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Write- Up Diagnosing Death Wobble and Fixing Non-DW Shimmies and Wobbles

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Old 01-16-2013, 12:45 PM
  #11
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Thanks Rob.

Overlander, what I'm saying is that to facilitate the manufacturing process, Chrysler uses a 14 mm bolt in a larger than 9/16" hole and bushing.

Chrysler does not make the axles and axle brackets. They source them.

Chrysler did partially correct the problem on the newer '12s, where the frame side bushing and bracket bolt holes are 14 mm.

Almost no one would disagree that shouldered bolts should be used for applications with a metal bushing sleeve.

And, I have explained that if the bolts are properly torqued and periodically retorqued, it would be rare that the smaller bolt would cause a problem.

The problems happen because retorquing the suspension bolts--primarily the front trackbar bolts--are not part of regularly recommended maintenance, and many JK owners with brand new, unmodified JKs have reported that when taking a torque wrench to their rigs, the bolts were under torqued either at the factory or by the dealer during pre-delivery inspection.

With fully threaded bolts that are smaller than the bushings and the bracket holes, more severe oscillations occur and more damage is done.

Chrysler did a limited recall on some JKs to retorque the front trackbar, blaming a change in paint used caused bolts to loosen up.

It isn't rocket science that bolts stretch and metal fatigues--requiring retorquing of bolts periodically.

So yes, Chrysler should take action and recommend retorquing of the front trackbar bolts at every oil change interval, and yes, they should replace fully threaded bolts with shouldered bolts. However, they won't, because it would cost too much.

Chrysler designed and sold millions of TJs with an inferior front trackbar design that uses a tie rod end at the frame side. They never recalled the TJs.

Instead, they improved the design on the JKs with bolts instead of using a tie rod end, and they use a heavier duty trackbar.

I suggest that fully threaded trackbar and lower control arm bolts be replaced with shouldered bolts. If you are going to do this anyway, you might as well use 9/16" bolts that better fit the bushings and brackets.

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Old 01-16-2013, 02:00 PM
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Originally Posted by OverlanderJK View Post
Wait so your saying that the bolt should be 9/16?


If you torque the bolts to the proper specs you won't have the death wobble and the hole won't bore out making it bigger. I don't think Chrysler would put the wrong bolt size in millions of Jeeps without a recall.
I guess Chrysler wouldnt put in ball joints that wear out in 10k or housings with under engineered C's or axles with soft metallurgy or transmissions with inadequate cooling systems by your logic? I love my Jeep but there are a lot of things they could have done better. Using the right size and type of bolt should have been addressed in '08 not '12.
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Old 01-16-2013, 06:03 PM
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exellant write ups here.
I was thinking about the lack of a manual of the JKs.
I wonder if those manuals are going the way of the do-do bird because of the internet and sharing of information like this.
Thanks!


Might you be able to remember the length of the 9/16" bolts, and how much was threaded?

Rather buy them before crawling under there to swap them out.

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Old 01-16-2013, 06:25 PM
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Originally Posted by homer View Post
exellant write ups here.
I was thinking about the lack of a manual of the JKs.
I wonder if those manuals are going the way of the do-do bird because of the internet and sharing of information like this.
Thanks!


Might you be able to remember the length of the 9/16" bolts, and how much was threaded?

Rather buy them before crawling under there to swap them out.

Thanks

homer
Northridge and Poly both sell a kit with all the bolts you need for the front end.
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Old 01-16-2013, 07:03 PM
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You guys are crazy if you think that the bolt being the wrong size is your problem. But waste your money of you want.
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Old 01-16-2013, 08:29 PM
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Originally Posted by OverlanderJK View Post
You guys are crazy if you think that the bolt being the wrong size is your problem. But waste your money of you want.
First of all, did you read the description of Death Wobble, the inspection checklist, and watch the videos? If so, why are you focusing on such a minor part of the whole?

The bolt size isn't the source of Death Wobble, although it aggravates the problem--poor maintenance, improper installations, and worn or damaged parts.

