Failed Bolt - Suspension Arm

[j.ironfab]

Sounds like we have some similar experience in the Jeeping world, and I'm always interested in learning more. Could you clarify what you are describing in the sentence I pasted in (above). It makes me think I'm missing something. I've installed a handful of suspension lifts - both on my own vehicles and helping out friends (its the best way to get free beer now that I'm too old to have strangers buy me drinks at the bar). I can think of one bolt at each end of each control arm - not two.

There are usually two bolts connecting the front-end bracket for the rear lower control arm to the frame, but just one bolt running through the bracket and the joint of the control arm itself. Below is an image of a rear lower control arm from a Jeep JK - its a similar design to the Grenadier, and its the same arm in which the bolt failed in the truck owned by @pete54. At each end of the arm, we see a hole for a single bolt passing through the joint. If you were to lose one of these bolts while highway driving, the control arm might stay in place, but the loose end could also drop down to the pavement, resulting in some significant problem. Real question: am I misinterpreting your post, or am I missing something else?

Typical rear lower control arm (this one from a Jeep JK):

View attachment 7840917

Rear joint of the rear lower control arm - from the original post:
View attachment 7840918

I am guessing this was a mistake of phrasing. The bolt count was correct 8 bolts for the 4 link but just should have been two bolts one at each end of the link. Both ends of the gren are non triangulated 4 links so you also have a panhard that centers the axles side to side. So technically there are 10 bolts that control the axle in its movement.

 

[255/85]

Sounds like we have some similar experience in the Jeeping world, and I'm always interested in learning more. Could you clarify what you are describing in the sentence I pasted in (above). It makes me think I'm missing something. I've installed a handful of suspension lifts - both on my own vehicles and helping out friends (its the best way to get free beer now that I'm too old to have strangers buy me drinks at the bar). I can think of one bolt at each end of each control arm - not two.

There are usually two bolts connecting the front-end bracket for the rear lower control arm to the frame, but just one bolt running through the bracket and the joint of the control arm itself. Below is an image of a rear lower control arm from a Jeep JK - its a similar design to the Grenadier, and its the same arm in which the bolt failed in the truck owned by @pete54. At each end of the arm, we see a hole for a single bolt passing through the joint. If you were to lose one of these bolts while highway driving, the control arm might stay in place, but the loose end could also drop down to the pavement, resulting in some significant problem. Real question: am I misinterpreting your post, or am I missing something else?

Typical rear lower control arm (this one from a Jeep JK):

View attachment 7840917

Rear joint of the rear lower control arm - from the original post:
View attachment 7840918

4 arms - one bolt at each end = 8 bolts.

Sorry for the confusion. I should have written "one at each end of each control arm". It's like English is my second language sometimes. I mostly converse in grunts and lazy lackluster hand gestures. Anyway...

As long as you don't lose more than one bolt (which is the equivalent of losing the functionality of one complete arm), you probably won't fare too badly. The two arms on the other side - one upper and one lower - will mostly prevent the rear axle assembly from rotating, well, axially. Those two, with the remaining third arms, will mostly keep it from changing its position in relation to the vehicle frame.

I guess if the leading edge of a control arm dropped down to ground level at speed, and then impaled itself into a large pothole or other immovable object, you might pole vault the vehicle upward a bit. I would think that the combined weight and momentum of the vehicle would probably just sheer the other bolt clean off but I really have no idea. I do seem to remember urban legends of vehicles flipping because of a front u-joint failure on a rear driveshaft/propshaft while said vehicle was traveling at a highway speed.

I am guessing this was a mistake of phrasing. The bolt count was correct 8 bolts for the 4 link but just should have been two bolts one at each end of the link. Both ends of the gren are non triangulated 4 links so you also have a panhard that centers the axles side to side. So technically there are 10 bolts that control the axle in its movement.

Absolutely agreed. it appeared to me there is some very minor triangulation created by each upper/lower pairing of control arms in the single demo vehicle I looked at, but not enough to do without the rear Panhard bar (or front track bar!). I was trying not to muddy the issue. So, yes - 10 bolts.

Of those twenty (10 front, 10 rear), the two holding the front track bar in place would be my biggest concern. Loose that and your steering box has little to work against.

Edited to not sound illiterate.

 

[pete54]

Delighted to get my Grenadier back today and a huge thanks to Ineos Grange Edinburgh for getting it through as quickly as they could. They ordered the bolts as a priority from Ineos first thing on Monday but didn’t arrive with them until yesterday afternoon. It’s a work vehicle for me so a day longer and I would have had serious problems as it’s needed tomorrow.

