Death Wobble - Page 4 - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > JK Wrangler Technical Forum > Death Wobble

Poison spyder items @ oconee off road 706 534 9955Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineThe Solution to Radius Arm Bind - Meet Lock-N-Load

Reply
Unread 10-12-2011, 01:21 PM   #46
jstrubberg
Registered User
2009 JK Wrangler 
 
Join Date: Jul 2010
Location: Missouri
Posts: 2,124
It isn't the damper that causes DW. A good enough damper will cover up DW until it fails. The dealer hasn't touched the cause of the problem yet.

jstrubberg is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 02:14 PM   #47
jwmbishop
Registered User
2011 JK Wrangler 
 
Join Date: May 2011
Location: corsicana, tx
Posts: 3,428
Quote:
Originally Posted by Avernar View Post
Who said anything about banning solid axle front ends?
Indirectly - every poster (see posts 1, 4 and 13) who says "call' or "join petition" or "complain". Just as the corvair went away quitely - so will live axle as enough people whine because there simply is no cure for "death wobble" (and probably more than half of the whiners complaining aren't even feeling it but just the regulars tremors and oscillations live axle creates), you fix as it goes or you don't have. No in between..... we whined about health care so they fixed it, enough complaints and the NHTSA will fix it for us. By limiting the application to industrial commercial only and out of the hands of the avg joe doing the complaining...
A tourniquet, ambulance and ICU is not required for a papercut any more than a complaint to the HHTSA is warranted from front end shimmies, shakes or wobbles - even if in the magnitude of a Death Wobble.
__________________
J Wm Bishop EA, ASADE
Money cant buy happiness. But it can buy Jeep parts. Same thing.
jwmbishop is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 02:30 PM   #48
Avernar
Registered User
2010 JK Wrangler 
 
Join Date: Sep 2009
Location: Mississauga, ON
Posts: 192
Quote:
Originally Posted by jwmbishop View Post
because there simply is no cure for "death wobble"
Deja-vu. I just had this same conversation on another forum. We're not asking for a 100% cure for DW. Since it's very rare on a stock vehicle there's a couple of things they can do to practically eliminate it.

The first thing is to replace that track bar bolt with the correct sized bolt.

The second thing is to properly train their dealerships. This would involve them adding torquing the bolts to the oil change procedure. And when someone comes in with DW they should know it's not the steering stabilizer.
Avernar is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 03:02 PM   #49
jwmbishop
Registered User
2011 JK Wrangler 
 
Join Date: May 2011
Location: corsicana, tx
Posts: 3,428
hmmmm sounds good but:

Quote:
Originally Posted by Avernar View Post
Since it's very rare on a stock vehicle the design of the front suspension as built including, geometric angles, tire tread width unsprung weight and other contributory factors, must be close enough to reduce the reciprocal bump steer to a point where the dampner easily controls it there's a couple of things they can do to practically eliminate it. Seems THEY already did and WE undo it by adding our aftermarket mods then expect "them" to

to properly train their dealerships on the correct installation, adjustment and maintenance of every single modified part (or combinations therein available..
You mean that bolt is incorrect for the stock setup? how is it that so many unmodified vehicles go with no problems?

It makes sense that we want them to build the jeep so that everything works when we put on our 600 lb bumpers, 14 inch wide tires and 6 inch lift kits. Who cares that if they DID make it so convenient to the minority of buyers the ones who have no responsibilty to take for modifications (the majority of buyers) would have the crappy end of the deal.
__________________
J Wm Bishop EA, ASADE
Money cant buy happiness. But it can buy Jeep parts. Same thing.
jwmbishop is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 03:10 PM   #50
jstrubberg
Registered User
2009 JK Wrangler 
 
Join Date: Jul 2010
Location: Missouri
Posts: 2,124
The bolt is incorrect for the stock setup, and that's one of the two thigns in these rants that I agree should change. There's no reason at all to have that bolt be smaller than the hole it fits through. It's just asking for a problem to develop.