It's not the bolt size by itself that is the issue, it is that if the torque spec backs off 125 ft lbs, the smaller bolt, combined with the fact that the bolt is fully threaded, results in more violent oscillations that damage bushings and oval out bracket holes--and at times has resulted in trackbar brackets being ripped completely off the frame or axle.

Once you end up with ovaled bracket holes and the bushings have been damaged from the fully threaded bolts, simply retorquing the stock bolts doesn't work as well.

If the bolt size did not matter at all, why did Chrysler in the mid-'12 model year change to a 14 mm bushing and bracket bolt hole on the frame side?

If you can't afford $40 to run shouldered bolts with a better fit in your trackbars and lower control arms and believe it is a waste of money that makes absolutely no difference, more power to you.

I believe that Northridge4x4 now includes the bolt kit at no additional charge with many of the lifts they sell. Why would they do that?

Synergy/Poly Performance has a background in racing. Why do they sell an F911 bolt kit?

Aware of the issue, Rock Krawler designed their flex joints and bushings smaller than factory in order to fit the factory 14 mm bolts. Why would they do that?

Or, could you be right, and the $40 kit is a waste of money, and Chrysler wasted money redesigning the mid-'12's+, and Rock Krawler, Northridge4x4, Synergy/Poly Performance, and I are just over-thinking the importance of a snug fit and/or the use of shouldered bolts in bushing and flex joint ends.

Maybe the $40 would be better allocated to a new steering stabilizer?

Please pardon my sarcasm, but seriously, 12 fine thread bolts, 12 stover lock nuts, and 24 washers (all Grade 8), for $39.95 is hardly a large expenditure.

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Old 01-16-2013, 08:45 PM
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Originally Posted by planman View Post
First of all, did you read the description of Death Wobble, the inspection checklist, and watch the videos? If so, why are you focusing on such a minor part of the whole?

The bolt size isn't the source of Death Wobble, although it aggravates the problem--poor maintenance, improper installations, and worn or damaged parts.

It's not the bolt size by itself that is the issue, it is that if the torque spec backs off 125 ft lbs, the smaller bolt, combined with the fact that the bolt is fully threaded, results in more violent oscillations that damage bushings and oval out bracket holes--and at times has resulted in trackbar brackets being ripped completely off the frame or axle.

Once you end up with ovaled bracket holes and the bushings have been damaged from the fully threaded bolts, simply retorquing the stock bolts doesn't work as well.

If the bolt size did not matter at all, why did Chrysler in the mid-'12 model year change to a 14 mm bushing and bracket bolt hole on the frame side?

If you can't afford $40 to run shouldered bolts with a better fit in your trackbars and lower control arms and believe it is a waste of money that makes absolutely no difference, more power to you.

I believe that Northridge4x4 now includes the bolt kit at no additional charge with many of the lifts they sell. Why would they do that?

Synergy/Poly Performance has a background in racing. Why do they sell an F911 bolt kit?

Aware of the issue, Rock Krawler designed their flex joints and bushings smaller than factory in order to fit the factory 14 mm bolts. Why would they do that?

Or, could you be right, and the $40 kit is a waste of money, and Chrysler wasted money redesigning the mid-'12's+, and Rock Krawler, Northridge4x4, Synergy/Poly Performance, and I are just over-thinking the importance of a snug fit and/or the use of shouldered bolts in bushing and flex joint ends.

Maybe the $40 would be better allocated to a new steering stabilizer?

Please pardon my sarcasm, but seriously, 12 fine thread bolts, 12 stover lock nuts, and 24 washers (all Grade 8), for $39.95 is hardly a large expenditure.

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Old 01-17-2013, 03:46 AM
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So, planman, how would one know if he has a Jeep that has had this issue addressed with the smaller bushings and frame holes? Pull one of the bolts and measure the bushing/hole? If they were indeed 14mm, would I be safe to say all of them are?

