? I would replace the control arm only if it were bent. A new part would be the ideal solution, but at $500 each, I could not justify the expense. If I had not just spent $$ for the front Elephant polybronze bushings, the added expense might be justified, as I needed the bushings anyway.

I have the tools. I have the skills (no, not just farm welding... nuclear plant piping system welding). I have an engineering degree. The entire front suspension is removed from my car. Why is now a good time to be timid? If it doesn't work, or if I get the part too hot and it bends, I can still buy another control arm.

So, the short answer - cost, or perhaps personal satisfaction at doing a job better than the factory was willing to do.

Chris

[jpahemi]

Considering your safety is relying on the integrity of this part; $500 doesn't seem unreasonable.

[randywebb]

nuclear plant piping system welding ===> remake the whole arm in Ti

[AtomicDog]

Considering that I had to perform quarterly, x-ray inspected welds for over a decade...

I'm not trying to dissmiss your valid concerns, but do you not have one skill you'd bet your life on?

Chris

[rnln]

I would love to but I am could thousand miles away. maybe in the future

[88-diamondblue]

The only thing that made me question this is "How rusted is the inside of the tube?" Never questioned the weld holding, just if the part was rusted enough to cause weakness. Sounds like you have it under control. Keep us posted.

[Evans, Marv]

Those control arms are pretty thick, thick enough it shouldn't be a problem for the weld. It sounds like you can definitely do the welding and then some. So if welding it makes you feel better, go for it. There are millions (OK maybe a small exageration) of good used ones out there for cheeeep if it doesn't work out.

[Jeff Alton]

Weld it. You know what you are doing, clearly, so do it. The rusty water could have been from those torsion bars you pulled out of there too....

Cheers

[AtomicDog]

Hey Randy,

If I could afford the Ti...I'd buy new stockers and finish the suspension mods.



Chris

[Porsche_monkey]

I would repair it.

[SC-targa]

Just weld it. You won't have any problems.

Jerry

[911 Rod]

Why is the weld broken?
I would be concerned you are band aiding another problem.
I replaced mine last year and had a hard time finding a good one.

[Porsche_monkey]

That's from a 20 year old car that has seen a little bit of vibration over the years. A failed weld should not suprise anyone. News flash: automotive welds are notoriously unreliable, that's why they 'overweld'. But they do NOT do X-ray or any other in-process inspection that will guarantee 100% good output.

As for the 'life and death' issue. It didn't break when it was cracked did it? Seems unlikely he found the crack the day after it started. It's likely been propagating for a while.

[Rouxzy]

AtomicDog,
I too am in the Nuclear field and have seen what a proper weld can do. The weld is not the weak point if done right. Weld it.
Tom

[Porsche_monkey]

Originally posted by Rouxzy
AtomicDog,
I too am in the Nuclear field and have seen what a proper weld can do. The weld is not the weak point if done right. Weld it.
Tom

Fortunately most automotive componenets do not require a proper weld. If they did there would be more death and carnage on the roads. Nuclear components on the other hand....

[AtomicDog]

Rouxzy,

Judging by your location, Seabrook?

As for the update:

By the time I made it to sound metal, things looked like this,



The completed beast!



Now we'll get things back together and see if it works...

BTW, it took me forever as I have a nasty habit of trying to make things look like they would've grown that way, if they could.

Thanks for your time.

Chris

[jpahemi]

Excellent job!
j.p.