Broken Control arms

[eucharistos]

my goal is 150 minimum and i rarely ever miss

niiiiiice!!!!!

BTW, how did you know it broke? Sound, wobble, tracking. Can they be broken (cracked) for a while before symptoms show up?

Thanks

 

[plumcrazy]

when i was braking harder, i heard a POP, a bang, instantly saw tire smoke, some wobble but i wasnt going fast at that point and heard the tire hitting something. luckily i was driving in 55mph traffic at that point and was already braking.

 

[VIPER BAZ UK]

These things are getting to common now and all seem to be 1999/2000 vipers.....

Glad your OK Phill good job this happened at this speed and not what that BEAST is capable of..

 

[Zrxpilot]

Found a cracked one on my drivers side rear upper. The foward leg of the A. My car had been in a wreck several years ago and presumably happened then. The material seems to be a bit more porous than I would expect in a location such as this but *** do I know. Looks like an easy fix. 97 Gts.

If anybody has a used one, let me know.

 

[Kevan]

Wow. I'm going to join the geek fray, if I may.

In layman's terms, the difference between cast aluminum and billet aluminum is the difference between Ernest Borgnine knocking on your door, and Jenna Jameson knocking on your door; sure, Ernie was cool in 'Escape from New York' and 'Airwolf', but Jenna would be much more fun to hang out with the day after the hot tub got installed.

I'm not up-to-date on when COSMOS testing became prevalent in the auto industry, but I know it's been around for a while. I would HOPE that DCX would run those kinds of tests on (at least) specific parts, like the suspension components.

I think what folks would like to see is COSMOS testing (animated computer stress/force testing) on the A-arms. I'd be happy to do that, but I don't have a spare A-arm laying around to spec, nor do I know the exact alloy they use on those arms.

If the cast A-arms are $800 from Dodge, plan on over $3K for billet ones.

An option that I did not see mentioned, that might be something for Dodge to think about in the future, is what's called Metal Injection Mold (M.I.M.). We use this process on one of the parts to my first invention, and it's worked out VERY well. MIM is much like injection molded plastic, but they use metal instead. It's under VERY high pressure when injected, so there's less air and fewer voids. This means you get a stronger part. Now, it's not as strong as machined, but it's WAY stronger than regular casting.

The initial cost of the MIM mold it kinda pricey (probably high 5-figures), but so is the mold if you're going to straight cast it.
With the right production numbers, the costs can be "reasonable" to both DCX and the consumer, but strength and durability would be increased extensively.

Food for thought.

(BTW- the upper A-arms on the SRT-10 trucks damn thin as well)

 

[99 R/T 10]

So If I see this correctly, it seems to be the lowers that are failing(mostly fronts), correct? Kevan,
I can send you a couple(front and rear lower) to test out if I can get assurances that I would get them back. PM me.

 

[Kevan]

PREFACE: I AM NOT A PROFESSIONAL ENGINEER.
I have 2 degrees, but neither is in engineering. I pull from my 15 years experience in the film equipment industry, and my last few years as an inventor.

Just wanted everyone to know that before I get any nasty-grams.
----------------------------------------------

So If I see this correctly, it seems to be the lowers that are failing(mostly fronts), correct? Kevan,
I can send you a couple(front and rear lower) to test out if I can get assurances that I would get them back. PM me.

Thanks.
I think there are a few members here that can vouch for me (or drive to my house and 're-acquire' them...heh heh).

The only thing left would be to find out what, exactly, Dodge is using for material.
That's the difficult part.

I'd like to get with a couple of the other guys in this thread (namely Tom F&L GoL, Tom and Vipers, and 2000 Black RT10) and discuss this subject.
These guys *are* professionals and know what the F they're talking about.
Just to sit in on the conversation would be a fantastic learning experience for me.
---------------------------------

QUESTION 1: Are the control arms the same for the Comp Coupes?
QUESTION 2: No one produces (cast or machined (or MIM)) replacement control arms?

 

[Tom F&L GoR]

Mechanical engineer, yes. Jack of all trades, master at none is the joke.

I think looking at the broken arms is the start. They obviously are of the suspect material, and someone (not me) familiar with failure analysis should be able to determine to mode of failure.

Mike (2000 Black RT10) has one broken one and starting something, so let's let him finish or say if he's exhausted his sources. Then it would be helpful for a Chrysler employee to reveal the material and manufacturing method. Hopefully Mike's analysis is even a possiblilty with the given material description and we can go from there.

