Congress Critters Ask NHTSA to Investigate Death Wobble
03-20-2012, 02:12 PM
#1
JK Super Freak
Thread Starter
Congress Critters Ask NHTSA to Investigate Death Wobble
http://www.autoblog.com/2012/03/20/j...s-of-congress/
Someone should tell Congress about Jeep inexplicably under-sizing JK suspension bolts. 
A local television news report on a so-called Jeep "death wobble" has led two members of the House of Representatives to write a letter to the National Highway Traffic Safety Administration requesting more information about the situation, which they describe as a "serious safety issue." The three-page letter does not demand an investigation or recall, but asks the agency numerous questions regarding the problem and what is known about it. The original report aired on KGO-TV in San Francisco in February.
The two members of Congress describe the problem as "a powerful shaking of the steering wheel and front wheels after a driver hits road bumps at speed," affecting 2005-2010 model year Jeep Wranglers. The news report says NHTSA has received over 600 complaints about wobbling and vibrating in Jeep vehicles since 1995, "mostly Wranglers."
The two members of Congress describe the problem as "a powerful shaking of the steering wheel and front wheels after a driver hits road bumps at speed," affecting 2005-2010 model year Jeep Wranglers. The news report says NHTSA has received over 600 complaints about wobbling and vibrating in Jeep vehicles since 1995, "mostly Wranglers."
Last edited by JK-Tex; 03-20-2012 at 05:41 PM.
03-21-2012, 08:02 AM
#6
JK Super Freak
Every solid front axles vehicle can develop death wobble, hell even IFS can, I have got into peoples cars that have crazy vibes and the owner is oblivious until a tie rod etc or a wheel falls off.
03-21-2012, 08:05 AM
#7
JK Super Freak
Thread Starter
I am about as anti-big government as you can get, but I'm glad the feds are looking into this. DW isn't caused by having a solid front axle. It can be caused by lifting, but that's not Chrysler's fault.
However, stock JK DW is caused by a factory defect that Chrysler refuses to address (see planman's post above). Consumer pressure has done nothing. The fact that DW could be easily fixed from the factory (by changing out a few goddamn bolts) has done nothing. Chrysler has stuck its head in the sand on this issue. Maybe this will finally force them to confront reality.
Why all the hate for the NHTSA on this?
However, stock JK DW is caused by a factory defect that Chrysler refuses to address (see planman's post above). Consumer pressure has done nothing. The fact that DW could be easily fixed from the factory (by changing out a few goddamn bolts) has done nothing. Chrysler has stuck its head in the sand on this issue. Maybe this will finally force them to confront reality.
Why all the hate for the NHTSA on this?
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03-21-2012, 08:21 AM
#8
JK Super Freak
I am about as anti-big government as you can get, but I'm glad the feds are looking into this. DW isn't caused by having a solid front axle. It can be caused by lifting, but that's not Chrysler's fault.
However, stock JK DW is caused by a factory defect that Chrysler refuses to address (see planman's post above). Consumer pressure has done nothing. The fact that DW could be easily fixed from the factory (by changing out a few goddamn bolts) has done nothing. Chrysler has stuck its head in the sand on this issue. Maybe this will finally force them to confront reality.
Why all the hate for the NHTSA on this?
However, stock JK DW is caused by a factory defect that Chrysler refuses to address (see planman's post above). Consumer pressure has done nothing. The fact that DW could be easily fixed from the factory (by changing out a few goddamn bolts) has done nothing. Chrysler has stuck its head in the sand on this issue. Maybe this will finally force them to confront reality.
Why all the hate for the NHTSA on this?
03-21-2012, 08:26 AM
#9
JK Freak
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Originally Posted by planman
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.
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.
03-21-2012, 09:24 AM
#10
JK Super Freak
Thread Starter
I'm not saying that DW can't be caused by stuff wearing out. I can be and it is. But the undersized factory bolts cause premature wear, particularly in the front track bar bolt holes, which causes premature DW. It is a complete mystery as to why Jeep doesn't just use properly sized bolts.
