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Diagnosing Death Wobble and Fixing Non-DW Shimmies and Wobbles

158K views 217 replies 72 participants last post by  TheSecretSavage  
#1 · (Edited)
The Inspection Checklist is in Post #5 of this thread.

Most people would benefit from watching these two videos. The videos are kind of long at 18-19 minutes each. Hopefully, they are thorough enough to help.

PLANMAN explains Death Wobble Diagnosis and Inspection Jeep JK Wrangler Part 1 - YouTube
Part 2, PLANMAN explains Death Wobble Diagnosis and Inspection Jeep JK Wrangler - YouTube

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.

Stock JK bolt in stock trackbar bracket hole - YouTube

HITMONEY suggested I do a Death Wobble Write Up Dept. thread.

It is a good suggestion because my DW posts are buried in other members' threads and in some PMs.

So, here are some of my posts and PMs regarding DW.

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:

Image


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):

Death Wobble - YouTube
 
#90 ·
i did go through the check list but i was just wondering in general as a fix all solution if that would work. like a nuclear bomb on death wobble :devil:

also, correct me if i'm wrong but if i fix any and all causes of full on death wobble, would tires be able to cause any sort of serious wobble? i ask because i've never been able to get my mtr/k satisfactorily balanced and after finally fixing the causes of death wobble i don't want my tires to ruin it all for me. so is this a viable concern or should i be good to go even with my sh!tty tires?
 
#91 ·
Well, while you are switching everything out, you should be able to re-do the inspection checklist--including checking bracket bolt holes for ovaling.

I was just suggesting that you may not need to buy all that stuff and that you may be able to allocate funds torwards other upgrades or repairs. You don't really need the rear control arms with a 2.5" rear lift.

For example, what if your steering box is bad?

Or, what if your problems are wallowed out trackbar bracket bolt holes? The new bolts alone will not fix this.

If you still have 2.5" front springs and 1.75" coil spacers, for a total 4.25" front lift, you want a drag link flip kit and front extended bumpstops that are at least 3" long. So, that fits your list well.

However, if your DW has continued over the last year, you may have damaged more components--i.e. the front upper axle side control arm bushings.
 
#96 ·
Figured I'd share this here...

After years of dealing with steering issues I finally got my JK to drive better then stock!!!

I replaced all my steering components and my knuckles. I balanced my tires 10X. I did everything!!! And I still had bad bump steer, a wobble at 50-55 mph and a wobble at 70+ mph.

I had the Teraflex trackbar drop bracket on the JK since I first bought it. Recently I welded the bracket on the kit to make sure it doesn't shake. Sill didn't help.

A few days ago I ditched the TF bracket and installed a Synergy passenger side track bar mount that raised the trackbar. ALL my issues went away. The JK drives better then my stock Grand Cherokee!!

This is the Synergy bracket...

Image


This is my setup before the Synergy Bracket. Observe the positioning of the trackbar and drag link.

Image


This is how it is now. Notice that the drag link and trackbar are at the same angle and same height from ground. I took off the TF drop bracket and put the driver side trackbar into the stock position.

Image


I never thought this would solve my issues.... but it did!
 
#98 ·
DW

I have or had the death wobble on my 2011 jk (10,00 miles) after i put the 2.5 inch leveling kit on it. I found slop in the pan hard bar and was able to fit a 5/8 bolt in it at one end. Anyhow, if you do the 2.5 lift and nothing else you shouldnt have changed the caster by more than a degree or so, when I get my 33's will this one degree be acceptable or do I really need to get the adjusting bolts?
 
#99 ·
You should be fine with stock control arms and a 2.5" lift.

If you want to improve handling, you would buy adjustable front lower control arms. Avoid cambolts if at all possible.


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#102 ·
which ones would you recommend, is it really worth it....will 1-2 degrees (my tiny lift in mind) really make a noticeable difference?
At 2.5" lift, it isn't really necessary.

I like the Currie control arms with flex joints at both ends. However, I've run Rock Krawler and Teraflex arms and been very happy with them as well.


Not sure why this is not a sticky or even in the write-up Library!

Thanks for the info. I replaced the 14MM bolts with 9/16 and retorqued everything down DW gone!
This thread is the 1st one listed under "Suspension" in the Write-Up Library.
 
#103 ·
whats the thoughts on overtorquing for the track bar bolts?


i went and bought some of the recommended size and came home to install and it appears that the factory bolts were the correct size in my '08, or the previous owner had changed them out. they look factory though as the axle side had the flag on the nut and they were the same exact looking bolts as the rest that i had to work with when i put the lift on my jeep.

140lbs just doesnt seem like enough torque. i went for a little test drive and my shimmy over bumps was still there. :(
 
#104 ·
the correct size to fix factory problem (9/16") won't fit the factory flag nut. I would change them. 125ft. lbs. is factory torque .
 
#110 ·
Another problem. After getting a teraflex levelling kit and 1.75" coil spacers I have the dw coming back. The axle side trackbar bracket has the holes ovaled a little bit where there is play. Is there a bolt on option for this or do I need to have a new bracket welded on?

ps. I have the F911 hardware kit that was installed a couple months back where the larger bolts fixed the dw initially.
 
#111 ·
The fix for ovaled holes is to weld washers over the front and back of the holes.

You also need to inspect the bracket welds for cracks if you haven't already when performing the inspection checklist on the first page of this thread.


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#116 ·
Questions...Just yesterday I experienced my first DW ever after running the jeep for nearly three years. I have recently bought all of the grade 8 hardware and purchased a JKS track bar/Steering Stab relocation bracket and have pulled off the stabilizer running without the stabilizer until I can get the bracket welded on.

