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Discussion Starter · #21 ·
MitchT said:
I feel like putting safety wire, tabs and paint on all my bolts but I am parinoid about stuff falling off on the track. Nut and bolt the suspension before tracking.
How small do they make lojack type radio transmitters? j/k
 

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xtn said:
I know of one other owner who discovered - not that the bolt heads had snapped off - but simply that the nuts had backed off. I'm talking about the two upper a-arm mounting bolts. One of his bolts was completely missing and the other had no nut on it at all.
Nuts?
 

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Randy Chase said:
Control arm to chassis in this case - we misunderstood.

Guessing, due to your question, that this thread is about the ball joint carrier to the hub carrier?
 

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Discussion Starter · #25 ·
codymac said:
Control arm to chassis in this case - we misunderstood.

Guessing, due to your question, that this thread is about the ball joint carrier to the hub carrier?

I think you are talking about the same part that I am. I found this pic on the sands museum website, but i don't have the software to draw arrows. the bolts that broke are beneath the ball joint and attach to the hub carrier behind the rotor. (I think).

Motor vehicle Technical drawing Auto part Drawing Line art
 

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MitchT said:
Nut and bolt the suspension before tracking.
And do the same to your wife before you head out to the track for the weekend.

xtn
 

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In my case it was the bolts pictured here that broke causing the control arm to seperate. (there are actually 2, only one is pictured) These are the bolts you would remove if you were to pull your shims.

I have always suspected that they were not torqued on properly which should be a part of the PDI ritual then checked again at first service since it is an obvious problem. This ultimately led to them loosening then breaking.
 

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Discussion Starter · #29 ·
Chris said:
In my case it was the bolts pictured here that broke causing the control arm to seperate. (there are actually 2, only one is pictured) These are the bolts you would remove if you were to pull your shims.

I have always suspected that they were not torqued on properly which should be a part of the PDI ritual then checked again at first service since it is an obvious problem. This ultimately led to them loosening then breaking.
So yours were on the front.... :confused:

Maybe Lotus should start checking all of these on the cars that come through their shops? I'm not sure what the actual incidence of this is, but considering that each one could theoretically cost Lotus thousands, (if not much more in the situation of a fatality occurring as a result) and checking each car would be relatively cheap, it might be a good idea that they do this. Just a thought. Are you listening Lotus?
 

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OOOOH

The owner I mentioned previously had problems with the top wishbone to chassis bolts. Not the same issue.
 

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I was curious, so went out and took a look at mine. You're able to view them without removing wheels, so I grabbed a couple pictures, one of each side's top rear inboard control arm bolt. What I find interesting is that the rotation-stop-flanges appear ineffective, or perhaps just improperly used. Note the green paint - the bolts have rotated sometime after assembly. None of the bolts are protruding through what appears to be lock nuts on the ends. This is not very encouraging, looks like I need to rebuild all these joints with new bolts and new anti-rotation plates? Or am I just being overly paranoid?
 

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I think you guys are reading the paint marks wrong.

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

carlover said:
I think you are talking about the same part that I am. I found this pic on the sands museum website, but i don't have the software to draw arrows. the bolts that broke are beneath the ball joint and attach to the hub carrier behind the rotor. (I think).
Nah... xtn and I were talking about where the A-arm meets the chassis (the photos above showing the bolts with tabs).
 

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Chris said:
In my case it was the bolts pictured here that broke causing the control arm to seperate. (there are actually 2, only one is pictured) These are the bolts you would remove if you were to pull your shims.

I have always suspected that they were not torqued on properly which should be a part of the PDI ritual then checked again at first service since it is an obvious problem. This ultimately led to them loosening then breaking.
According to the service manual, the bolts you showed (whether front or rear wheels) are supposed to be secured with a thread locker (Loctite or equivalent). However, when I removed the shims on my front wheels, I noticed that the bolts had NO thread locker. Apparently the factory doesn't always follow its own rules. When I put the bolts back, I did use thread locker. Maybe I'll remove the rear ones now and put them back using Loctite, just to be safe.

Of course, that doesn't matter if the heads pop off. Stronger bolts required?
 

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ChrisH said:
Maybe I'll remove the rear ones now and put them back using Loctite, just to be safe.
Probably not a bad idea.

ChrisH said:
Of course, that doesn't matter if the heads pop off. Stronger bolts required?
Maybe the heads pop off from being over tightened? Mine broke further down the bolt, not at the head.
 

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Chris said:
I had the exact same thing happened to me at the track, except my wheel folded over mid corner!

The car spun 90 degrees and I let the car roll backwards off of the track to get out of the other drivers way. Fortunately I did not hit anything and there was no body/frame damage. It was towed to the dealership and they replaced everything in the rear suspension under warrenty. I just pray it never happens again! I was actually glad it happened at the track and not on a highway off-ramp in traffic!

Everyone should pull off their wheels and check the torque on the 2 bolts that hold the upper control arm together. I had the mechanic put paint on the new bolts so I can visually confirm they are not moving.

Sorry to hear it happened to you, I don't think it is all that common.
<Threadjack>
Chris when did this happen? :crazyeyes
</Threadjack>
 

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Discussion Starter · #37 ·
MattG said:
I was curious, so went out and took a look at mine. You're able to view them without removing wheels, so I grabbed a couple pictures, one of each side's top rear inboard control arm bolt. What I find interesting is that the rotation-stop-flanges appear ineffective, or perhaps just improperly used. Note the green paint - the bolts have rotated sometime after assembly. None of the bolts are protruding through what appears to be lock nuts on the ends. This is not very encouraging, looks like I need to rebuild all these joints with new bolts and new anti-rotation plates? Or am I just being overly paranoid?
Thanks for the pics, Matt, and NO I don't think you're being paranoid. If this thing comes apart on a highway or other high speed scenario or near other cars, the results could be tragic.

When I talk to the good folks at the service center I will talk to them about this. If they don't do it, I will.
 

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Discussion Starter · #38 ·
ChrisH said:
According to the service manual, the bolts you showed (whether front or rear wheels) are supposed to be secured with a thread locker (Loctite or equivalent). However, when I removed the shims on my front wheels, I noticed that the bolts had NO thread locker. Apparently the factory doesn't always follow its own rules. When I put the bolts back, I did use thread locker. Maybe I'll remove the rear ones now and put them back using Loctite, just to be safe.

Of course, that doesn't matter if the heads pop off. Stronger bolts required?
There is certainly a lot of info in that little book.

Good call on the Loctite. :up:

In regards to the "stronger bolts," how do we know what bolts are used in th factory, and therefore which "aftermarket" bolts would be stronger?
 

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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.



Chris said:
Probably not a bad idea.



Maybe the heads pop off from being over tightened? Mine broke further down the bolt, not at the head.
 
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