mancini tube upper control arm failure....

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Sure, tubular A-arms can be VERY strong. But I'm just guessing here, it looks like the tubing diameter and overall design of those arms is VERY different. Just because the a-arms on the buggy will do that doesn't mean the ones on your mopar will. Apples to Oranges on that one.
 
Did anyone wonder if maybe the wheel made contact with the curb then the whole front end corner with a tree before the tube broke.....not calling anyone a liar but damn, that front end took a vicious hit....look at how bad the wheel is bent and look at the damage to the corner of the radiator support and front frame member.

Could something else have happened before to cause the accident that may have caused the weld to break? Like a blowout?........just another way to look at it.

I mean I bet the whole accident took about 5 seconds so what happened first? Chicken or egg?
 
I also wonder because I have an RMS system on my car and I have 0 miles on it:read2:.....homework time....I would shizzle if something like that happened.
 
From what I see here if I ever buy any fabricated parts I will use X-ray as my preferred method of NDT
 
momoparman said:
Did anyone wonder if maybe the wheel made contact with the curb then the whole front end corner with a tree before the tube broke.....
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The TUBE did not break, the weld did. I've been a union pipefitter for 8 years now - I've been to buildings that collapsed ( tropicana casino @2006) and piping was demolished - the welds did not break, and the piping was bent like pretzels - from 24" piping to 3/4" piping - so the fact that the arm is not twisted like the sheetmetal and the weld was the weakest link is cause for concern. I dont have an engineering background but real world experience has shown me that welds should not fail like that - the piping should bend ALOT before a crack even shows, and IF there is a crack that is a sign of porosity, or many other variables in a bad weld.
 
momoparman said:
I also wonder because I have an RMS system on my car and I have 0 miles on it:read2:.....homework time....I would shizzle if something like that happened.
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There are RMS systems with over 60,000 street miles on them. 9 second quarter mile cars and road course kinda cars with them. I bet if there were probs they would have surfaced by now.

I am not convinced by a fuzzy pic that the cap arm caused the crash. Maybe the Bigblock, 3800lb car w/ skinnies on the front, drum brakes, steering components, the drivers foot or overcorrecting, curb, etc....may have something to do with it.
 
momoparman said:
Did anyone wonder if maybe the wheel made contact with the curb then the whole front end corner with a tree before the tube broke.....not calling anyone a liar but damn, that front end took a vicious hit....look at how bad the wheel is bent and look at the damage to the corner of the radiator support and front frame member.

Could something else have happened before to cause the accident that may have caused the weld to break? Like a blowout?........just another way to look at it.

I mean I bet the whole accident took about 5 seconds so what happened first? Chicken or egg?
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An even better point! I think we all assumed the A-arm broke first, but based on the info we have we really don't know. Further, on re-reading the info, he said BOTH UCA's broke.

No way, no how do both UCA's break at the same welds at the same time just driving down the street. If both arms truly broke at the welds, that damage was caused when that thing pounded the curb at 45mph. Try that with your stock components and see if they hold up.

It does point to the weld being the weakest link. But for a A-arm to hold a ball joint like the Mopar's you end up with a thin wall tube welded to a thicker ball joint socket. Given the short section of tubing, its not surprising to me for the weld to be the weak link. Typically in engineering applications welds are evaluated at 80-90% of the strength of the materials used. In an application with a longer tube, it would make sense for the tube to bend first. But with a short section of tube, and a very short, sharp impulse, (pounding into a cement curb) the joints take the hardest hit because they take the force basically in shear. The rims hit the curb and they stopped. The car kept going, maxing out the suspension. With the wheel and the spindle stopped, the A-arms hit max travel and stop, and then all the force goes to the a-arms and the a-arm mounts, something has to give. Its too bad we can't see the A-arm mounts on the frame.

At this point, I'm not sure any of us can make any claims. Its pretty obvious we don't have enough details to figure out what happened first. We're all jumping to conclusions based on a few fuzzy pictures and a very short description of events.
 
momoparman said:
Did anyone wonder if maybe the wheel made contact with the curb then the whole front end corner with a tree before the tube broke.....not calling anyone a liar but damn, that front end took a vicious hit....look at how bad the wheel is bent and look at the damage to the corner of the radiator support and front frame member.

Could something else have happened before to cause the accident that may have caused the weld to break? Like a blowout?........just another way to look at it.

I mean I bet the whole accident took about 5 seconds so what happened first? Chicken or egg?
Click to expand...

momoparman said:
I also wonder because I have an RMS system on my car and I have 0 miles on it:read2:.....homework time....I would shizzle if something like that happened.
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i've seen an alter-k that has hit a curb. a few years ago at carlisle a guy brought one back to bill. apparently the guy got cut off and slammed into like an 8" curb. he was picking up a new alter-k at carlisle that year and bill wanted to see the smashed one so he could see how it took the hit and if there was anyway to improve on it. i can say the thing was bent all to hell but there were NO broken welds. i don't care what happened to the black runner in the pics. the welds should not have broken. the welds are suposed to be the strong spot. look at the arm in the pic. it isn't even bent,( just tweaked a tiny bit).. just broken at the weld.
 
momoparman said:
I also wonder because I have an RMS system on my car and I have 0 miles on it:read2:.....homework time....I would shizzle if something like that happened.
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two totally different companies. no need to wory about the RMS stuff. thats top quality stuff.
 