Should running without a steering stabilizer cause DW????? I would think not but can anyone chime in?

I know the obvious DW culprits, TRE and track bars but what about the the ball joints...what's the best way to check them?

I plan on hopefully working on the Jeep this week doing the bracket and putting in the new grade 8 hardware any help would be appreciated...also any other item I should check.

Sorry for all of the questions going in all different directions...not yet awake:)
 
#118 ·
Does caster has anything to do with DW?
I am planing to replace my CA with the Metalcloack kit in order to correct caster cause my stock CA bushings weared out and my front axle is pushed foward and the rear axle is pushed backward.
Thanks
 
#119 ·
Low caster results in wandering and some wobbles. Too much caster results in wobbles. Neither result in full on, violent Death Wobble.

Worn bushings can result in Death Wobble when combined with low caster.


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#121 · (Edited)
I've had good results with Currie, Teraflex, Rock Krawler and Trailmaster (long arms).

TnT, Rokmen, JKS, and others have good components.

I wouldn't run Rough Country, SkyJacker, or other lower tier quality arms.



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#125 ·
I've had good results with Currie, Teraflex, Rock Krawler and Trailmaster (long arms).

TnT, Rokmen, JKS, and others have good components.

I wouldn't run Rough Country, SkyJacker, or other lower tier quality arms.

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DW gone! Replaced rubbers an above check-list done! Feathered BFG rubbers = huge PITA!
Next on the menu adjustable CA!
Thanks again Planman for your help! Thumbs Up and at least 1tone of bear!!!!
:gluging:
 
#122 ·
Here is a short description of my set up

Poly High Steer Kit
Poly Track Bar
Poly Tie Rod
Poly Drag Link
Poly Frame Side Track Bar Brace
Poly Axle Side Track Bar Brace
Poly HD Ball Joints
Poly Lower adjustable Control Arms
Currie Upper Adjustable Control Arms
Fox Steering Stabilizer

I am right at 5 degrees caster and 1/4 inch toe in. I am getting a shimmy between 30 and 40 MPH and it had turned into full blown DW. I have had DW before and resolved the issue with the above mentioned parts. Yesterday, I got my GoPro out and shot a video of the driver and passenger side. The is a clip of the passenger side. On the drivers side video there was absolutely no movement in the track bar. In this video is look like to me my movement is coming from the ball joint and knuckle area. Any help and thoughts would be appreciated.

http://s760.photobucket.com/albums/xx245/jgarner74/Jeep Stuff/?action=view&current=GOPR0016.mp4
 
#123 ·
FYI. The shaking begins about 1:45 into the video.
 
#124 ·
1/4" toe-in is way too much. It will feather your tires--which by themselves would cause shimmies if feathered.

I'm on my phone. So, I don't know if your video will load. I'll try it.

Have you watched my 2 new YouTube videos on DW?


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#127 ·
Planman, Yes I have watched the two videos several times. This is not my first go around with DW, hence all the Poly stuff up front.

I was under the impression with a large tire like a 39.5 that I am running it could handle the 1/4 toe in. If you get a chance please watch the video. I will try a different toe setting this weekend and see if that helps.
 
#126 · (Edited)
Regarding toe, I recently replaced tie rod ends because my boots were torn, but the ends were not worn. I have a solid rock krawker bar so toe adjustments are done by screwing in or out the ends. The jeep was driving PERFECTLY for months before I replaced the ends, then immediately afterwards I was getting the onset of dw which was induced by bumps. My toe was set at 1/16" by my mechanic friend and me.

Long story short, the only way I was able to get rid of the dw was to set the toe OUT slightly. Remember, I can only adjust by one turn of the end at a time. So now I'm toe'd out slightly, about 1/16-1/8" and the jk is driving better.

Oh, and all other systems are a go, bolts torqued, ball joints good, tires balanced, etc. the tires and worn though.

Go figure.
 
#129 ·
#130 ·
Sounds great. It hard to see but if you expand to full size you and see the movement in the knuckle. I am not a paying photobucket member so it will not load up in full HD like the GoPro records in.

I will tell you when this all started I was on a trail ride and took a very hard hit on the passenger front wheel climbing dry waterfall ledge. It was one of those where I was not over far enough to the left and hit another ledge that was there with that tire. Actually, when I hit it it made loud pop/crack and we all thought I broke something, but could never see anything.
 
#135 ·
DW issues once again!

Ok last winter I had my 07 JK with a RK 3.5 full flex lift tore down due to worn out ball joints and beefing up front axle housing and installing a high steer kit. Before I tore it down I was starting to get the DW and after replacing the drag link with a poly high steer, and a heavier duty Steering stablizer, and most important the ball joints. I got the jeep back on the road and I hardly ever get a chance to get this thing off road! The jeep was driving great after about 4 months I started getting a pop in the front end and found the problem and fixxed it, I thought. Had it tore down for about another couple of days, and after replacing 2 bolts that holds the wheel bearing in on the d/s. Still kept hearing a pop when I took off. checked everything and it was tight, so I FINALLY took the time and pulled into the shop and had one of my guys to get underneath when I creaped forward, and thats when we saw the the track bar on the axle side is working back and forth when the wheel is turned and then found a fresh wear mark on the p/s lower control arm. So this weekend going to take it back in and replace the track bar bolt and see if anything is ovaled out and go from there. Hopefully this will take care of my problem. But very good information.