As a Gen 1 guy, I'm still interested for personal reasons. I bought an aluminum front suspension in pieces and parts from eBay and wherever to lighten up my car someday. Who knows what year parts I have....

 

[99 R/T 10]

Well, an endorsement from Tom is good enough for me. Kevan, if you can PM me your address, I will ship out the front and rear to you tomorrow.

 

[Kevan]

Mike (2000 Black RT10) has one broken one and starting something, so let's let him finish or say if he's exhausted his sources. Then it would be helpful for a Chrysler employee to reveal the material and manufacturing method. Hopefully Mike's analysis is even a possiblilty with the given material description and we can go from there.

Well, an endorsement from Tom is good enough for me. Kevan, if you can PM me your address, I will ship out the front and rear to you tomorrow.

I agree with Tom on letting Mike finish his sorcery (heh heh), and then we can go from there.

If you still want to send me the control arms, I can at least get them into the computer and start trying to break them in there. It might be a good thing to have 2 different people working on it...a little variety maybe.

I am NOT a COSMOS testing expert by any means, but I have resources and time....and that makes me pretty damn dangerous. LOL

I'd like to help out on the project if I may.

 

[99 R/T 10]

I'll let you guys figure out where you want me to send them, just let me know too

 

[plumcrazy]

mine should be off the car next week at some point. i can send a used UNbroken front passenger side and a broken front drivers side out if anyone can help figure this out

both lowers

 

[99 R/T 10]

Hey Phil,
Check the part numbers on both sides. I can't remember if was the front or rears, but I think they are the same #. One part will fit both sides.

 

[plumcrazy]

tator is sending me the new ones....i trust him.

 

[Kevan]

Well, I just saw the OTHER (older) thread about the broken control arms:
http://forums.viperclub.org/rt-10-g...nt-lower-arm-just-snaped-how-does-happen.html
Looks like you guys are way ahead of me.
Mike has animation completed on one section, and computer analysis almost matches the actual failure lines. Pretty impressive!

I think I'll play the part of Matt Cassel on this project.
If you run into a Bernard Pollard problem, let me know.

 

[dave6666]

I'm going to dye crack check all of mine this week or so on my '01. We'll post pics of how it all works out.

 

[2000_Black_RT10]

Mechanical engineer, yes. Jack of all trades, master at none is the joke.

I think looking at the broken arms is the start. They obviously are of the suspect material, and someone (not me) familiar with failure analysis should be able to determine to mode of failure.

Mike (2000 Black RT10) has one broken one and starting something, so let's let him finish or say if he's exhausted his sources. Then it would be helpful for a Chrysler employee to reveal the material and manufacturing method. Hopefully Mike's analysis is even a possiblilty with the given material description and we can go from there.

As a Gen 1 guy, I'm still interested for personal reasons. I bought an aluminum front suspension in pieces and parts from eBay and wherever to lighten up my car someday. Who knows what year parts I have....

Thanks Tom. As some may know I work at a top suspension company, from OEM to F1. It's the type of company which the OEMs and many race teams (Daytona, F1, Le Mans, etc..) come to for suspension advice, design & manufacturing.

The control arm that I received from Martin failed due to an impact. There is no sign of porosity issues, carbon deposits (from casting), or signs of a duration of fatigue / strain or stretch indication in the material. Our test manager reviewed the control arm, and that was his feedback.

Typically cast a-arms rely on the quality process of casting, the most common failure is due to the casting process, impurities, etc.. Yet this is not the case with Martin' control arm. It was clearly a hard hit that initially fractured the arm.
Mike

 

[LiquoRT/10]

When you say a hard hit is what caused the break are you saying a hard hit on the arm itself ? Wouldn't there be a mark on the
arm where it hit ? Or do you mean a hard pothole hit causing a fracture in the arm and eventually breaking ?
If we go with the pothole theory wouldn't the rim be damaged also ?
Can you (or did you) figure out at what angle the arm had to be hit to create a break in that location ?

 

[plumcrazy]

yeah please clarify in english for ME...lol

i'll send you mine if you want it to look at as well, later this week maybe

 

[dave6666]

The control arm that I received from Martin failed due to an impact. There is no sign of porosity issues, carbon deposits (from casting), or signs of a duration of fatigue / strain or stretch indication in the material. Our test manager reviewed the control arm, and that was his feedback.

