Diagnosing Death Wobble and Fixing Non-DW Shimmies and Wobbles - Page 10 - JeepForum.com
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Unread 11-27-2011, 08:51 AM   #136
VoodooTacos
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Location: North Kingstown, RI
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Replaced the drag link and did a quick test drive last night with the stabilizer attached. Seemed like an improvement, but only gave it about 15-20 minutes of driving. Today took it out for about 25minutes without the stabilizer, and it felt improved until I hit a patch of road that sent me into a wobble that required me to slow from 50 to 10mph to get out of it. Test drive was over at that point and I put the stabilizer back on. I'll give it some more road test time today when I drive back from RI to Northern VA, NY roads are where it normally wobbles out even with the stabilizer on.

At this point I've verified (to the best of my limited ability):
  • Front and Rear Trackbars and bolt holes are healthy, have good bushings and torqued properly.
  • Front LCAs are healthy, have good bushings and are torqued properly.
  • Lower Ball Joints do not have vertical play.
  • Top Ball Joints do not have sideways play.
  • Tie Rod does not have side to side or up and down play.
  • Drag link ends required replacement - New Drag Link does not have side to side or up and down play.
  • Tires are rotated, all inflated to 30psi, treads are healthy.

I am working with a 4" TF lift in front, 3.25" effective rear (2.5" TF coils in the back with a .75" spacer). I ended up with this setup because after having seen my front stock coils lose 1.25" with the new bumper + winch, I assumed I'd lose similar with new coils. Apparently TF coils don't give as much as I figured they would. As such I bought the spacer in case I had to level out, and turned out I did.

Though it happens infrequently, and usually a little breaking (reduction in speed of only about 10-15mph) will snap us out of it, the missus is mostly traumatized by the wobble and I'm thoroughly annoyed with it. As it's our only vehicle right now, she uses it as a DD (route 66 in VA - horrible roads) and I'm uncomfortable making her deal with my inability to rectify this problem. At this point I'm considering returning to the RC BB 2.5" for stability and that'd be at a waste of about $800+ if I reverted, which would suck royally. My ultimate goal is a 35" setup on 3-4" suspension. The plan was that until I can afford the 35's and all the required regearing and new hardware that goes with it, that I would do the suspension and would finish off my stock 32" Sahara tires while I save up. Stock tires are still in good shape.

With that backstory in mind, I see four possible courses of action next.
  1. Have a mechanic reinspect all components
  2. As a short term fix that will accomdate future 35" needs - Upgrade to longer LCAs - Will this make a difference?
  3. Add a high-steer kit to help some of the geometry issues and lessen the effects of bumpsteer (ideally lessening the threat of a wobble).
  4. Wait out until I can afford a complete 35" setup and keep using my goofy 4" lift on 32's setup.

I welcome any thoughts or follow up questions you have. Thanks very much.

Relevant Equipment List:
TF 4" Coils (Front) - TF 2.5" Coil with .75" spacer (Rear)
Bilstein 5100's
JKS Adjustable Track Bar - no bracket (Front)
Stock Track bar with relocation bracket (Rear)
Stock 32" Sahara tires
Original Ball Joints, Tie Rod
Replaced Mopar Draglink (both ends)

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Unread 11-27-2011, 10:30 AM   #137
VoodooTacos
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Just inspected the toe-in too for giggles, found it to be 3/16". Set it to 1/16", we'll see if that changes anything - Read that toe-in can have bearing on wobbles. Had it aligned after the lift went in, about a month or two ago. The reading from the shop stated 29 degrees, no idea what that translates to in inches.
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Unread 11-27-2011, 07:29 PM   #138
planman
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Quote:
Originally Posted by VoodooTacos View Post
  1. Have a mechanic reinspect all components
  2. As a short term fix that will accomdate future 35" needs - Upgrade to longer LCAs - Will this make a difference?
  3. Add a high-steer kit to help some of the geometry issues and lessen the effects of bumpsteer (ideally lessening the threat of a wobble).
  4. Wait out until I can afford a complete 35" setup and keep using my goofy 4" lift on 32's setup.

I welcome any thoughts or follow up questions you have. Thanks very much.

Relevant Equipment List:
TF 4" Coils (Front) - TF 2.5" Coil with .75" spacer (Rear)
Bilstein 5100's
JKS Adjustable Track Bar - no bracket (Front)
Stock Track bar with relocation bracket (Rear)
Stock 32" Sahara tires
Original Ball Joints, Tie Rod
Replaced Mopar Draglink (both ends)
With 4" of lift on stock arms, you have too little caster. This will contribute to wandering and shimmy/wobbles. So yes, front lower adjustable control arms will make a big difference.