The other thing that ought to be done is that dealers need to be made aware of how to FIX death wobble, not cover it up. They're going to get someone killed doing things the way they are.
jstrubberg is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 03:29 PM   #51
Avernar
Registered User
2010 JK Wrangler 
 
Join Date: Sep 2009
Location: Mississauga, ON
Posts: 192
Quote:
Originally Posted by jwmbishop View Post
You mean that bolt is incorrect for the stock setup? how is it that so many unmodified vehicles go with no problems?
Yes. The bolt is slightly too small. As long as the bolt is torqued correctly it will keep it from moving. This is basically a band-aid for the wrong bolt size. If the dealer doesn't keep it torqued to spec a good bump can cause the bolt to move too much and start damaging the bushing on the track bar.

As for the red modification of my text above there's several things I don't agree with there:

First, it happened to me on a stock vehicle. I wouldn't complain if it was happened after I modified the suspension. When I said the dealers should be trained to fix DW, I mean on a STOCK setup.

Second, the steering stabilizer is not there to protect a badly engineered track bar joint. It's there to keep bumps from translating up to the steering wheel. On a properly designed solid axle front end a steering stabilizer is not necessary to prevent/hide DW.
Avernar is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 04:13 PM   #52
bluegrassguitar
Registered User
2011 WK 
 
Join Date: Oct 2010
Location: Woodruff
Posts: 235
My JKU is totally stock. I have had severe "death wobble" occur two times this month, to the point of nearly losing control. It's going into the shop this week and I will ask to be allowed under the Jeep with the mechanic to inspect the bolt size and to make sure the bolt is torqued correctly. I would really like to get this stopped before I lose control and kill myself or someone else.
bluegrassguitar is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 10:25 PM   #53
planman
Thanks to all Mod erators
 
planman's Avatar
2007 JK Wrangler 
 
Join Date: Sep 2004
Location: Billings, Montana
Posts: 1,361
Quote:
Originally Posted by jwmbishop View Post
because there simply is no cure for "death wobble"
It is very simple to diagnose and fix DW. It is simple to cure.

My write-up has been referenced here several times.

For those who are too lazy to click a link to go read it, I'll copy posts #1 and #2 here:

I'll start out by explaining that Chrysler decided to use a 14 mm trackbar bolt, with a trackbar bushing sleeve designed for a 9/16" bolt, and the trackbar bracket bolt holes are somewhere around 15-16 mm large. This is a sure recipe for DW if the trackbar bolts are not properly torqued and periodically re-torqued to 125 ft. lbs.


Because my DW posts are buried in other members' threads and in some PMs, here is a thread of its own.

I will also include info on non-DW shimmies and wobbles in the thread.

I will clean it up as I go, but it should be helpful nonetheless.


Death Wobble is no mystery.

It is caused by loose bolts, damaged components, or improper installation.

Look at the picture below and follow along:



First, the tie rod (green) has ends that attach to a knuckle on each side. As you could imagine, if either ends of the tie rod were broken or bad, that could be a culprit for a shimmy (not Death Wobble). A common place to damage the tie rod is on the driver's side at the adjusting sleeve (in the picture, just to the right of the red swaybar link). That sleeve (maybe not the correct term for it, but you can see what I am talking about) allows the width of the tie rod to be expanded or contracted. There are threads on that end that can be damaged, causing play on that driver's side and allow an up and down, or circular play movement. Again, this would cause a shimmy, not Death Wobble.

Next, look at the drag link (purple). On one end, it attaches to the pitman arm (lavender), that attaches to the steering gear box. On the other end, the drag link attaches to the passenger side knuckle. When you turn your steering wheel, a shaft turns that goes to the steering gear box. The steering gear box turns the pitman arm, and the pitman arm pushes or pulls the drag link, which pushes or pulls the knuckle. Your steering wheel is straitened by loosening the two nuts on the sleeve/turnbuckle on the drag link and rotating the sleeve/turnbuckle to lengthen or contract the length of the drag link. If either end of the drag link is damaged, this would cause a wobble or shimmy, but not Death Wobble.

