Broken LCA on 2012 Chevy Volt

[Hokiefyd]

Originally Posted By: meep
what I can't get is how the arm finally let go on its own while the car was unoccupied. did it start as she was parking as a crack, then finish itself off while the car was sitting still? Was it cracked and then let go when she shifted into gear? did someone tag the tire or wheel while she was parked with a direct blow? was the bumper bumped hard enough while parked that it jolted the crack that was already started?


I bet it happened WHEN she parked (stopped). There was likely already a crack in the arm and during the what I presume was a typical turn-in-and-stop parking situation, there can be a good bit of torque on suspension components. Given the description, I'd say that it's like that the arm broke AS she parked/stopped. At that point, only the most observant driver would likely recognize it...since the car was nearly stopped or in the action of actually stopping already anyway.

Then, when they get into the car, engage the transmission, and release the brake, especially if there was any turning of the wheel while stopped to pull out, the wheel could have assumed any actual angle of motion.

I don't find the story hard to believe at all. I would report this to the NHTSA. If her vehicle is the only report of it, then it's possible that it was a casting fluke in that arm. But if there's a trend of this, there could be a larger issue looming.

It wouldn't be the first time a line of vehicles has had control arm problems, though I'd admit that most in the past have been corrosion related...probably something relatively foreign to a resident of Hollister, CA.

 

[wrcsixeight]

Anybody else see what appears to be rather extreme inner tire wear?

I guess it could just be the scuffing from after the fact, but if this tire is worn that much on the inside edge, this suspension had issues going back to long before this concrete post attacked your wife's honor, and filled your kids bellies with icecream.

Having grown up with a 70's style feminist mother, and an older sister, I can assure you that no woman, since the beginning of time, has ever done anything wrong, ever, and no matter what, this is simply your fault, and the fault of all men, everywhere, because we are all just buffoons worthy of the derision we so readily invite.

 

[Trav]

When my MIL took Toyota Corolla 4 wheeling and finally hit a set of 5 concrete steps on a house with the L/front it did a lot of damage.

Bent the wheel, bent the subframe, wiped the bumper and radiator support, wiped the fender and bumper out but the control arm still looked okay.
Of course i replaced it with new ball joints and tie rods, the point is the wheel doesn't seem damaged, no impact marks on the control arm either.

If the LCA is that weak to break in half with that little impact (if in fact it was broken due to impact) then IMHO its still a real safety issue.
The LCA could have been holding together by a thread and unloading and loading the suspension just getting in and out could have finished it, who knows.

It shouldn't have with this minor accident anyway.

 

[Gasbuggy]

Originally Posted By: wrcsixeight
Anybody else see what appears to be rather extreme inner tire wear?

I guess it could just be the scuffing from after the fact, but if this tire is worn that much on the inside edge, this suspension had issues going back to long before this concrete post attacked your wife's honor, and filled your kids bellies with icecream.


You beat me to it, that is very suspicious. But lets go a step further, from the inside photo it looks like a tire deviation is starting at the top of the picture of the inner sidewall, see the lines in the tire go off to the left. Perhaps at the same spot on the outside from the other picture. I'm having a hard time making a call on this. That EV torque would make for a harder low speed impact but maybe something very harsh happened at a previous time and this hit did it in.

 

[ISO55000]

Originally Posted By: Sunnyinhollister
Greetings,

On Sunday my wife hit a concrete post that the light in a the parking lot sits on. She had parked to the right of it, went into the store came out, started the car started to pull forward, and she said the car veered to the left and ran into the pole. I asked my two sons who were with her and they all had the same story. Basically the car traveled 3 to 5 feet and hit a pole.

When I saw the car the next day (I work nights) the first thing I noticed was very little sheet metal damage and the lower control arm in two pieces. I don't see how a low speed impact of less than 2 or 3 MPH would cause the LCA to break in half without any damage to the strut or bending anything else. From what my wife was saying, it would make sense that the LCA failed causing the car to pull to the left. What say you? I am technically challenegd so I'll post the links to the pics.

Thanks,

Reggie

Not much to say from a failure analysis perspective but I think you may have a cause of action here. You might want to keep those parts and consult an attorney.