With 4" of lift, you will have unfavorable steering characteristics similar to bumpsteer without some sort of steering correction. So, a drag link flip kit combined with an axle side trackbar relocation bracket will make a big difference in handling.

All this combined with small, skinny tires will aggravate things.

If you do the labor, it might be worth it to spend a weekend and go back to a short lift until you can afford to do the steering, front lower control arms, tires/wheels, etc., all at once.
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Unread 11-27-2011, 09:20 PM   #139
DrHolliday
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Quote:
Originally Posted by VoodooTacos View Post
Just inspected the toe-in too for giggles, found it to be 3/16". Set it to 1/16", we'll see if that changes anything - Read that toe-in can have bearing on wobbles. Had it aligned after the lift went in, about a month or two ago. The reading from the shop stated 29 degrees, no idea what that translates to in inches.
Adjustable lower control arms would make a huge difference. My 3.5" lift came out to almost 6" in front. My kit came with UCA's and LCA's even setting them to the specs in the instructions had me at .5* of caster IIRC. It was too hard to drive on the highway, no wobbles, but would wonder around everywhere (ruts in roads from studded tires).

Had it aligned and got 5* of caster back, drives like stock.

With stock arms and that much lift you could even have negative caster, ie, big problems.
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Unread 11-28-2011, 12:10 AM   #140
VoodooTacos
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Thanks very much for the feedback Planman and Doc.

Just completed my RI->VA trek, results were more favorable, though I could've just gotten lucky. Having done that run ~4 times since I put the 4" in, typically I'll experience 1-2 episodes wobble that will require some level of braking (15-20mph reduction in speed). Had none of that tonight, a couple mild shimmies at worst, again maybe I just got lucky (NYC certainly hasn't paved the roads since my previous trips however).

I had the alignment done just after the 4" lift was put in, I'll have to pull out of the specs tomorrow to verify. I'm still novice in alignments, only did my first steering wheel alignment and toe-in setting today. I have yet to learn the ramifications of and what makes up caster/camber etc...

I will be doing all the labor myself - what fun would it be otherwise? So my follow up question is: assume I get adjustable LCAs, and a drag link flip / trackbar relocation kit - in your estimation, should I be alright with that until I can afford the new feet? Understand doing it all at once is ideal from a safety and performance standpoint, but from a financial standpoint, that's hard to do (I'm broke!).

If not, I'll suck up my pride and revert back to the stock configuration in the meantime.

Thanks again.
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Unread 11-28-2011, 03:14 PM   #141
planman
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You should be fine waiting on the 35s as long as your tires are not too worn and you do not have too much toe-in.
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Unread 12-09-2011, 12:56 PM   #142
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Here is a video of a stock 14mm trackbar bolt in a stock trackbar bracket with a 9/16" hole.

This is why it is important to remove the trackbar to inspect the bracket holes for ovaling.

This is why it is a good idea to replace the stock bolts with 9/16" grade 8 bolts.

This is why it is important to re-torque the trackbar bolts at each oil change interval and after every major offroading trip.

Because dealers rarely remove the trackbar to inspect the bolt holes and replace the stock hardware with 9/16" bolts, they miss the most common source of DW.

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Unread 12-09-2011, 02:32 PM   #143
fishgutz
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After doing everything including the bolt and all the torquing, I still had shimmy, plus a while jeep vibration above 73.
Then the RK dude asked if I has steel or alloy wheels. Steel I replied. That was when I found out that steel wheels are more prone to manufacturing defects that can bew more noticeable with big meat than 32" or smaller.
The new alloy wheels did the trick.
Ran my JK for 800 miles each way at speeds running 75 to 80 mph. Shweet! Nice and smooth.
Never buying steel wheels again.
Anyone want a set of 5 Unique Series 297 black steel wheels cheap?
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Unread 12-09-2011, 05:19 PM   #144
planman
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Quote:
Originally Posted by fishgutz
After doing everything including the bolt and all the torquing, I still had shimmy, plus a while jeep vibration above 73.
Then the RK dude asked if I has steel or alloy wheels. Steel I replied. That was when I found out that steel wheels are more prone to manufacturing defects that can bew more noticeable with big meat than 32" or smaller.
The new alloy wheels did the trick.
Ran my JK for 800 miles each way at speeds running 75 to 80 mph. Shweet! Nice and smooth.
Never buying steel wheels again.
Anyone want a set of 5 Unique Series 297 black steel wheels cheap?
It can also be a problem with aluminum wheels.

This is why it is important to have your tire shop run your new wheels on their balancer to make sure they are very close or completely true prior to mounting tires on them.

After tires have been mounted on the wheels, they can't be returned.

What you should do is have your shop run the old steel wheels on their balancer to see which ones are bad.

You can sell the bad ones for use with spares or on trail rigs.