Next, look at the trackbar (aqua). It attaches to a bracket on the frame on the driver's side and to the axle on the passenger side. The purpose of the trackbar is to center the axle on the frame. With the axle centered on the frame, it provides some resistance to the steering system to allow you to turn. If there was no trackbar and you turned the steering, the whole front frame would shift. As a result, there is significant force applied to the trackbar in driving and steering.

Now, imagine that the bolts that hold the trackbar are loose in their bolt holes, or that the bolt holes are wallowed out (oval), or that the bushings at the trackbar ends are damaged, or that the bracket at the axle side has come loose because the weld has broken, or that the bushings are all twisted up because the rig has been lifted without the installer loosening the bolts and then retightened them at the new ride height. All these things would allow play in the front trackbar. When you steer or go around a corner, these loose or broken things would allow the axle to shake or slide side to side. If you hit a bump in the road, it could knock the trackbar towards the driver's side. Then, the rest of the suspension (springs, etc.) would try to bring the trackbar back to the passenger side. If you were going at any sort of speed, you could develop a kind of harmonic resonance as the axle more and more violently slide/rocked/shaked from side to side. It would feel like your whole front end was being voilently torn apart. You would have to bring your vehicle to a complete standstill to stop the harmonic resonance. This is Death Wobble.

Even one incident of violent Death Wobble related to the front trackbar can cause significant damage. The voilent harmonic resonance of the back and forth shaking is more than the trackbar bushings, bolt holes, and brackets are designed to handle. A severe Death Wobble occurance can crack or break the welds on the axle side trackbar bracket, or the bolt can wallow out the bolt hole in the bracket, or the bushing can be permanently damaged.

This is the most common source of Death Wobble because inexperienced installers either do not remove the bolt from the trackbar when they install a lift--leaving the bushing pinched in the bracket and bound up, or they do not properly torque the bolts after the lift has been installed with the tires on and the full weight of the vehicle on the ground at ride height, or (maybe the most common) they do not retorque the trackbar bolts after the first 50 miles, after every heavy wheeling trip, and at every oil change interval.

Next, look at the lower control arms (purple) and the upper control arms (light blue). In the picture, they are aftermarket arms with a heim joint on one end. However, the stock control arms have a rubber bushing at each end. When the control arms are properly torqued, the bushing is somewhat pinched in the mounting brackets on the axle and the frame. Sometimes, an installer will make the mistake of not loosening the bolts for the control arms when they install a lift. What happens sometimes is they really bind up the bushings because they are pinched/sandwiched at stock ride height, but then forced to the new lifted ride height. These bound up bushings can cause weird handling, bushing failure, and lead to Death Wobble. The proper way is to loosen the bolts, install the lift, reinstall the wheels so the suspension and jeep are at the new ride height, rock the vehicle/suspension back and forth and side to side, then re-torque the bolts to spec, then after 50 miles re-torque them to spec, then after every oil change or very heavy wheeling trip re-torque them to spec.


Improperly balanced tires, too much air in tires, bent wheels, improperly installed wheel spacers, bad tires (with separated plys), and poor alignment specs (caster, camber, and not enough toe-in) can cause wobbles and shimmies that lead to Death Wobble. However, these precipitate Death Wobble, but they are not the cause of Death Wobble.

Although not specifically identified in the picture, the ball joints that are at the top and bottom of each knuckle where it attaches to the axle C can go bad. Bad ball joints can cause shimmies, wobbles, but usually not full on Death Wobble.

Next, allthough not identified in the picture, the unit bearings can go bad and be a cause of shimmy and wobble, but not Death Wobble.

