Death Wobble after adjustable track bar replacement? suggestions for fix

[zeebo56]

I have a 2020 JLU sport S. I was on the freeway at around 70mph about a week ago and there was a bumpy section of the highway. The jeep started shaking like crazy and I thought the driver side wheel was going to pop off.

So I am not sure if the death wobble is related to having my Rancho front adjustable track bar installed or not. But I hadn't felt any significant bouncing or death wobble for 8k miles until I did the adjustable front track bar.

I had to extend the adjustable track bar out about .75" longer than stock to try to get my passenger wheel to stick out past the fender the same as the driver side. Maybe that is causing the problem?

My suspension consists of:

Rubicon take off springs and shocks
Mopar longer LCAs non adjustable
2.5" rough country spacer lift kit
35" milestar patagonia tires on Edge 17s
Rancho Rear adjustable track bar which was kept close to stock length

And recently in the past couple weeks the Rancho front adjustable track bar but extended a little over stock.

Drag link was adjusted to center the steering wheel and I did a slight alignment with the toe.

First 8k miles no issues with most of the other components until I did the front track bar a couple weeks ago. Also seems like in general the ride is a little bumpier. But the death wobble really freaked me out.

I don't think any other parts have failed. I was wondering if the steering stabilizer should be replaced at this time or is there something else you would suggest?

thanks

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[Sheepjeep]

check for any loose bolts on the steering and front suspension

also get someone in the driver seat and turn the wheel back and forth while you lay under it to see if anything could be loose or took much slop

 

[limeade]

When you installed and torqued the front track bar, was the Jeep on jack-stands or on it's wheels?

If it was on jack-stands, I'd loosen the two bolts and then re-torque with the Jeeps weight on the ground.

Also, what did you torque it to?

 

[Roky]

I have a 2020 JLU sport S. I was on the freeway at around 70mph about a week ago and there was a bumpy section of the highway. The jeep started shaking like crazy and I thought the driver side wheel was going to pop off.

So I am not sure if the death wobble is related to having my Rancho front adjustable track bar installed or not. But I hadn't felt any significant bouncing or death wobble for 8k miles until I did the adjustable front track bar.

I had to extend the adjustable track bar out about .75" longer than stock to try to get my passenger wheel to stick out past the fender the same as the driver side. Maybe that is causing the problem?

My suspension consists of:

Rubicon take off springs and shocks
Mopar longer LCAs non adjustable
2.5" rough country spacer lift kit
35" milestar patagonia tires on Edge 17s
Rancho Rear adjustable track bar which was kept close to stock length

And recently in the past couple weeks the Rancho front adjustable track bar but extended a little over stock.

Drag link was adjusted to center the steering wheel and I did a slight alignment with the toe.

First 8k miles no issues with most of the other components until I did the front track bar a couple weeks ago. Also seems like in general the ride is a little bumpier. But the death wobble really freaked me out.

I don't think any other parts have failed. I was wondering if the steering stabilizer should be replaced at this time or is there something else you would suggest?

thanks

After you check what mentioned above, I would get a pair of adjustable front lcas.
The Rubi takeoffs netted you at the very least 1” probably more, and with your spacer kit, you’re at least 3.5” of lift. Those Mopar arms aren’t long enough to give you enough caster. I’m not saying this caused your DW but it sure didn’t help it any, lol. It’s possible if you had this happen with more caster, it wouldn’t have been as severe.

 

[eck]

Same thing happened when I swapped my front track bar. I torqued everything down to spec (can't remember offhand) and had a fair bit of wobble. I chased the problem for a while and what ultimate fixed it was just tightening the track bar bolts some more. I basically just tigtened it up as much as I could get it by hand with a big ratchet.

 

[zeebo56]

check for any loose bolts on the steering and front suspension

also get someone in the driver seat and turn the wheel back and forth while you lay under it to see if anything could be loose or took much slop

Ill recheck the bolts but I usually torque everything down very well.

When I get someone around to check that I will. thanks

When you installed and torqued the front track bar, was the Jeep on jack-stands or on it's wheels?

If it was on jack-stands, I'd loosen the two bolts and then re-torque with the Jeeps weight on the ground.

Also, what did you torque it to?

I will double check the track bar but I made sure to torque it down a lot. I used a breaker bar and I actually have a tendency to overtorque things lol.

I did it with the jeep on the ground.

After you check what mentioned above, I would get a pair of adjustable front lcas.
The Rubi takeoffs netted you at the very least 1” probably more, and with your spacer kit, you’re at least 3.5” of lift. Those Mopar arms aren’t long enough to give you enough caster. I’m not saying this caused your DW but it sure didn’t help it any, lol. It’s possible if you had this happen with more caster, it wouldn’t have been as severe.

I will consider the adjustable LCAs. I hated taking off the stock ones, such a pain in the ass. Probably the hardest part of the suspension install that day I did it. I was exhausted when I got to them and they were torqued on so damn tight.

