US Gov't/NHTSA addresses Jeep Death Wobble - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > General Jeep Discussions > General Jeep Discussion

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 03-20-2012, 09:35 PM   #1
Jeeper
 
jetskier111's Avatar
 
Join Date: Feb 2012
Location: Athens, Ga
Posts: 210
Images: 3
US Gov't/NHTSA addresses Jeep Death Wobble


__________________
The way to end a frustrating day in grad school? Find a trail and get lost in it.
jetskier111 is offline   Quote Quick Reply
Old 03-21-2012, 01:58 AM   #2
Supporting Member

WF Supporting Member
 
planman's Avatar
 
Join Date: Jan 2011
Location: Billings, MT
Posts: 324
I have written Dan Noyes more than once about this.

This was my response on Dan Noyes' Facebook page (he is the ABC investigative reporter that did the story and facilitated the letter from his local representative and Congressman Waxman to the NHTSA).




It is all fairly simple with the JK.

The stock front trackbar bolts need to be torqued to 125 ft. lbs. Re-torquing them to 125 ft. lbs. needs to be part of the dealership pre-delivery inspection and part of the recommended maintenance at every oil change interval.

What happens over time with suspension cycling, road/tire vibrations, and the natural elasticity of metal, is that the torque specs back off a little on some jeeps.

Because Chrysler used stock trackbar bolts that are 14 mm instead of the 9/16" size bracket bolt holes, there is slop of the stock bolts in the stock brackets if the torque specs back off of 125 ft. lbs. Except for the very newest 2012 JKs, all the rest of the JKs have trackbars with bushing end bolt sleeves that are also 9/16"--large enough compared to the 14 mm stock bolts that there is slop when the torque specs back off from 125 ft. lbs.

With the amount of slop in the bracket bolt holes and the trackbar bushings, when the torque specs are less than 125 ft. lbs. it leads to violent, tear-your-front-end-apart Death Wobble with the right kind of trigger to throw the front end into that harmonic oscillation--like railroad tracks, poorly balanced tires, bridge seams, etc.

The stock steering dampener attempts to mask the looseness in the trackbar ends/brackets/bolts, but eventually, it fails prematurely.

The uninformed driver continues to drive the jeep with Death Wobble.

Multiple episodes of Death Wobble end up damaging most of the rest of the front end. The loose bolts oval/wallow out the trackbar bracket holes and damage the trackbar bushings. One or more of the lower ball joints fail, the tie-rod and drag link ends fail, the unit-bearings fail, the steering box fails, and the front upper axle side control arm bushings fail. It is not uncommon for the trackbar bracket welds at the frame and the axle to crack. I have seen brackets ripped clear off the frame and/or the axle when owners continue to drive a JK with Death Wobble.

In addition to the first simple solution of adding re-torquing the front trackbar at pre-delivery, and later, after every oil change interval, the second solution is for Chrysler to properly train their techs how to inspect for and diagnose the source(s) of Death Wobble. Unfortunately, Chrysler simply gives them a Technical Service Bulletin (TSB) to upgrade the steering dampener. They do not train them to follow an inspection checklist to look at the trackbar bushings, trackbar bracket bolt holes, ball joints, unit-bearings, tie-rod ends, drag link ends, steering box and sector shaft, control arm bushings, trackbar bracket welds, etc. The alignment specs also can aggravate the problem if there is too much or too little toe-in or caster.

A new TSB with a comprehensive inspection checklist should also consist of switching out the too small 14 mm trackbar bolts with 9/16" Grade 8 fine thread bolts that actually fit the brackets and bushing ends.

The new, heavy duty steering dampener eventually fails just like the original one when it can no longer mask the true source(s) of the Death Wobble.

Where the JK Death Wobble most often starts with trackbar bolts that aren't torqued to spec, and then is severely aggravated by stock bolts that are much too small for the stock bolt holes and bushings ends, the TJ Wrangler most often starts with the trackbar for a different reason.

