Death Wobble Questions

[trailturd]

86 MJ 2.5 AX5 converted to 4wd with HP30 from a 96 xj. Added a Rusty's 3" lift when I did the conversion. Has had bad death wobble ever since. Replaced trackbar with a new stock length, since there was some play in the old one. Seemed to make it worse. Aligned with 6 degree caster, not sure if that is enough, considering getting adjustable lower control arms to get the caster in the 7-8* range. As well as eliminate the question of worn out LCA bushings. Running out of things to check and don't want to just throw money at it without having an idea of what's causing it. I got underneath it and had someone cycle the steering, tie rod ends all seemed fine. Steering box is tight to the frame, I swapped that out when I did the 4wd conversion as the stock box was non power steering. Front drive shaft has new u-joints also done during the 4wd swap. Ball joints and wheel bearings all checked out fine. Track bar moves a very small amount at the axle, but it looks and feels like it's just the bushing flexing slightly. What am I missing? I can drive 40-50 down a washboard rough gravel road and it's fine. Get on smooth pavement and hit an expansion joint wrong and all hell breaks loose. Any ideas? I'm at my wits end and about to light this thing on fire

[Pete M]

are you still running the 30 year old control arms?  or did the kit come with lowers?

[trailturd]

7 hours ago, Pete M said:

are you still running the 30 year old control arms?  or did the kit come with lowers?

The stock control arms

[Pete M]

I'd say that's your problem.   

[motownXJdad]

9 hours ago, trailturd said:

86 MJ 2.5 AX5 converted to 4wd with HP30 from a 96 xj. Added a Rusty's 3" lift when I did the conversion. Has had bad death wobble ever since. Replaced trackbar with a new stock length, since there was some play in the old one. Seemed to make it worse. Aligned with 6 degree caster, not sure if that is enough, considering getting adjustable lower control arms to get the caster in the 7-8* range. As well as eliminate the question of worn out LCA bushings. Running out of things to check and don't want to just throw money at it without having an idea of what's causing it. I got underneath it and had someone cycle the steering, tie rod ends all seemed fine. Steering box is tight to the frame, I swapped that out when I did the 4wd conversion as the stock box was non power steering. Front drive shaft has new u-joints also done during the 4wd swap. Ball joints and wheel bearings all checked out fine. Track bar moves a very small amount at the axle, but it looks and feels like it's just the bushing flexing slightly. What am I missing? I can drive 40-50 down a washboard rough gravel road and it's fine. Get on smooth pavement and hit an expansion joint wrong and all hell breaks loose. Any ideas? I'm at my wits end and about to light this thing on fire

First immediate suspects are non adjustable stock track bar, stock control arm bushings, then ball joints, then tie rods, and hub unit bearings. yes youll want 7-8°+ caster for 31" tires or larger. death wobble is usually caused by neglected maintenance items in the front suspension.

[75sv1]

    I had a serious bout of DW. Mine came down to a cracked frame, by the steering box. This was on a 4.5" lift and 32's. All new items. I did have Rusty's upper and lower control arms. I latter replaced them with JKS. The JKS did get damaged. I did run a Rusty's OTK trackbar. Which was OK for the level of the build. The bracket to the frame was being ripped off, due to the cracked frame. 

     On my next build, a 2" with 31's, I went with Core Stage 1 upper and lower control arms. Cost and quality, and level off the build. I also ended up with Stinky Fabs OTK trackbar brackets and trackbar brace. On both builds, I have WJ Big Brakes and crossover steering. 

      So, I'd agree with above, get a good trackbar. Get adjustable control arms. Or a lower one for a 3" lift and an upper adjustable. The upper is cheaper. Check into the WJ lower control arms. I think they are good for a 3"-3.5" lift. Then an upper adjustable control arm. 

      Also, DW will damage components. So, you need to check and replace. I'd probably replace the upper and lower ball joints. 

[Pete M]

WJ arms are the same length as stock and so will sometimes be long enough for a 3" lift.  it all depends on the individual truck and how much caster adjustment it has available. 

[75sv1]

Then I'd just go with CORE Stage 1's :

Core 4x4 Adjustable Control Arms Tier 1 Front Set Fits Jeep TJ-LJ-ZJ-XJ-MJ | eBay

 

CORE or Kevins Offroad trackbar. $240. 

[motownXJdad]

14 hours ago, 75sv1 said:

Then I'd just go with CORE Stage 1's :

Core 4x4 Adjustable Control Arms Tier 1 Front Set Fits Jeep TJ-LJ-ZJ-XJ-MJ | eBay

 

CORE or Kevins Offroad trackbar. $240. 

I'm running Core4x4 short arms on my XJ, super beefy, and awesome weld quality👍

[75sv1]

I did look at the cost of the fixed Rusty's control arms. More than the Core Adjustable. Also, the OP might think about welding on a washer at the trackbar location. On a 12mm, I am trying to use a 3/8 grade 8. I will have to open or enlarge the hole.

[trailturd]

Just wanted to give everyone a update. I replaced the track bar with a double shear adjustable one and centered the axle. I replaced the stock lca with adjustable ones with rubber bushings and set them at 16.09”, replaced the steering stabilizer, and I noticed the motor mounts were trashed so replaced those too. Jeep drives great now, just wish I would’ve done all of that right from the start. 

[Pete M]

excellent!     thanks for the update   

[motownXJdad]

On 10/3/2022 at 6:37 PM, trailturd said:

Just wanted to give everyone a update. I replaced the track bar with a double shear adjustable one and centered the axle. I replaced the stock lca with adjustable ones with rubber bushings and set them at 16.09”, replaced the steering stabilizer, and I noticed the motor mounts were trashed so replaced those too. Jeep drives great now, just wish I would’ve done all of that right from the start. 

feels good to get a victory don't it? nice work!