Front Lower A Arm just snaped how does that happen?

[Martin2000GTS]

Yeah I bought it with 4,000 miles on it. This is the 1st problem I have ever had with it. Had it for a tad over 4 years now. Ill get those pics im leavin work now.

[dave6666]

Originally Posted by Martin2000GTS

This is the 1st problem I have ever had with it.

Shortly after I got my GTS I discovered it really drinks the gas. And I thought my 1st problem sucked!

[Martin2000GTS]

haha thanks Dave! Hey Mike I sent you those pics.

[99 R/T 10]

Got'em. Here are the pictures. I hope this isn't a trend;

[Tom, F&L GoR]

Is the inside of the a-arm hole the bushing presses into smeared (can't tell from pix.) The bushing is pressed in and should not rotate inside the arm.

[dave6666]

Originally Posted by Tom, F&L GoR

Is the inside of the a-arm hole the bushing presses into smeared (can't tell from pix.) The bushing is pressed in and should not rotate inside the arm.

Rubbing...? Friction...? Heat...? Failure...?

Hard to tell in those pics. And all in all, those parts look pretty good.

Was trying to see in that second pic if you could see impact damage to the pivots or frame. Looks clean in my eyes.

Any scars or scrapes on the bottom of that a-arm that might be a clue?

[Tom, F&L GoR]

The bushing should not rotate inside the a-arm hole. If it looks smeared, then perhaps the bushing was too small or hole too large...

[dave6666]

Originally Posted by Tom, F&L GoR

The bushing should not rotate inside the a-arm hole. If it looks smeared, then perhaps the bushing was too small or hole too large...

What is the method of failure you are suggesting relating to the problem you keep suggesting? I mean, at least I got it - and agree - that the bushing should not rotate in the arm, but how would that cause failure if it did? You have now brought it up twice. And no comment to me noticing you brought it up after the first time.

[Tom, F&L GoR]

Dave, I read your comment asking about scars or scrapes as if you did not think it had rotated. Without voice inflection, I guess I didn't get it and interpreted your reply differently - apologies. And hey, we're quizzing the owner who can actually look at it, not each other.

The bushing has to be tight at the center since the alignment bolt bottoms on the center tube. If the bushing was loose in the arm, it should smear the inside. Also, I would like a description of the metal surface where it came apart. The photos show the left break as darker, indicating it may have cracked some time ago. If so, it may also appear slightly smoother. The right side looks cleaner and brighter - or fresh. (This may all be the flash or the lighting, though.) If that's the case then the failure began some time ago. Perhaps more history of the car would help figure it out.

Regardless of the bushing, it is an interesting failure of the arm. If the bushing were tight it would twist the rubber like it is supposed to. If it were loose it would show distress and perhaps have squealed. I think if it were loose,it would have worn evenly all around the hole and should still not break.

Is there any reason to believe the bushing was installed crooked? Maybe that started a crack and time caught up to you.

Any signs of interference of the arm and the frame (prior to failure?)

[2000_Black_RT10]

The fracture direction indicates fore - aft stress, I don't see how an axial load on the inside bushing diameter would cause failure, it's on a bushing that can provide flexability at the joint. If it was a hard joint.. sure..

First thing I would do is evaluate what changed in the design. I'd typically rule out fatigue if it wasn't tracked, etc.., most probable cause then would be a collision of some nature.. even then, most OEM designs can accomodate a good hit before fracturing.

What changed? The car is sitting lower, are these stock shocks with a new set of eibach springs or aftermarket shocks? What is the spring rate of the new springs? I assume they are a bit stiffer accomodating less wheel travel, and this would also reduce rotation at the joint, in conjuntion with your points Tom. I also wonder if the shocks can accomodate the stock bump limit, limiting jounce. Some just go ahead and swap shocks and springs, not aware of retaining the correct bump heights. JonB had a good point about bump steer, just wondering if toe was adjusted after dropping the car, there should be some tire wear to indicate that, and stickier tires can toss in a bit more stress as the joint. I think it is a combination of factors, and a good pothole hit one day, bottomed out the shock and broke the camels back, and as Tom pointed out, it looks like one fracture has been around for some time, and your revived braking power finished job.

[Tom, F&L GoR]

If it was due to impact, would not the mounting bracket also show distortion? That probably depends on the relative stiffness of the arm and of the bracket.

I had put the shock/spring idea in the backseat because too many other people (including myself) have changed them and we haven't seen a flood of broken arms. On my Gen 1 I think there are rubber jounce stops to prevent excessive arm movement rather than allowing the shock to limit travel. Probably something similar on Gen2?

Not saying this is it, just that this is my train of thought and what I think is more likely and less likely. Based on all the chit-chat here, the Viper overall has been fairly robust, so I'm still guessing it was a small mistake early on (bushing install issue?) that caused a small crack, leading to a big crack.

[dave6666]

I might be inclined to go with the misaligned at the onset business. It does not take much with a press fit tolerance to cause problems when going in crooked. Especially steel into cast aluminum.

Kind of alarming if the case though. Makes me want to dye check mine. I mean, these things don't always break conveniently 10 feet from your driveway at 7 mph.

[Catwood]

Is it possible that someone jacked up the car using the a-arm as the jack point?

10 feet at 7MPH?.....let's worry about 125 at 1.6G going turn 8 at willow. That will make you pucker

[dave6666]

Originally Posted by Catwood

Is it possible that someone jacked up the car using the a-arm as the jack point?

10 feet at 7MPH?.....let's worry about 125 at 1.6G going turn 8 at willow. That will make you pucker

For one, the car is held up by the a-arm. I can't imagine that causing harm by jacking the car that way. There should be tell-tale scars if so under the arm left by the jack.

125 at 1.6G??? That was my point...

[2000_Black_RT10]

No debate here Tom, just sharing an opinion.. it's funny when people lean towards a probable cause without actually determining the initial point of failure and why I'm limited to a guess looking at jpegs.. I'd be a fool to do that.. and I understand your requests for more info!!

This image posted illustrates quite a bit of uneven bushing deformation, it appears something was binding or misaligned, yet these bushings can accomodate misalignment for camber / castor adjustments.. I just don't think pressing in a mild steel tube into a high quality cast aluminum arm will cause an issue, even with misalignment initially, the length of the tube will straighten it out. Sure if it was a solid piece of steel being pressed in, but not a tube.. the tube would kink before going in any further.. the steel tube is much weaker then the aluminum arm..



Catwood may be right, maybe just some external damage to the aluminum, I still suspect some added joint stress being stubborn with bench opinions.. Knowing the design of the arm.. they insert a steel rod in the length of the arm during the casting process, so the arm itself is very stiff, and if it's going to break under impact.. it'll most likely happen at one of the joints. Not sure.. definitely puzzling.. I understand your comment about the bracket, yet it's almost a boxed section, and I wouldn't rule out a casting issue, porosity or ? something, who knows.. until someone can actually look at the physical parts and the actual suspension geometry...