going to the dunes first time this year, found a crack in my Arm

J

John@Outfront

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gen 5 934 arms

have cracked before on the inside  and made some gusset kits for the 934 arm, but now a new crack all the way through, maybe time to get a little more serious, just did a quick repair, after glamis come a new gusset.  i have no idea way--i baby this thing!

the two pics in black is a previous crack and the solution was two gussets on the inside of the arm

the pics mainly silver is the new crack on the outer part of the arm

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Parshall gusset created a stress riser area at the end of the weld. Even if the welds were past the gusset and crow footed out most likely would have happened.  Weld past  gusset and blend in w/ grinder flapper wheel to nothing.

 
I have a spare right side arm I'll sell you. Came off a clients G52 when he broke the left side and had two new arms built.

 
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L.R.S. said:
I have a spare right side arm I'll sell you. Came off a clients G52 when he broke the left side and had two new arms built.
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Thanks for the offer but my arms had custom pivots at my request. Each pivot has twin uniballs per pivot with seals on outside. These uniballs always go bad. Mine have never been replaced. After I rework this area of my arm it will be better than new

 
You still have 3 tubes connecting it together! Drive it like you stole it and fix it when you get back home! :lol:  

Been there done that. Had Dario make me some new ones with solid gusseting and the next thicker tubing. No more cracks on my car.

They always crack where those curved gussets end. 

I'm thinking of going this weekend to. 

 
Air450 said:
You still have 3 tubes connecting it together! Drive it like you stole it and fix it when you get back home! :lol:  

Been there done that. Had Dario make me some new ones with solid gusseting and the next thicker tubing. No more cracks on my car.

They always crack where those curved gussets end. 

I'm thinking of going this weekend to. 
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Hit me up Carl. I'll be there tomorrow till Saturday afternoon 

 
Tatum Sand Demon said:
Parshall gusset created a stress riser area at the end of the weld. Even if the welds were past the gusset and crow footed out most likely would have happened.  Weld past  gusset and blend in w/ grinder flapper wheel to nothing.
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Agree.  Possibility for similar failure on the upper tube as well.

Also, had me wondering what a "Parshall gusset" was for a bit. :biggrin:

 
Weeeeellllllll, you got 2 choices, which you knew.  Fix it, or not.

ON the fix-it side, you can:

Buy a new one

Buy the one from LRS and change the tabs or whatever you need to fit your build

Fix yours....I had no idea what a Parshall gusset was.  But, It don't take an engineer to see why it cracked there (you have two pieces that are "Beefed-Up" and a short gap in between where are the stress is gonna be shifted to/concentrated. 

Add the choices up and pick the cheapest/fastest way out (assuming that strength is the same)

 
A bit off topic but - What is the nut welded into the outer arm gusset used for?

 
You could also get a trip out of it by not welding it. (This allows it to flex).   But, weld strips of strap on top of it.  I forget on where that should be welded....I don't think that it is all the way around.  Stagger the strap.  Then weld what you can't see. 

You could do that in an hour and get a trip out of it...no running, jumping, pushing, shoving....EASY driving (yes, there is such a thing).

Then, change it out when you aren't rushed.

 
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