Hope this helps--assuming you read it all.

Death Wobble is no mystery.

The reason that the steering stabilizer masks it is that it can absorb some of the side to side voilent harmonics of a loose trackbar or damaged mounts. However, this masking is dangerous because it will not prevent the eventual failure of trackbar bracket welds and bolt holes from trackbar Death Wobble.




It is extremely important to immediately diagnose and fix Death Wobble.

Even one episode of DW can damage other components.

Multiple episodes of DW are almost guaranteed to damage other components.

Multiple episodes will often damage your:
  • ball joints
  • tie rod ends--including the adjusting sleeve end on the driver side
  • trackbar bushings
  • trackbar bracket bolt holes
  • steering sector shaft (where the pitman arm attaches to the steering box)
  • steering stabilizer
  • front lower control arm bracket bolt holes
  • unit bearings
  • trackbar bracket welds
  • drag link ends

Hellbound13 is an example of a member who with 5-6 episodes of trackbar related DW on a stock jeep ended up "chasing his tail" for many, many months. He ended up replacing almost everything in the above list--sometimes more than once.

Without repairing/replacing everything that was damaged at once, the remaining damaged components continued to cause DW problems, further damaging the remaining components.




This is Death Wobble (and the guy is extremely foolish for repeating it on purpose):

planman is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 10:25 PM   #54
planman
Thanks to all Mod erators
 
planman's Avatar
2007 JK Wrangler 
 
Join Date: Sep 2004
Location: Billings, Montana
Posts: 1,361
NEW, UPDATED DIAGNOSIS CHECKLIST

Assuming your tire psi is 28-30, your tires/wheels have been balanced and rotated to make sure the wobble doesn't move with the rotation, here would be my order:

  1. Remove the steering stabilizer.
  2. Have someone turn the engine on and turn slowly from full lock to full lock while I visually, manually (with my hands on the components), and auditorily inspect for any play in the tie rod ends, drag link ends, sector shaft, trackbar ends/bolts/brackets, and trackbar bracket welds.
  3. Then, do the same thing but with short, sharp, quick back and forth turns of the steering wheel between the 10 o'clock and 2 o'clock positions, instead of the slow, lock to lock approach.
  4. Then, I would remove the front trackbar to inspect the bolt holes for ovaling and inspect the trackbar bushings for separation or cracking with a long screw driver through the bolt sleeve and the trackbar in a vise to leverage against the bushing in all directions. If all is good, I would reinstall the trackbar with the tires on the ground at ride height to 125 lbs.
  5. Then, I would inspect the drag link end joints by using a large channel lock wrench that gave me enough leverage to check for up and down play in the drag link ends. There should not be any meaningful up and down play. If there is, the ends should be replaced, or a new drag link with heavy duty joints should be installed. After, I would check the torque of the drag link ends. Taller lifts magnify the problems of bad drag link ends.
  6. Then, I would inspect the tie rod ends with the channel lock wrench for up and down movement. There should be no meaningful up and down play. There should only be rotational movement in the joint end.
  7. Then, I would put the front axle on jack stands with the tires about 2" off the ground and check the front ball joints by using a long pry bar as a lever under the front tires to lift them up to inspect for up and down play in the lower ball joints. There shouldn't be more than maybe 1-2 mm.
  8. Then, I would use the prybar/lever against the frame and the top of the tire to inspect for lateral movement of the top ball joints. There shouldn't be any. If you have a lighter tire/wheel combo, you can do this by hand.
  9. Then, I would remove the front tires/wheels and remove the front tie rod--one knuckle at a time. Then with a large wrench or vice grips, I would inspect the end for side to side play. Then I would reinstall the end and torque to spec and repeat on the other side.
  10. Then, I would remove the brake calipers and brake disks to inspect the unitbearings for play.
  11. Then, I would reinstall the discs, brake calipers, and tires/wheels and set the axle back on the ground.
  12. Then, I would support but not lift the front axle with a floor jack and loosen the front lower control arm bolts. One at a time, I would drop the lower control arms to inspect the bolt holes and bushings (similar to with the trackbar), reinstall without torquing, and do the next one. Afterwards, remove the floor jack so the suspension is at ride height, vigorously rock the vehicle side to side and front and back, then torque to spec.
  13. Next, I would inspect the sector shaft that comes out of the steering box for cracking or twisting.
  14. Then, I would take a test drive without the steering stablizer to feel for any wobbles.
  15. Finally, I would reinstall the steering stablizer or spring $40 for a heavy duty steering stablizer.