Yes I can tell the weld is broken...and yes...I looked at that C_AP stuff and it looks thin and weak just sitting there...nothing like the RMS arms. I see the weld broke but like the other comments made, that short arm would probably stay straight and if it got hit on the shear plane then the weld would have broke on impact.....bad weld or bad mistake.....who's to say now.....I just have a hard time believing that a break like that occurs just driving down the street. Look at the whole damaged area around the wheel.....there is a lot more going on there that the pictures arent showing.

Mop.
 
Man, that sucks. At least it didn't happen while he was going through the traps at 100+.
 
There's one thing everyone needs to realize...in the Mopar SLA front suspension, the upper control arm has very little load to support, especially in comparison to the lower control arms. If you look at vehicles with similar suspensions (torsion bar 4x4 trucks are a good example), you'll find the upper control arm is very small, and many times made of aluminum anymore. The lower is much beefier.

This is an upper control arm for a Hummer H3, which comes stock with 285 width 33" tall tires.
129_0903_10_z+hummer_h3_suspension+domed_feet_shock_cylinder.jpg


C4 Corvette (3000lbs and factory fitted with 275 width rubber)
DSC_7267_a.jpg


On the stock ones...I've had the ball joint threads fail and the ball joint back out of the arm...does not cause an accident, and a cracked bushing hole I have seen as well. It happened when i removed the OEM bushing. The bushing hole crack would take a very long time to fatigue to failure if it ever did. Put one of the stock steel ones through an accident and it will bend like a taco, but it likely won't come apart.

The welds should NOT be breaking ever.
 
72bluNblu said:
Sure, tubular A-arms can be VERY strong. But I'm just guessing here, it looks like the tubing diameter and overall design of those arms is VERY different. Just because the a-arms on the buggy will do that doesn't mean the ones on your mopar will. Apples to Oranges on that one.
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Ya the tubing is stronger and the design is very different. BUT! it is still welded together. My point was good welds should not brake.
 
Last time I saw a loss-of-control like that from driving on the street it was from a broken torsion bar. How are the T-bars on that car?

It also is pretty stupid to run a big block blown(?) car with drum brakes.

Who spends money on tube uppers but runs the stock brakes? What the heck is that about?

All that said, the weld should not have broken.

Steve
 
Wow! I stumbled on this site while shopping for control arms for my Dart, good thing too. Judging by the picture on the CAP website, I was shocked at how sloppy the welds looked on their lowers. Giving CAP the benefit of the doubt concerning their welds (not seeing it in person), there is simply not enough material at the ball joint socket. A gusset is needed like on some of the magnum force versions for safety. Still though...did the arm cause the accident or did the accident break the poorly designed arm?
 
I have to disagree. IMO, having a gusset there would help limit the torsional stresses at the joint cup even if the weld was properly done. For others like me that are shopping for arms, IMO, should think twice about that design. The owner is lucky, it could have been a lot worse. I hope that that car get on the road soon. Cheers!
 
Skywarp11 said:
I have to disagree. IMO, having a gusset there would help limit the torsional stresses at the joint cup even if the weld was properly done. For others like me that are shopping for arms, IMO, should think twice about that design. The owner is lucky, it could have been a lot worse. I hope that that car get on the road soon. Cheers!
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I disagree. Look at the arm. Barley bent at all. That should be bent to he'll before it should break. And on top of that the metal on either side of that weld should have broken before the weld. There is no need for a gusset if the proper material is used and the weld is good. Even if that arm had a gusset it may have taken a little longer to break but it was still breaking
 
I have CAP ucls on my Barracuda, I'm not sure what caused the weld failure but the 3rd pic down shows the front tube of the control arm pushed back. The forces working on that ucl are more front to back..it locates the upper ball joint. All the major force is on the lower ball joints (I've never lost the upper ball joints but have lost the lowers). I would love to see the lower control arm. But I do agree the weld should have held..I'll be watching mine and maybe have a gusset plate TIG welded in.
 
for those of you looking for upper A arms look at firm feel,,nice piece they will be my next upper A arms
 
momoparman said:
Yes I can tell the weld is broken...and yes...I looked at that C_AP stuff and it looks thin and weak just sitting there...nothing like the RMS arms. I see the weld broke but like the other comments made, that short arm would probably stay straight and if it got hit on the shear plane then the weld would have broke on impact.....bad weld or bad mistake.....who's to say now.....I just have a hard time believing that a break like that occurs just driving down the street. Look at the whole damaged area around the wheel.....there is a lot more going on there that the pictures arent showing.

Mop.
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On Moparts Abodyjoe posted these pictures and people knew the car that was in this accident. They were locals that have see the car around all the time.

They said the owner is very hard on the street with this car. They see him sideways quite often.
 
autoxcuda said:
On Moparts Abodyjoe posted these pictures and people knew the car that was in this accident. They were locals that have see the car around all the time.

They said the owner is very hard on the street with this car. They see him sideways quite often.
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Still wouldn't break the weld. The other thing is if I remember correctly the car is from Detroit. The arms were bought in dec of 08. They broke in may of 09. How much use have they really gotten in that short period of time? I know that in jersery the weather didn't allow all that much use. And I believe that Detroit has a little longer and colder winter.
 
autoxcuda said:
On Moparts Abodyjoe posted these pictures and people knew the car that was in this accident. They were locals that have see the car around all the time.

They said the owner is very hard on the street with this car. They see him sideways quite often.
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Ya so what? Welds still should not have broke like that.
 
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