Same thing happened when I swapped my front track bar. I torqued everything down to spec (can't remember offhand) and had a fair bit of wobble. I chased the problem for a while and what ultimate fixed it was just tightening the track bar bolts some more. I basically just tigtened it up as much as I could get it by hand with a big ratchet.

I will retighten the track bar bolts and go from there.

thanks for the suggestions everyone.

no comments about the steering stabilizer maybe helping?

 

[limeade]

no comments about the steering stabilizer maybe helping?

A properly setup suspension and steering system don't really need a steering stabilizer. Take it off and see if it helps or makes it worse. IMHO a steering stabilizer is never the "cause" of death wobble. The VAST majority of times it originates with the front track bar or associated parts (elongated bolt holes, bad bushings, bad mounts, and using a stock TB to control the forces generated by larger/heavier tires and wheels).

 

[zeebo56]

A properly setup suspension and steering system don't really need a steering stabilizer. Take it off and see if it helps or makes it worse. IMHO a steering stabilizer is never the "cause" of death wobble. The VAST majority of times it originates with the front track bar or associated parts (elongated bolt holes, bad bushings, bad mounts, and using a stock TB to control the forces generated by larger/heavier tires and wheels).

Would not having the track bar at the proper length cause death wobble?

 

[Headbarcode]

A non centered axle wouldn't cause the wobble. Recheck the torque on the track bar bolts, including the adjuster jamb nut or pinch bolt (not sure which you have).

Also, you mentioned adjusting the toe. Was that done at the same time as the front track bar? If so, what did you adjust it to? Too much toe-in was the source of my wobble.

 

[limeade]

Would not having the track bar at the proper length cause death wobble?

No, not that I've ever seen.

I had a TJ that experience death wobble after installing a lift. I went cheap and didn't add an adjustable front track bar. I also had too much toe out (TJ steering setup is a slightly different than a JL and adding a suspension lift will cause the toe to change). I adjusted the toe and had no more death wobble, but had a shimmy at certain speeds. I added a Currie track bar and everything was tight and stable again. I discovered the axle mount for my track bar had wallowed out some (common on TJ's), which allowed the track bar bushing to move slightly.

On a JL, your drag link and tie rod are attached to the knuckles (passenger side for drag link and both for tie rod) but not attached to themselves (unlike on the TJ, where the drag link attaches to the tie rod). So it is possible for either the drag link and/or the tie rod to induce abnormal movement into one or both of the steering knuckles if one of the steering ends is bad. Combined with another problem (either in the track bar or control arms), this could culminate into death wobble.

If your track bar checks out, then I'd look at your steering ball joints.

 

[Halstem1]

Does anyone know if there is anything you can do to increase the torque on the track bar bolts? If I understand correct, torque settings are limited by the bolt itself and over-torquing could lead to snapping the bolt. Correct? Obviously I can't go to a larger bolt because of the TB bushing itself.

 

[limeade]

Does anyone know if there is anything you can do to increase the torque on the track bar bolts? If I understand correct, torque settings are limited by the bolt itself and over-torquing could lead to snapping the bolt. Correct? Obviously I can't go to a larger bolt because of the TB bushing itself.

Yes, the amount of torque is directly related to the fastener itself. The amount of torque needed is also related to the clamping force that part needs and the forces being influenced on that part.

Depending on the thickness of the sleeve in the track bar bushing, it is possible to drill the metal sleeve out slightly so a larger diameter bolt can be used. This was a trick a lot of people used for the TJ front track bar when the axle bracket got wallowed out. I did this in order to run a Grade 8 bolt that was slightly larger in diameter than the stock metric bolt. The Grade 8 bolt I used (forgot the size, maybe a 9/16"??) could be torqued higher than the stock bolt. I also drilled out the frame mount for a larger bolt too.

 

[JimLee]

Does anyone know if there is anything you can do to increase the torque on the track bar bolts? If I understand correct, torque settings are limited by the bolt itself and over-torquing could lead to snapping the bolt. Correct? Obviously I can't go to a larger bolt because of the TB bushing itself.

Lot of TJ and JK guys used to upgrade to grade 8 hardware as mentioned above to achieve a higher torque.

 

[Halstem1]

Lot of TJ and JK guys used to upgrade to grade 8 hardware as mentioned above to achieve a higher torque.

ok. I was looking up torque specs for a 9/16" grade 8, and I think its relatively the same as the factory 10.9 bolt. Maybe not. I'll do some more looking. I think both show a spec around 125#. I want to torque that thing to like 150. haha.

 

[JimLee]

ok. I was looking up torque specs for a 9/16" grade 8, and I think its relatively the same as the factory 10.9 bolt. Maybe not. I'll do some more looking. I think both show a spec around 125#. I want to torque that thing to like 150. haha.

Some sites show a 9/16" grade 8 with a torque value of 153 (dry). I'd do 150 on a quality 9/16" grade 8 bolt without stressing over it.

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