The ones that aren't too bad can be balanced sufficiently for most people, and you can get more $ out of them.

The shop might do it for free if you take them donuts or pizza.
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Unread 12-09-2011, 06:27 PM   #145
fishgutz
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Quote:
Originally Posted by planman

It can also be a problem with aluminum wheels.

This is why it is important to have your tire shop run your new wheels on their balancer to make sure they are very close or completely true prior to mounting tires on them.

After tires have been mounted on the wheels, they can't be returned.

What you should do is have your shop run the old steel wheels on their balancer to see which ones are bad.

You can sell the bad ones for use with spares or on trail rigs.

The ones that aren't too bad can be balanced sufficiently for most people, and you can get more $ out of them.

The shop might do it for free if you take them donuts or pizza.
In my case, it was the bolt pattern was offset just enough to mess it up. The wheels were true and on center at the hub. But the bolt pattern was not centered on the hub.
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Unread 12-09-2011, 09:52 PM   #146
planman
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That sucks. They should do a refund or at least replace them with that kind of defect.
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Unread 12-10-2011, 06:09 AM   #147
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Quote:
Originally Posted by planman View Post
Here is a video of a stock 14mm trackbar bolt in a stock trackbar bracket with a 9/16" hole.

This is why it is important to remove the trackbar to inspect the bracket holes for ovaling.

This is why it is a good idea to replace the stock bolts with 9/16" grade 8 bolts.

This is why it is important to re-torque the trackbar bolts at each oil change interval and after every major offroading trip.

Because dealers rarely remove the trackbar to inspect the bolt holes and replace the stock hardware with 9/16" bolts, they miss the most common source of DW.

YouTube - Death Wobble
--- Thanks for posting this.
I'm just about to put my new one on. I'll also need to weld a tab on the new 9/16th nut to replace the 14mm tabed one (to fit it inside the bracket)
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Unread 12-11-2011, 12:09 AM   #148
planman
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Originally Posted by RacerX View Post
--- Thanks for posting this.
I'm just about to put my new one on. I'll also need to weld a tab on the new 9/16th nut to replace the 14mm tabed one (to fit it inside the bracket)
You won't if you have a JK.

The first video is about changing the stock 14 mm bolts out for 9/16" grade 8 bolts.

The second video includes tips on performing a DIY toe-in alignment.


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Unread 12-11-2011, 01:53 AM   #149
RacerX
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Quote:
Originally Posted by planman View Post
You won't if you have a JK.

The first video is about changing the stock 14 mm bolts out for 9/16" grade 8 bolts.

The second video includes tips on performing a DIY toe-in alignment.
JK toe-in alignment tips - YouTube[/url]
Thanks for the vids, However I have a Cherokee, so short of adding a bracket, or cutting into the axle...
You don't think weldint the nut will soften it, do ya? - I'll just remember to keep a bucket of water near

I'd really like to design/build a stronger, greasable fitting/bracket for the axle side
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4-wheeling is about going where others can't won't or don't think it's safe.
Freedom. Exploring the wilderness, or nature, whatever... - NOT paying to go on someone's roller-coaster ride, or go-cart track!
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Unread 12-11-2011, 07:45 AM   #150
VoodooTacos
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As follow up to your advice, I put in TF adjustable from LCAs in yesterday (22 7/8" Driver, 23" Pass), which took me from about 2.8 Degrees Caster to 5-5.5 Degrees Caster, took it out in search of some local beat up roadways and it felt great. So for the archives, to fix the wobble I experienced as a result of installing 4" coils and shocks I did the following (whether it actually contributed to the fix or not may be subject):

Problem Started:
Install JKS Adj Front Track Bar
Balanced Tires
Had a Shop Alignment (wouldn't do it again - since learned how to do my own)
Problem Persisted
Ran through Planman's checklist (all sans the brake drum/caliper step).
Discovered vertical play in my drag link (both ends) and replaced with a MOPAR part.
Problem Persisted but seemed slightly improved.
Fixed my toe-in - despite the above alignment, I found that my toe was 3/16", I took it down to 1/16"
Problem dramatically went away. Still experienced a slight but very reduced shimmy on the worst bumps.
Installed Front Lower Control Arms (fixing Caster)
So far no problems! (~100 miles road test)
Crossing my fingers, but already I've noticed that I'm regaining confidence in driving. I found that I was flinching when I came to certain types of bumps expecting that on the other side of it I'd be wobbling, but felt nothing but a stable response. Now to figure out how to get the missus to respond in a stable fashion all of the time too....

Again, thanks to DrHolliday and Planman for the help, and to Planman for all the work involved in this thread. It is resources like this that allow and encourage me to continue experimenting and learning, and allows me to enjoy my Jeep as much as I do. Definitely appreciate the effort.
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