If I had all the pieces I could probably say for sure after running magnetic particle testing, microscopy and ultrasonic. Might would even consider an x ray analysis too and possibly make a casting of it to be sure.

It “appears” that this is a porous casting. (A defect) I make that visual estimation from those tiny holes on the right side rib. (Picture pixelates too much to go too far in depth over the internet)

Also, the basic grain looks like this was induced by a shock because there is no visible evidence of any ratcheting or angular stress prior to yield. (Basically an instantaneous failure, not something that bent)Microscopy would answer that question real quick.

I would recommend you contact your local welding contractor or industrial machine shop and let them recommend an AWS weld inspector, a company that does shell testing on pressure vessels/pipes or similar work and let them inspect this and document it.

In any case, normal driving, hitting a speed bump or pot hole (even the family fudging the story a wee bit) should in no way cause this type of failure in a load bearing member.

 

[Sunnyinhollister]

I've been married to the woman for 28 years so I have to believe what she is telling me. No matter what, it was a very low speed impact with just superficial damage to a fender. I noticed the tire wear when I went to take pictures. I did not notice the car pulling one way or the other the last time I drove the car. This may have been a few months ago. Honestly my wife probably would not have noticed the car pulling to one side if it was minor.

Originally Posted By: Trav
When my MIL took Toyota Corolla 4 wheeling and finally hit a set of 5 concrete steps on a house with the L/front it did a lot of damage.

Bent the wheel, bent the subframe, wiped the bumper and radiator support, wiped the fender and bumper out but the control arm still looked okay.
Of course i replaced it with new ball joints and tie rods, the point is the wheel doesn't seem damaged, no impact marks on the control arm either.

If the LCA is that weak to break in half with that little impact (if in fact it was broken due to impact) then IMHO its still a real safety issue.
The LCA could have been holding together by a thread and unloading and loading the suspension just getting in and out could have finished it, who knows.

It shouldn't have with this minor accident anyway.




This was my thought as well. There is no damage to the suspension components as far as I can tell. Nothing is bent or knocked out of place. Even if she had previously hit a curb it should not have caused the part to break in half without any other visible damage.

 

[Sunnyinhollister]

Originally Posted By: ISO55000
Originally Posted By: Sunnyinhollister
Greetings,

On Sunday my wife hit a concrete post that the light in a the parking lot sits on. She had parked to the right of it, went into the store came out, started the car started to pull forward, and she said the car veered to the left and ran into the pole. I asked my two sons who were with her and they all had the same story. Basically the car traveled 3 to 5 feet and hit a pole.

When I saw the car the next day (I work nights) the first thing I noticed was very little sheet metal damage and the lower control arm in two pieces. I don't see how a low speed impact of less than 2 or 3 MPH would cause the LCA to break in half without any damage to the strut or bending anything else. From what my wife was saying, it would make sense that the LCA failed causing the car to pull to the left. What say you? I am technically challenegd so I'll post the links to the pics.

Thanks,

Reggie

Not much to say from a failure analysis perspective but I think you may have a cause of action here. You might want to keep those parts and consult an attorney.

If I had all the pieces I could probably say for sure after running magnetic particle testing, microscopy and ultrasonic. Might would even consider an x ray analysis too and possibly make a casting of it to be sure.

It “appears” that this is a porous casting. (A defect) I make that visual estimation from those tiny holes on the right side rib. (Picture pixelates too much to go too far in depth over the internet)

Also, the basic grain looks like this was induced by a shock because there is no visible evidence of any ratcheting or angular stress prior to yield. (Basically an instantaneous failure, not something that bent)Microscopy would answer that question real quick.

I would recommend you contact your local welding contractor or industrial machine shop and let them recommend an AWS weld inspector, a company that does shell testing on pressure vessels/pipes or similar work and let them inspect this and document it.

In any case, normal driving, hitting a speed bump or pot hole (even the family fudging the story a wee bit) should in no way cause this type of failure in a load bearing member.


I could always send you the two pieces. I really don't believe it to be a wide spread problem but this incident has peaked my curiosity.

 

[ISO55000]

Well, let’s start at the beginning with a few preliminaries and an informal assessment to see if there is cause to do a formal report. (If this does go anywhere I couldn’t assist you officially in Ca. because I’m not licensed there but I have plenty of friends and associates in that region from my personal network who are and I’m pretty sure I can bribe get one to help) I also agree that this is more likely than not just a random isolated situation.