The TJ Death Wobble most often happens because the frame side end of the trackbar has a tie-rod end instead of a bushing end (like the JK does). The tie-rod end is designed for rotational movement, but it does not allow side-to-side movement. However, when the suspension flexes in a TJ, the leverage of the trackbar against that end results in wearing out and destroying the end. That is why in the ABC story, the 4x4 repair shops/vendors quoted recommend a different design for the attachment at the frame side end. It addresses the problem of that tie-rod end design binding when the suspension flexes.

I could explain a lot more, but these are the basic issues at hand here. I am no engineer. I am just a weekend hobbyist, but most every engineer and mechanic/alignment tech who has read my explanations and inspection checklist agree that a loose trackbar on a solid front axle vehicle with coil springs and control arms will result in Death Wobble problems--even if the tires are perfect and the alignment within spec.

Again, Chryslers' response needs to be:

1- an update to pre-delivery inspection at the dealer to re-torque at least the trackbar bolts
2- an update to the recommended service schedule to include re-torquing the front trackbar at every oil change interval
3- a Technical Service Bulletin (TSB) that properly trains dealer technicians to do a thorough inspection of all the front end links, components, ends, bushings, steering, ball joints, etc., and to replace the front 14 mm trackbar bolts with 9/16" bolts. It should add inspection for proper caster and toe alignment specs, and it should include inspection of the wheels/tires as aggravating triggers to the Death Wobble. Only after the true source(s) of the problems are addressed, then the TSB would recommend the installation of a new steering dampener.

In spite of all this, you need to know that Death Wobble almost never happens on a properly maintained jeep--whether it is stock or modified.

__________________

His: 07 JK Rub 2 dri, 6 spd, 5.38s in Currie RJ 60s, 4.5" Trailmaster long arm with 99" wheelbase, 40" Xterrains on ATX Slabs, River Raider cage, RIPPd
Hers: 08 JK Rubi 4 dr, auto, 5.38s, Teraflex LA w/ORE/King coilovers, 37" STTs on WE beadlocks, RIPPd
planman is offline   Quote Quick Reply
Old 03-22-2012, 01:37 PM   #3
Jeeper
 
Join Date: Nov 2011
Location: north jersey
Posts: 513
does this mean my 2012 does not have this bolt problem?
blackforestgreen is offline   Quote Quick Reply
Old 03-23-2012, 08:00 AM   #4
Jeeper
 
GreenRubi's Avatar
 
Join Date: Jul 2011
Location: Raleigh, NC
Posts: 480
The 2012 ALSO has this problem. Please see:

http://www.wranglerforum.com/f33/the...ts-128154.html

This thread has a lot of good information on this issue and details on purchasing replacement bolts for your TBs and LCAs. I bought mine local and switched them out myself. It is a pretty straight forward upgrade. Just be sure you have a good torque wrench. A pneumatic impact wrench is a great help too.

Here is one link for replacement bolts:
http://www.polyperformance.com/shop/...t-p-28601.html
__________________
2008 Natural Green JK Rubicon
GreenRubi is offline   Quote Quick Reply
Old 04-02-2012, 06:56 PM   #5
Newb
 
Join Date: Nov 2010
Location: Shinglehouse, PA
Posts: 8
thanks for this. I have a 2007 that I bought used last year. I continue to have this "death wobble" even after having it to the dealer several times and them saying everything is ok. Now I have ammo to get them to fix the problem.
pakev45 is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Jeep newbie -- Sahara or Rubicon? snikt JK General Discussion Forum 60 05-09-2014 04:00 PM
Autoblog: Congress investigating Death Wobble Rubicon_Jim JK General Discussion Forum 68 03-24-2012 09:29 PM
New Jeep peeps in Michigan studlypotato WF New Member Check In 16 03-23-2012 02:46 PM
New Jeep Plastidip Fun Yantzie JK General Discussion Forum 4 03-20-2012 11:05 PM
Carrying chains W/Jeep marc10000 JK General Discussion Forum 5 03-20-2012 08:53 PM



» Featured Product

All times are GMT -5. The time now is 08:31 PM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC