Here is a familiar issue: death wobble

[MarkAllan]

1999 TJ - 3 inch lift with caster adjustment bolts (no adjustable control arms), front end components inspected by a suspension shop and all good. I had Death Wobble so took it in for an alignment seemed to be better but that was temporary. The wobble came back. Looking over the alignment report, the caster spec says it should be between 6 and 8 degrees...mine after the alignment is 2.5 on the left and 3.9 on the right. I do not have adjustable control arms and was told I don't need them. I'm wondering if that is bad advice....thoughts?

Also, my camber should be between minus 0.9 and 0.4 degrees as per vehicle spec but my left side is minus 2.8 and the right is minus 0.6...will this contribute to wobble?

Any advice or suggestions would be great. Thanks!!

Update:
I got the jeep up on jackstands (under the axle not the frame) and went over everything...no play in any ball joints, no play in the wheel bearings and U-joints are smooth with no play. I went back to the alignment shop and the owner (not the tech that did the alignment) said that something wasn't done right and said that I should bring it back. I'm thinking before I do I'm going to install lower adjustable control arms I just don't know if I need to change the upper control arms too.

 

[Rickyd]

1999 TJ - 3 inch lift with caster adjustment bolts (no adjustable control arms), front end components inspected by a suspension shop and all good. I had Death Wobble so took it in for an alignment seemed to be better but that was temporary. The wobble came back. Looking over the alignment report, the caster spec says it should be between 6 and 8 degrees...mine after the alignment is 2.5 on the left and 3.9 on the right. I do not have adjustable control arms and was told I don't need them. I'm wondering if that is bad advice....thoughts?

Also, my camber should be between minus 0.9 and 0.4 degrees as per vehicle spec but my left side is minus 2.8 and the right is minus 0.6...will this contribute to wobble?

Any advice or suggestions would be great. Thanks!!

Sounds like you have a bad wheel bearing or ball joints on the left side letting the camber go out of spec.

The play in parts combined with tires that are- out of balance,out of round,or rims that don't run true will store and release energy in scary ways. AKA death wobble.

Swap rear tires to front,get them balanced and spun with an eye towards how true they spin.

Look up dry steering test and check your parts again,especially the left side.

Never take a tire shops word for anything. They don't get paid enough to think...

 

[MarkAllan]

Sounds like you have a bad wheel bearing or ball joints on the left side letting the camber go out of spec.

The play in parts combined with tires that are- out of balance,out of round,or rims that don't run true will store and release energy in scary ways. AKA death wobble.

Swap rear tires to front,get them balanced and spun with an eye towards how true they spin.

Look up dry steering test and check your parts again,especially the left side.

Never take a tire shops word for anything. They don't get paid enough to think...

Thanks Rickyd! All good advice. I'm going to go back to the alignment shop and press them to reinspect the front end however I'm going to add wheel bearings and ball joints to my to-do list. I'm going to go ahead with adjustable front lower control arms to see if I can't get the caster within spec and eliminate that as a possible cause. I'm also going to switch out my rims and tires....I've been wanting to go with a little less aggressive tread and bigger rim size for street driving. Right now I'm running 33x10.5R15 and I'm thinking of going to 265/70R18. I'll keep the 33's for off roading but my off roading really is just some logging roads...pretty tame stuff.

 

[AndyG]

Rickys post is insightful- the spec leads to suspicion of the ball joint.

Otherwise alignment and deathwobble are not highly interdependent-

Swap front tires to back and see if its bad wheel, broke belt, weight lost or similar issue that way

You need perfectly balanced tires and good connections as a baseline for good TJ driving performance-

There is way way more going on up front when the rig is in motion, but you don’t want anything to create the auto oscillation or allow it basically.

And it can be one or the other or any proportion of both-

No one knows the precise tolerances or lack of that are at play but you sure know it when it happens. Loose rigs have been known to be ok til all new parts go on.

It seems 45-50 mph is the magic speed that generates enough precession to trigger it.

Keep us posted. It helps everyone.

 

[MarkAllan]

Rickys post is insightful- the spec leads to suspicion of the ball joint.

Otherwise alignment and deathwobble are not highly interdependent-

Swap front tires to back and see if its bad wheel, broke belt, weight lost or similar issue that way

You need perfectly balanced tires and good connections as a baseline for good TJ driving performance-

There is way way more going on up front when the rig is in motion, but you don’t want anything to create the auto oscillation or allow it basically.

And it can be one or the other or any proportion of both-

No one knows the precise tolerances or lack of that are at play but you sure know it when it happens. Loose rigs have been known to be ok til all new parts go on.

It seems 45-50 mph is the magic speed that generates enough precession to trigger it.

Keep us posted. It helps everyone.

Thanks AndyG! It is that 45-50 that seems to be the wobble zone...However before the wheel alignment it would happen at around 30 mph. I suspect this isn't a singular fault issue. I'm going to do the tire swap to new rims and rubber, all ball joints, adjustable control arms and take another look at the wheel bearings and u-joints. I will start with a Monday morning revisit to the alignment shop and see what they have to say. Will update as I progress.

 

[MarkAllan]

Update:
I got the jeep up on jackstands (under the axle not the frame) and went over everything...no play in any ball joints, no play in the wheel bearings and U-joints are smooth with no play. I went back to the alignment shop and the owner (not the tech that did the alignment) said that something wasn't done right and said that I should bring it back. I'm thinking before I do I'm going to install lower adjustable control arms I just don't know if I need to change the upper control arms too.
The blue hand written numbers are what the repair manual says it should be however that is without a 3 inch lift so I'm not sure if that allows for an acceptable variable.

 

[Moglocker]

Update:
I got the jeep up on jackstands (under the axle not the frame) and went over everything...no play in any ball joints, no play in the wheel bearings and U-joints are smooth with no play. I went back to the alignment shop and the owner (not the tech that did the alignment) said that something wasn't done right and said that I should bring it back. I'm thinking before I do I'm going to install lower adjustable control arms I just don't know if I need to change the upper control arms too.
The blue hand written numbers are what the repair manual says it should be however that is without a 3 inch lift so I'm not sure if that allows for an acceptable variable.
View attachment 589277

Jks sells non adjustable lower arms that are longer to give you the right castor.

 

[MarkAllan]

Jks sells non adjustable lower arms that are longer to give you the right castor.

Thanks Moglocker, I'll look those up!

 

[Rickyd]

Thanks Moglocker, I'll look those up!

Get adjustable arms. Jks doesn't know what you need

 

[Moglocker]

Get adjustable arms. Jks doesn't know what you need

Yep,it doesn’t say what degree they are set for (probably have to callem)or get adjustable.

 

[MarkAllan]

Yep,it doesn’t say what degree they are set for (probably have to callem)or get adjustable.

I think for the little bit of price difference I would much rather have adjustable.