If this front end inspection does not diagnose and/or solve it, then I would move to an alignment.
  1. I would use adjustable lower front control arms to set my caster spec between 4 and 5 degrees--with a cross caster that has less on the driver side than the passenger side. I would personally not do more or less, with a target around 4.5-4.7 degrees caster.
  2. If my camber is out of spec, but it is not due to failed ball joints, I would install offset ball joints to get my camber in spec.
  3. I would set my toe-in to spec on the machine--which is about a 1/8" toe-in.
  4. If my front to rear alignment is off, I would install rear lower adjustable control arms to fix this.

With all this, I highly doubt you do not find the source.

The last ditch thing if there is a non-DW, speed dependent range wobble, I would borrow a different set of wheels and tires to see if it changes, and I would try driving it with no front driveshaft to see if that changes anything.

Although it is always a good idea to inspect your axle shaft u-joints, they will not cause DW.

The most common sources of full on DW are:
  • Improperly torqued trackbar bolts
  • Damaged trackbar and control arm bushings because bolts were torqued on a car lift or while the vehicle was not at ride height with the tires on the ground. When you torque trackbar and control arm bolts, the bracket pinches the bolt sleeve in the bushing, as well as the bushing itself. If this is at a geometry other than actual ride height, the bushings are twisted/bound/pre-loaded, and they will eventually fail/separate/etc. If you have a flex joint end, this does not apply for that end.
  • Ovaled out trackbar bracket holes due to DW episodes from loose bolts.
planman is offline   Reply With Quote Quick reply to this message
Unread 10-12-2011, 11:28 PM   #55
JLC08JK
What was I thinking?
 
JLC08JK's Avatar
2008 JK Wrangler 
 
Join Date: Sep 2009
Location: Los Angeles, California
Posts: 5,789
Thanks for another great essay, Anthony
Just added to page #1, "will it rub" of the F.A.Q.
__________________
Jim
Jim's Jeep; THE OBSESSION LIVES ON!
Jim's JK D44 Rear Axle Build

99% of Your JK Questions will be Answered Here
JK F.A.Q./WILL IT RUB and Popular Threads

Protect Our Rights to Freedom and the Environment
Visit the EnviroBeat
JLC08JK is offline   Reply With Quote Quick reply to this message
Unread 10-13-2011, 10:36 AM   #56
jwmbishop
Registered User
2011 JK Wrangler 
 
Join Date: May 2011
Location: corsicana, tx
Posts: 3,428
Quote:
Originally Posted by planman View Post
It is very simple to diagnose and fix DW. It is simple to cure.
Death Wobble is no mystery.

It is caused by loose bolts, damaged components, or improper installation The only thing that can be added here is excessive wear....

not Death Wobble.

but not Death Wobble.

This is Death Wobble.

they are not the cause of Death Wobble.

shimmies, wobbles, but usually not full on Death Wobble.

shimmy and wobble, but not Death Wobble.

Death Wobble is no mystery.

The reason that the steering stabilizer masks it is that it can absorb some of the side to side voilent harmonics of a loose trackbar or damaged mounts. However, this masking is dangerous because it will not prevent the eventual failure of trackbar bracket welds and bolt holes from trackbar Death Wobble.