If you would when you have it repaired: (tell whoever does it to please tape cardboard or something over those ends and protect them because secondary damage can render an analysis futile)

Lay something like a white sheet on a table and get something like one of those white LED type shop lights for background lighting.

Prop both pieces together where both sides are showing equally (just like you folded it in half) and get as high res digital camera as you can and with the flash off ( no glare) and take a good close dead on picture and both oblique angles that can be enlarged.

See, fractology testing on any casting as a whole is by “preponderance of the evidence” (the lowest legal standard) because of all of the inherent issues with the casting process. All industry does is cast 2-3 coupons with the batch and test the coupons before QA/QC releases the lot. That may or may not represent an individual cast. There will always be a degree of porosity on any casting just by virtue of the fact it is a liquid poured in a mold.

The only ones I have ever done were on pipe fittings because those have standards and codes attached and there are zillions of one off counterfeits out there. I also know from experience on castings that any analysis is only as strong as the ability of the adverse attorney’s expert’s ability to shoot holes in it and create reasonable doubt should it get that far. That’s not a high bar for casting analysis so even if evidence is there it may not be conclusive enough to stand on. (radically different from standard billets and rolled metals)

What we are looking for on the pictures is this. (For general awareness and entertainment purposes if nothing else)

Metal is wonderful in its ability to hold itself in the failure state. I’m looking to see if those “alleged pores” I saw on the picture you posted are present on the mating fracture surface.

Then we need to look at any oxidation or discoloration in those alleged pores because all castings are porous and if air, moisture, road salts or anything else leached in there and either had a chemical or physical reaction and propagated then the ship hit the iceberg and failure was a guaranteed certainty at that point. It would be just a matter of time to weaken and one little force vector would make it shatter like glass. (Just imagine the average pothole- water and stuff gets in the asphalt and swells, freezes and whatever and pretty soon it cracks and breaks)

Since those alleged pores are on one of the two structural profiles of that member I can easily see not only a significant percentage of strength reduction overall but combined with vectored forces (the normal left and right turning with the vehicle weight and inertia behind it in an alternating pattern) acting against it, I can also see a probable secondary induced torsional stress distributed unevenly because now one side is physically weaker than the other. (Ratcheting left to right and vice versa exerted on the member)

That would be an important observation and should be evident to some degree with the microscope because even though the failure probably happened in a fraction of a second but a lot of things happen in that timeframe.

In theory at least most fractures have a defined start point regardless of the failure mechanism(s) that actually lit the fuse. What we would look for is the grain (think surface of the moon) from the suspected start point toward the end. In most propagation events the grain will appear coarse and somewhat flattened because the micro flexing “worked” it similar to peening it or maybe sanding it and this occurs progressively until the “moment” where the strength is compromised in relation to whatever force is on it then the rest violently yields at once. The delta is during the second phase of failure this grain structure is almost uniform in texture and very fine almost like it was glass beaded.

This happens normally because in that almost nano second the metal did not have the physical time to set in various states from elastic to plastic to separation. (Imagine tearing a piece of plastic from a blister pack- it stretches and deforms and turns white until the leading edge separates then it almost unzips from there. In layman’s terms metal follows that same pattern)

Anyway, that’s the information I would be looking for in those 3 pictures and what it would represent. Hope I didn’t bore you too much because if you are not infected with “the knack” like baby Dilbert (funny video if you google it) engineering is the most dull and uninteresting field there is.

 

[eljefino]

No, that wasn't boring.

 

[hattaresguy]

She smacked it into something, end of story. If I had a dime for every time a women said oh I just bumped the tire and the wheel is smashed to bits...

Love the GM bashing bandwagon that gets rolling so fast.

 

[ls1mike]

Originally Posted By: hattaresguy
She smacked it into something, end of story. If I had a dime for every time a women said oh I just bumped the tire and the wheel is smashed to bits...

Love the GM bashing bandwagon that gets rolling so fast.

LOL. My buddies wife has a Ford 500. Came home with a cracked rim and broken suspension components. Got the "I don't know what happened" Started with I hit a curb at 5 to well I skidded through an intersection going about 30.

