Broken Control arms

[jdeft1]

Been crashed?? Looks like it..

[Tom, F&L GoR]

Something is fishy. If the sway bar end link bracket broke off - and it is the front bar since there is a radiator hose and steering rack in the pix - then the car would be downright scary and dangerous to drive. The rear roll stiffness could cause tremendous oversteer without a front bar to balance it. And the owner only realized something was wrong when backing out of the driveway? More details, more details!!

[Tom, F&L GoR]

This isn't Nadine's after hitting the curb during the run through the streets, is it?

[HISSSN1]

This Viper Needs A Complete Safety Inspection.

[GTS Bruce]

If the rest of the car looks that bad maybe its time for RIP. GTS Bruce

[ViperGTS]

If you hit it hard enough a control arm might break, yes...

[GTS Dean]

That car hung a major pothole or curb. It looks like a pure tension failure to me. With the amount of corrosion evident, it makes you wonder though.

[Tom and Vipers]

A sad little "secret" about aluminum is that it has NO ENDURANCE LIMIT.

In other words, it has no Endurance Strength, which is the maximum stress level that can be tolerated while still exhibiting infinite cycle life.

In other words, given enough cycles, aluminum will fail at any stress level no matter how small.

There are 2 recent exceptions to this characteristic: Cast 319 (a modern block alloy) and Hypereutectic (as used in pistons.)

It is possible Cast 319 was used.
____________________________

To make matters worse, I don't care what the stress analyst said, those sections look too thin.

[2000_Black_RT10]

Originally Posted by Tom and Vipers

A sad little "secret" about aluminum is that it has NO ENDURANCE LIMIT.

In other words, it has no Endurance Strength, which is the maximum stress level that can be tolerated while still exhibiting infinite cycle life.

In other words, given enough cycles, aluminum will fail at any stress level no matter how small.

There are 2 recent exceptions to this characteristic: Cast 319 (a modern block alloy) and Hypereutectic (as used in pistons.)

It is possible Cast 319 was used.
____________________________

To make matters worse, I don't care what the stress analyst said, those sections look too thin.

It reads as if you are referring to fatigue. The words such as endurance strength are uncommon.

For anyone new to this.. Stress is a measure of how material can fail under high compression or tension. Strain is stretch, measured inch per inch or mm per mm, etc.. basically how much can the material stretch before failing. Fatigue is a cycle of stress and / or strain.

Hypereutectic contains silicon, upwards of 19% content.

The deceiving part of an alloy (which is mix of material) is that you will get different results, either in stress or strain. There are many, many mixes of material in castings and forgings which should not be referred to as simply aluminum. Some examples of mechanical properties of cast aluminum alloys inc. 319 are..


Please don't take any offense to this next comment.. As you mentioned "I don't care what the stress analyst said, those sections look too thin", this can be extremely challenging. Many times in my career it was thought to beef up a part, increase material thickness, yet this caused too much stiffness and transferred the stress into another part of the component / part. It is very tricky and it is an ignorant statement to simply say that you don't care what an analyst says. In the world of engineering and design, modelling a component is extremely complex.

Best regards,
Mike

[99 R/T 10]

Originally Posted by 2000_Black_RT10

Please don't take any offense to this next comment.. As you mentioned "I don't care what the stress analyst said, those sections look too thin", this can be extremely challenging. Many times in my career it was thought to beef up a part, increase material thickness, yet this caused too much stiffness and transferred the stress into another part of the component / part. It is very tricky and it is an ignorant statement to simply say that you don't care what an analyst says. In the world of engineering and design, modelling a component is extremely complex.

Best regards,
Mike

While this amy be true and the engineers are suppose to be the smart people on the subject, they have also made mistakes. I am in the camp of always "over build" when possible. The engineers have to take into the cost factor and may/do just build to the minimum cost level that computer design says is safe. I think a safe bet for right now is to have a some spare control arms around, just incase if you have a lot of miles on your car.

Not so important for the garage queens

[2000_Black_RT10]

Mistakes happen.. oh I'm not a smart engineer either.. just babble too much.. you should see the past Mustang lower control arm recall.. they replaced all of them with billet arms. Small cost saving could turn into a huge cost penalty in a higher volume car. Low volume cars can be victims of reduced testing in some cases having less of an engineering budget. A steel lower control arm would be the ideal solution for strength, unfortunately it negates reduced weight performance, unsprung and total vehicle weight.. Computer simulation is only good for establishing the initial design direction, not for final validation, far too many variables in this example, even corrosion needs to be accounted for. I have no idea how the control arm was designed and tested and am in no position to defend, it's all just babbling bs'g from my end.. I enjoy the discussion.
Mike

[Tom and Vipers]

Any aerospace stress engineer would look at that control arm at the bushing and yawn.


Yawn....


I'm sleepy.....

[plumcrazy]

my 98 front passenger side just broke last night. 50k miles

THANK GOD i was in traffic and was braking. only broke at about 20 mph. no other damage

[Martin2000GTS]

hey plum crazy did you see my post on my 2000 gts that broke a month or so ago, i was going abou t 20 mph and just came to a stop right in front of my drive way and my lower right cracked right at the connection to the frame, this is weird that a few are haveing this problem. I bought a replacement from viper parts Larry....i think that was the name, John B has them to for like less than half the price of a new one from dodge which is like $790. My Dad and I replaced mine in my drive way in a Saturday and were avg do it yourselfers, actually looking at the type of car you have you can probably do this job in an hour lol ! good luck

[plumcrazy]

i remember reading it but couldnt find the thread. i wanted to post in that one too for a heads up for guys.

im gonna replace them all. not so sure about new or used yet. or if there is an upgrade.

it scared me cause EVERY single day i drive it, my goal is 150 minimum and i rarely ever miss......