AWESOME write-up. the point I was trying to make (quite weakly compared to your eloquence) is that not all shimmies shakes and bumps are serious - quite normal in fact for live axle, thank yoi for the time and effort to demonstarte fully that concept. If people don't learn that fact - then EVERY instance of a shimmy shake or wobble is death wobble - and once the dintinguishing facets of DW are included every where - it no longer means anything!

In bther words - driving at 70 you hit a bump and it goes wobble wobble and stops! NOT DW! If the wobble does NOT stop until you seveerly slow the vehicle and totally relax the steering THEN you can say "I got death wobble"

Kinda like going to the doctor complaining of pneumonia when you have hay fever...
__________________
J Wm Bishop EA, ASADE
Money cant buy happiness. But it can buy Jeep parts. Same thing.
jwmbishop is offline   Reply With Quote Quick reply to this message
Unread 10-13-2011, 11:19 AM   #57
Avernar
Registered User
2010 JK Wrangler 
 
Join Date: Sep 2009
Location: Mississauga, ON
Posts: 192
Quote:
Originally Posted by jwmbishop View Post
If people don't learn that fact - then EVERY instance of a shimmy shake or wobble is death wobble
I fully agree with you there.

Quote:
Originally Posted by planman View Post
It would feel like your whole front end was being voilently torn apart. You would have to bring your vehicle to a complete standstill to stop the harmonic resonance. This is Death Wobble.
When people come into the forum thinking they have DW it doesn't take long for someone to ask if they had to come to a complete stop to halt the violent shaking. If not they are quickly told they don't have DW and just a run of the mill wobble or other vibration.
Avernar is offline   Reply With Quote Quick reply to this message
Unread 01-08-2012, 04:09 PM   #58
crltd
Registered User
 
Join Date: Jan 2012
Location: houston, texas
Posts: 1
who knows where i can get a hydrogen kit in houston texas to increase my mpg's? also what is the forecasted price?
thanks,
crltd
crltd is offline   Reply With Quote Quick reply to this message
Unread 01-08-2012, 07:09 PM   #59
JohnRodriguez
Registered User
1989 YJ Wrangler 
 
Join Date: Sep 2004
Location: Silver City, New Mexico
Posts: 400
my 08 has 83474 miles on it and yesterday I experience my first DW while I was crossing a set a RR tracks on a highway coming into the town i live at. the tracks are at about a 45 degree angle to the road and I usually hit it about 65mph. as soon as I hit it I new I had got DW. I jacket the front end up when I got home and checked everything, nothing was loose, so I took out the torque wrench and tightened the track arm bar to 125ft/lb + 1/4 turn more on axle and frame. took the jeep back out to the same tracks and hit it both directions, had no more DW. The only mod I have on front is dayster level puck thats been installed since day one and a JKS stearing stabelizer relocation kit with a tera flex shock installed about 3 month ago. I figure my track bar may have not been totally tight since then, but have had many trips across those particular RR trach since the install.
__________________
89 Wrangler, 2.5L TBI, D30 Truetrac 4.56 gear front, Super 35 4.56 gears rear, 31" BFG Mud's, 15x9" weld racing pro-stars XP's, 2.5" rancho and 1.25" shackels, superior axles. rear wilwood disc brakes

2008 wrangler x unlimited. Stone white. Motech 5.3L LS Chevy
JohnRodriguez is offline   Reply With Quote Quick reply to this message
Unread 02-03-2012, 07:01 PM   #60
williewvr
Registered User
2013 JK Wrangler 
 
Join Date: May 2011
Location: alice, texas
Posts: 400
Quote:
Originally Posted by Hellbound13 View Post
Well my friend who is a mechanic for a living can't figure it out and neither can I.
I work with a bunch of dicks but that doesn't make me a urologist. Being a mechanic is kind of like being a doctor, most are specialized into one field. Take it to a front end shop or a 4x4 shop.
williewvr is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
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






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.