I think I told the story here about loaning out my Grand Prix to my wife's friend while I fixed here Subaru.

Got the car back it was making a noise from the front end. Axle, steering rack, Lower A arm were damaged. All had to be replaced after she hit a curb. No biggie the rack had a small weep anyway

.

I had to ask how it happened. Sounds like somehow the traction control got turned off. She laid into 310 hp at the wheels and the car wanted to go one way and she wanted to go the other. Far as I can tell it jumped the curb and landed on the Lower A arm which in turn bent the inner tie rod end and messed up the CV joint. I bet she was going greater than the 20 mph she said. Still have to do the wheel bearing because since the incident I get an intermittent ABS/TCS/Stabilitrack light form that side and wheel sensor.

Let me say this is not specific to women either. But breaking suspension component takes some force in ANYTHING. Not saying you shouldn't believe the Mrs. but it is always not that bad when my wife does something (or buddy for that matter) until I look at it or ride in it and I am like WTH woman? That is bad or that is loud.

 

[wrcsixeight]

ISO55000,

I very much enjoy reading your well written and extremely knowledgeable responses. Thanks for sharing and contributing.

 

[Sunnyinhollister]

Hopefully this link will work to all the pics:

https://www.dropbox.com/sh/weu8qhbib7acwfs/AAAvdwvEMxOQrSoQTa7sLIdwa?dl=0

 

[friendly_jacek]

i think the reason there is so little damage to the fender/bumper, because the wheel took most of the impact. if it was steel it would bend. looks like light metals are less safe in this role.

 

[hattaresguy]

Originally Posted By: ls1mike
Originally Posted By: hattaresguy
She smacked it into something, end of story. If I had a dime for every time a women said oh I just bumped the tire and the wheel is smashed to bits...

Love the GM bashing bandwagon that gets rolling so fast.

LOL. My buddies wife has a Ford 500. Came home with a cracked rim and broken suspension components. Got the "I don't know what happened" Started with I hit a curb at 5 to well I skidded through an intersection going about 30.

I think I told the story here about loaning out my Grand Prix to my wife's friend while I fixed here Subaru.

Got the car back it was making a noise from the front end. Axle, steering rack, Lower A arm were damaged. All had to be replaced after she hit a curb. No biggie the rack had a small weep anyway

.

I had to ask how it happened. Sounds like somehow the traction control got turned off. She laid into 310 hp at the wheels and the car wanted to go one way and she wanted to go the other. Far as I can tell it jumped the curb and landed on the Lower A arm which in turn bent the inner tie rod end and messed up the CV joint. I bet she was going greater than the 20 mph she said. Still have to do the wheel bearing because since the incident I get an intermittent ABS/TCS/Stabilitrack light form that side and wheel sensor.

Let me say this is not specific to women either. But breaking suspension component takes some force in ANYTHING. Not saying you shouldn't believe the Mrs. but it is always not that bad when my wife does something (or buddy for that matter) until I look at it or ride in it and I am like WTH woman? That is bad or that is loud.

My business partners GF "bumped" her new BMW into a pole because she was going the speed limit or slower in the snow of course. $19,856 worth of damage later...

 

[Cujet]

It's not uncommon for race car drivers to lose control of the car, hit the dirt/tire wall/guardrail and have a suspension component break. Then blame the suspension component on the crash.

This is particularly common with rental race cars. I've even been part of a lawsuits involving such.

But, in every case, video and photo's don't lie. The tires are always pointed where the driver points them. The broken suspension is always a result of the impact. Yes, every once in a while, suspension components fail during random times. Often no crash results. So, you can see the issue I have with a part failing under static conditions... Then causing a crash.

I strongly suspect the tires were turned, the tire impacted the pole, the suspension component was then loaded beyond it's capacity and snapped at the thinnest/weakest point.

Consider the likelyhood of a suspension component failing at the point of highest loading, and a casting flaw being located right at that point too. It's much more likely a flaw will be elsewhere, and result in a growing crack over time. Casting flaws are often located near the ends of a casting. Not in the center.

Also, I see no evidence of an inclusion or existing flaw. An existing crack takes time to grow, will have discoloration due to oxidation and will be visually different from the final section of failure.