So for those with Gen 2 cars (like me) is it your recommendation that if we are positive the vehicle has never had a side impact contact that we should be warm and fuzzy that we are safe? It seems the ones that have happened so far have luckily happened at low non-aggressive speeds/driving styles. What if one of these went while having "fun?"

Also, are you going to look at Plum's broken arm to see if it fits the profile of having been impacted?

I know my first statement/question above is a little tricky, and from a liability standpoint you'd be best off not to answer it. I poised it that the way I did to maybe let everyone think a few thoughts about their own cars. I mean, how often do we get in our rides and wonder if the suspension is going to fly apart at speed due to something that happened way back? That we may or may not even have been aware of?

I certainly appreciate the work you did with that broken arm. I am a little more warmer and fuzzier than I was before, but as my car has had multiple owners, let alone my run-in with those lane divider bumps last week , I'm still going to do the penetrant dye check before I get back on the road. And the update on that for anyone that had been interested is, great weather here, working on construction projects outside. Car is napping in the snake den for now.

 

[2000_Black_RT10]

When you say a hard hit is what caused the break are you saying a hard hit on the arm itself ? Wouldn't there be a mark on the
arm where it hit ? Or do you mean a hard pothole hit causing a fracture in the arm and eventually breaking ?
If we go with the pothole theory wouldn't the rim be damaged also ?
Can you (or did you) figure out at what angle the arm had to be hit to create a break in that location ?

It can be determined how the aluminum fractured, quickly or due to fatigue, in others words - a slow stretch like bending a piece of metal back and forth or an abrupt crack that occured under force. It can be viewed under a microscope, effects of fatigue result in ripple type of lines in the material due to elongation due to repeated strain, in other words - the material is stretching and relaxing, stretching and relaxing.. this affects the material physically. This arm had no signs of strain, it was cracked with a one time hit, most likely a curb or something hit, not a hit on the arm itself. Since it was a one time hit that caused the fracture, next would be to review the material, looking for any defects in the material. During casting there can be carbon deposits or voids which can cause a weaker casting, there were no signs of either in the material at the fracture.

This fracture on Martin's control arm ocurred on the forward lower bushing, the most common place for an arm to break. The ultimate test for control arm strength is simulating a curb hit with the brakes on, and this is where a cast aluminum control arm would fail, typically.. It would be interesting to know the past life of the car, Martin didn't own the car since day one, who knows.. anything is possible.. The unusual part of Martin's control arm is that the sway bar mounting tab is also cracked, odd because of the fracture and that the tab is connected to a link, not a rigid component.

I'm going to get some pics, just been meaning to get a new camera, on my last trip to the UK it got damaged in my suitcase! Neil from the UK even saw my camera. I've also been meaning to put a load on the control arm to see how much force it can take, and slacking with other stuff.. It's just been nuts at work.. extremely hectic.. Plum if you want to send your part, I'll PM you an address.
Mike

Edit.. was a simultaneous reply above with Dave & hi, I know a bit about the past Mustang control arm situation from others in the industry.. this was a situation in which the cast control arm resulted in a huge recall, Ford had to replace all arms with billet arms. Surely there can be a liability, it's pretty scary for manufacturers if a part fails and it's their fault, pretty much the reason why they spend more time on testing and validation than the design process, compiling records, sign off from the OEM, and who are regulated by goverment approved test procedures , SAE, etc.. It can be overwhelming for designing street cars, so much testing. It's a reason that I typically do not like aftermarket components in a general sense, some are good though, but the majority do not pass all the requirements for street duty (lots of miles, environment hazards, salt, etc..), they don't have to do this testing (for obvious reasons.. it costs money and time), all they do is add some fine print, this part is for "off road use only". That wipes away their liability concerns.. If you drive your Viper off road on a course, you have absolutely no defense if your car beaks in a liable situation with the OEM if something were to happen. If an incident occured on the street, that's another case, but if the car was driven on the track at one time, it will be very tough to fight that battle.. I caught your Post and the rim damage, that sucked, I would be extremely annoyed myself and be on a mission for them to pay for the damage. I sent a PM to Plumcrazy. Cool idea to dye check your arms, look forward to the pics. All of this concerns me a bit, these cars can endure a nasty life of abuse, one little fracture can cause an injury or death, Martin is very lucky that his arm did not finally fall apart when driving at high speed, opposing traffic, etc.. Not to sound like chicken little.. but I would definitely encourage anyone to check their arms, especially if you're not aware of the car's past life.
Mike