The general consensus seems to be over torquing at assembly. Hopefully this is a one off globally!

Hopefully the delivery of parts gets faster from here on in.

 

[AMD66]

Delighted to get my Grenadier back today and a huge thanks to Ineos Grange Edinburgh for getting it through as quickly as they could. They ordered the bolts as a priority from Ineos first thing on Monday but didn’t arrive with them until yesterday afternoon. It’s a work vehicle for me so a day longer and I would have had serious problems as it’s needed tomorrow.

The general consensus seems to be over torquing at assembly. Hopefully this is a one off globally!

Hopefully the delivery of parts gets faster from here on in.

Let’s hope they are correct re assembly rather than a bigger issue, glad you spotted the bolt on the deck, it could have been a lot worse !

 

[moosetown]

I find it weird they used cam bolts

 

[Miki]

I find it weird they used cam bolts

Me too.

 

[DrahthHunter]

I hear your frustration, but I think you are missing an important point: its worse if Ineos knew about it!

If it was a known problem, there should have been a recall, and a "Do Not Drive Until Fixed" message put on full blast.

The failure to put out such a notice could have resulted in someone's death. That's not hyperbole. @pete54 is damn lucky the bolt fell out of his vehicle while it was parked in his driveway. Had the bolt failed while doing 80 mph on the highway, things could have gone very badly. If - as you have indicated - Ineos knew about the problem and did not recall his vehicle, they would be in serious trouble.

It would be nice to measure that bolt to see how stretched it is, and inspect the other side. The zink is gone that bolt looks molested

 

[DrahthHunter]

And how much have the technicians been brought up to speed ? I have the utmost respect for Styer & Magna but do they even have technicians here? I think the NA operation has a lot to be desired with staffing.

 

[NQ94]

It would be interesting to see if the bolt galled during tensioning and a torque value was achieved too early and before enough clamping force was applied to the joint leading to a fatigue failure of the bolt. A manufacturing defect cannot be ruled out and can also contribute to the bolt failure. Some coatings used on fasteners are known to have a higher risk of binding during the tensioning phase that may not be detected if using impact or powered torque tools.

 

[Tinerfeño]

As long as you don't lose more than one bolt (which is the equivalent of losing the functionality of one complete arm), you probably won't fare too badly. The two arms on the other side - one upper and one lower - will mostly prevent the rear axle assembly from rotating, well, axially. Those two, with the remaining third arms, will mostly keep it from changing its position in relation to the vehicle frame.

While changing bushes to arms we can remove one arm and leave the axle for a while, posssibly adding wedges to both sides of the wheel in the side in question. But it certainly is not driveable because the flexible bushes allow the axle to move in any direction (lateral and rotational). Which also causes excessive loads on the pair of missing arm.

 

[rovie]

I actually thought I would have a Grenadier-free Sunday. But after seeing this screw topic, I think I'll have to take my Series IIa off the lift and inspect the Grenadier from underneath again. It seems to me that the regular inspection is in addition to the regular lubrication of the door locks.

 

[Tazzieman]

I actually thought I would have a Grenadier-free Sunday. But after seeing this screw topic, I think I'll have to take my Series IIa off the lift and inspect the Grenadier from underneath again. It seems to me that the regular inspection is in addition to the regular lubrication of the door locks.

How will you test that bolt?

 

[rovie]

How will you test that bolt?

I cannot test the bolt. But I can see whether the bolt has also been torn off in the meantime and will soon come out. And other fastenings too.

 

[Tazzieman]

I cannot test the bolt. But I can see whether the bolt has also been torn off in the meantime and will soon come out. And other fastenings too.

Will you check it next week?
It might be "on the edge"

 

[rovie]

Will you check it next week?
It might be "on the edge"

No, that's too late. Tonight and then after every single journey.

 

[Tazzieman]

No, that's too late. Tonight and then after every single journey.

Excellent. OCD is the best quality control out there!

 

[255/85]

I find it weird they used cam bolts

I'm assuming they did so to correct manufacturing variances and/or aid with setting the rear pinion angle.

 

[bigleonski]

No, that's too late. Tonight and then after every single journey.

Might I suggest BEFORE every journey may be wiser.

 

[rovie]

Might I suggest BEFORE every journey may be wiser.

After the journey is before the journey.