I ask because I could see this being a possible fitment issue with lift kit components. Are most lift kits setup to accept the factory 14mm bolts, or upsized to 9/16"? Say I didnt have the upgraded mounts/bushings and I bought the larger bolts for them, would I have issues with some lift kit components (like the Rock krawler joints by the sounds of it)?
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Old 01-17-2013, 04:22 AM
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Originally Posted by planman View Post
First of all, did you read the description of Death Wobble, the inspection checklist, and watch the videos? If so, why are you focusing on such a minor part of the whole?

The bolt size isn't the source of Death Wobble, although it aggravates the problem--poor maintenance, improper installations, and worn or damaged parts.

It's not the bolt size by itself that is the issue, it is that if the torque spec backs off 125 ft lbs, the smaller bolt, combined with the fact that the bolt is fully threaded, results in more violent oscillations that damage bushings and oval out bracket holes--and at times has resulted in trackbar brackets being ripped completely off the frame or axle.

Once you end up with ovaled bracket holes and the bushings have been damaged from the fully threaded bolts, simply retorquing the stock bolts doesn't work as well.

If the bolt size did not matter at all, why did Chrysler in the mid-'12 model year change to a 14 mm bushing and bracket bolt hole on the frame side?

If you can't afford $40 to run shouldered bolts with a better fit in your trackbars and lower control arms and believe it is a waste of money that makes absolutely no difference, more power to you.

I believe that Northridge4x4 now includes the bolt kit at no additional charge with many of the lifts they sell. Why would they do that?

Synergy/Poly Performance has a background in racing. Why do they sell an F911 bolt kit?

Aware of the issue, Rock Krawler designed their flex joints and bushings smaller than factory in order to fit the factory 14 mm bolts. Why would they do that?

Or, could you be right, and the $40 kit is a waste of money, and Chrysler wasted money redesigning the mid-'12's+, and Rock Krawler, Northridge4x4, Synergy/Poly Performance, and I are just over-thinking the importance of a snug fit and/or the use of shouldered bolts in bushing and flex joint ends.

Maybe the $40 would be better allocated to a new steering stabilizer?

Please pardon my sarcasm, but seriously, 12 fine thread bolts, 12 stover lock nuts, and 24 washers (all Grade 8), for $39.95 is hardly a large expenditure.

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Thanks Planman,

Great to have you back. I agree $40 is nothing compared to what would have to be replaced by not doing it. Does not make sense with the bolts they used. You could almost compare that to....well, I don't need an oil change I'll just top it off as I go.
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Old 01-17-2013, 07:02 AM
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Originally Posted by olyelr View Post
So, planman, how would one know if he has a Jeep that has had this issue addressed with the smaller bushings and frame holes? Pull one of the bolts and measure the bushing/hole? If they were indeed 14mm, would I be safe to say all of them are?

I ask because I could see this being a possible fitment issue with lift kit components. Are most lift kits setup to accept the factory 14mm bolts, or upsized to 9/16"? Say I didnt have the upgraded mounts/bushings and I bought the larger bolts for them, would I have issues with some lift kit components (like the Rock krawler joints by the sounds of it)?
Even with the mid year '12s+, Chrysler only made the frame side holes smaller. The axle side remains larger than 9/16".

I believe that only Rock Krawler and Trailmaster (which sources RK joints) has built 14 mm flex joint ends. I know that Currie, Teraflex, JKS, Synergy/Poly Performance, and most others have 9/16" bushings & flex joint ends.

The way to determine whether you have an issue is to remove your front trackbar and inspect the bracket holes for ovaling and the bushing bolt sleeves for evidence that the bolt threads have eaten deep grooves into the metal. If none of this has happened, you could just reinstall the trackbar and torque the bolts to spec.

However, if you have a shouldered, fine thread, Grade 8 bolt to test fit in the bushing and the bracket hole, it would make sense to go ahead and use the upgraded hardware when you reinstall the trackbar.

Then, as part of regular maintenance, retorque the front trackbar at every oil change interval and after every major offroading trip (i.e. after a week in Moab, before you drive home). Periodic retorquing of the control arm bolts is a good idea, but not as critical as the front trackbar.


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