[MattG]

I think you guys are reading the paint marks wrong.

Two marks - one for torque and one for "yeah, I hammered the tab over."

Interesting theory. I'll have to take a look at similar tabs elsewhere on the car. One thing to note though is that in each place, only one of the two locking tabs has been bent over. Why not bend both for twice the security?

In all fairness, there's one thing I can't rule out - there's a possibility that, when I took the car in for its 1k service, the tech bent the tab away, torqued that bolt, and bent the tab back. The only scenario I see a tech actually doing this, though, is if they notice the bolt has loosened already. Otherwise, if the green line is all lined up, why mess with it?

 

[carlover]

Interesting theory. I'll have to take a look at similar tabs elsewhere on the car. One thing to note though is that in each place, only one of the two locking tabs has been bent over. Why not bend both for twice the security?

In all fairness, there's one thing I can't rule out - there's a possibility that, when I took the car in for its 1k service, the tech bent the tab away, torqued that bolt, and bent the tab back. The only scenario I see a tech actually doing this, though, is if they notice the bolt has loosened already. Otherwise, if the green line is all lined up, why mess with it?

Good question.

 

[MattG]

Also, note that in the first picture, the 'tooth' of that locking tab appears to be slipping off of the chassis member there, doing little to actually prevent rotation.

 

[Chris]

Chris when did this happen? :crazyeyes

It was one year ago almost to the day at Dunnville. My car was fully restored and running in around a week thanks to Gentry Lane.

I have posted a video clip this afternoon on Google video but it is taking forever to process. As soon as its done I will link to it from this thread.

 

[Chris]

So yours were on the front....

No, rear Passenger side.

 

[Chris]

Google finally finished processing the Video, here is the link.

This is the video of my upper control arm bolts breaking off mid-corner. It happened in June 2006 at the Dunnville Autodrome.

http://video.google.ca/videoplay?docid=-8857507290621297172&hl=en-CA

 

[raggedy1]

without looking it up myself, can someone post the torque spec for these bolts?

mattg, we had our cars serviced at the same dealership, and to be honest, I don't think they checked ANY torque specs on my car. the toe link loosening problem wasn't even recognized yet when our cars were in for the 1k service.

I think a lot has been learned over the past 3 years. I would guess that many bolts are now being checked for proper tightness.

 

[Seb]

I see in the video your wheel was the outside wheel that broke. On Joes Elise, it was the inside wheel. Left side turning left.

WOW that sucks! "hey i didn't go off the track" ahahaha

 

[carlover]

No, rear Passenger side.

The image you attached diagrammed the steering linkage, was this intentional?

Just saw the video, btw, great post. Thanks for the clip. The way yours broke makes sense as it was on the loaded wheel (not that it should have happened) but mine was on the inside wheel. So while the problem is the same, I cannot understand the physics behind what happened to my car, unless the bolt was so fatigued that the slight stress caused by driving over the reflector coupled with the stress of acceleration.

Thanks again,

Joe

 

[MattG]

mattg, we had our cars serviced at the same dealership, and to be honest, I don't think they checked ANY torque specs on my car. the toe link loosening problem wasn't even recognized yet when our cars were in for the 1k service.

I don't fault them. This whole idea of having to check the torque of all the suspension bolts is frankly a little ridiculous; it's not something that modern automobile technology should require. Especially from a company that is known for its automotive engineering consulting business. Even the bolt in question whould not normally need to be checked, not with the locking plate there. It sounds like more of a manufacturing issue, not something the dealers should have been looking out for.

Whatever the case, it's frustrating to lose confidence in my car when issues like this come up.

 

[carlover]

I don't fault them. This whole idea of having to check the torque of all the suspension bolts is frankly a little ridiculous; it's not something that modern automobile technology should require. Especially from a company that is known for its automotive engineering consulting business. Even the bolt in question whould not normally need to be checked, not with the locking plate there. It sounds like more of a manufacturing issue, not something the dealers should have been looking out for.

Whatever the case, it's frustrating to lose confidence in my car when issues like this come up.

I think that the dealers should become aware of this potential problem and should start checking these bolts.

When I get my car back you bet I'll be going through it with a fine toothed torque wrench :huh:

 

[xtn]

I'm really glad that happened on what appears to be a closed track, but if you don't stop calling them upper control arm bolts I might change my mind....

Google finally finished processing the Video, here is the link.

This is the video of my upper control arm bolts breaking off mid-corner. It happened in June 2006 at the Dunnville Autodrome.

http://video.google.ca/videoplay?docid=-8857507290621297172&hl=en-CA

 

[Seb]

Totally agree... this is BS.

 

[raggedy1]

I agree MattG. I don't fault the dealers, especially back in late 04 when early cars were going in for their 1k service.

But now that Lotus and its dealers are aware of potential problems I believe they are watching for issues like loosening bolts. I know SVAG checks the toe link torque at the 7.5k service.

 

[Chris]

The image you attached diagrammed the steering linkage, was this intentional?

Not intentional, it was the only image I could find, same bolts though I think. Sorry for the confusion.

 

[Chris]

I'm really glad that happened on what appears to be a closed track, but if you don't stop calling them upper control arm bolts I might change my mind....

Lol, not sure what they are actually called, Hub Carrier bolts maybe? Sorry if I mislead anyone with the incorrect description.

 

[ChrisH]

Chris, yours broke because one backed off,the mount became loose and that excess load of only one bolt holding the mount. I check the torque on my outer upper A arms when I check the rear toe link, once a month. I have not noticed the upper A arm bolts getting loose, but I did locktite them after removing the shims.
Regarding the paint....yes, it is there to identify that the process was competed and checked, not as a referance to bolt movement.

Another way that the hub (shim) bolts might be breaking is if they come loose, even a little (a millimeter or two), the hub will shift suddenly as the car shifts side to side in during handling. The bolt will stop the hub when it reaches the head, which will cause sudden hard shocks to the bolt and could eventually snap it. The shock force can be much greater than if the bolt is tight because in the tight case, it picks up the load gradually due to the tire dampening the side to side onset of force a bit. Even if only one bolt is loose, the flange (that bolts to the hub) can shift at that bolt location (it twists around the tight bolt). Hence, I wouldn't be surprised if the slightly loose bolt breaks before the tight one does. If the bolt manages to get very loose without breaking (too far out for the bolt head to be hit with a shock), then I would expect the secure bolt to break first.

 

[R'elise Me]

Those bolts require loctite whenever you realign the camber. I can't see how that bolt can walk out with proper loctite. I always wirebrush the old loctite off and clean with solvent prior to reinstalling with new loctite. With loctite, I believe the torque setting is not critical but I'm not positive. Anyone have the torque spec?

 

[neckstrap]

You guys are confusing me. I admit it's not that hard to do.

But, did the hex headed bolts that go through the rubber control arms break OR did the allen headed bolts that hold the tie rod link onto the hub carrier break OR both?

In either case, I cannot determine if the bolts are "graded". The best solution for breaking fasteners is to replace them with higher "graded" fasteners. I can buy grade 8 bolts like these at Home Depot for about $1.50 each. The allen headed bolts are a little more. But, why not replace them? And why hasn't lotus issed a recall to replace all of them under warrenty? Maybe we all need to start a writing campaign? This is a serious safety concern.

Paul

 

[mlk_f1]

Mannnnnn, yet another suspensioon part issue ??? Sucks, this really give me lots of confidence on the track.
So, is this due to improper torque on the bolts or is it a bolt strength problem or both??

Sector111 please come to the rescue.