I have been experiencing frequent "death wobble" after going up to 4" of lift in the front and 37" tires. It is mainly when I hit a bump at around 35-40 mph. I put the Jeep on a computer alignment machine today and I have 4.8 degrees and 5.0 degrees of castor at the front. I know that most people are running 6-8 with 37's but it doesn't seem that it shouldn't be this bad at 4.8-5.0. I don't have adjustable arms, but I did slot the front control arm mounts and tack-welded washers in place to keep them from moving around. I have the Teraflex adjustable track-bar, so I know that the axle is centered properly. I am kind of torn about what exactly to try first due to cash flow being extremely tight right now. I am pondering the possibility that it is being caused by bump steer, and possibly fixing it by installing a front track-bar bracket and a high steer drag link (the drag link is on the to-do list anyway). Anyone want to weigh in on this? Thanks in advance.

 

I think most of the death wobble problems come from loose track bars. Are you sure your are cranked down to 125 ft lbs. If so, maybe pull the track bar off and look for worn brackets, bushings etc.

You are not running any relocation brackets in conjunction with your track bar are you?

Caster shouldn't be the problem but with 4" of lift I would think that control arms are going to be desperately needed.

Also inspect the track bar brackets for cracks, etc. Maybe have someone turn the wheel while you look because they may not show until they are under pressure.

That's all the ideas I have!

 

What Rubimon said. 9 out of 10 times, death wobble is caused by a loose track bar. However, control arms or other suspension/steering compontents not tightened up to torque specs can cause this as well as improper toe-in adjustment (I doubt this is the case for you - that is unless you played with it already). I know you said that you tack welded washers on the slots of your control arm mounts but I would double check them as loose cam bolts would definitely be suspect here. Sorry, I wish I could be of more help but for now, I would start off with what you can do for free and that's to double check all your components and make sure they are torqued to the appropriate settings.

 

I recently started experiencing the same problem. I also believe I have a bent tie rod, causing me to have a tow in problem, like WOL suggested. Between the track bar issue described below and the tow in problem, I too picked up the nasty wabble. I pulled my previous post from onther thread for you to check out.

I think you hit the nail on the head about the weak steel brackets. I am running Teraflex lift and track bars, but I think this problem is common to all JK's.

I took my front track bar off today to check it out because I picked up a death wobble after my last wheeling trip. Tereflex had an issue with a shoulder on the track bar bearings that wasn't wide enough, so I wanted to check it out. My bearings are still tight, but the brackets are worn and gouged. I think this is a problem that we will see more of.

The OEM brackets are thin and soft. When you torque the bolts, the bearing shoulder and event the bolt dig into the bracket. As it wears more, the bolt loosens and you get play. The factory bolts are too small for the holes to begin with.

Teraflex is sending me the new revised bearings, but I plan to have some reinforcement plates welded on. I am going to use an after market Track Bar Relocation bracket on the axle end, but I haven't seen anything really nifty for the frame end so I may just have a shop make something.

And before anybody asks, yes I torqued and retorqued several times. I torqued them to 130 ft lbs.

Here's a shot of the frame end. I took a picture of the axle end, but it didn't turn out too good. Notice the gouge on the inside from the bearing shoulder and also the gouge from the bolt head. It also looks like the hole may be enlarged from loosening. By loosening, I mean as the bearing and bolt digs into the bracket, less torque on the bolt is achieved.

 

Thanks for the replies so far. Here are some answers to some of the questions posed:
1. The track bar is torqued down properly. I have checked it several times.
2. I have checked for cracks in the brackets, but haven't found any.
3. My toe-in is actually out right now, but I have had to adjust it alot lately and can't seem to get it to hold position very well. I don't know why, because it is tight at the adjustment bolt. I don't think this is the cause however because I have made various adjustments to it and it still has the problem after each adjustment.
4. All other suspension bolts are also tight.
5. The Teraflex bar I have already has the updated ends installed. I had the wobble with the stock track-bar as well and thought the Teraflex bar was going to help cure the problem.

Does anyone notice that their tires/wheels seem to dart back and forth while spinning/climbing obstacles even though the steering wheel is staying fairly straight? I have noticed that mine does it pretty badly. I was thinking that this may be due to steering components flexing under stress. Any more ideas on this?

 

I would have someone jiggle the steering left and right why you look for any movement in the front suspension components.

For your tie rod, take some of your wifes/girlfriends favorite red finger nail polish and put a horizontal stripe across the adjuster assembly for the tie rod. This stripe would let you know if any movement has occured in the assembly.

 

Toe is probably the problem. How are the tie rod ends? Your toe should not change. If you figure out why it is changing, then you will probably find the problem.

 

This is probably due to the limited slip feature where as one tire spins the brakes are applied to that wheel allowing the other one to gain traction. Depending what type of surface you are on it is probably alternating back and forth.

I agree with Igofshn, if your toe in is changing, something is slipping/moving somewhere. Try the line as mentioned above, that will eliminate or confirm one area.

 

I will adjust the toe and mark the adjuster with paint. I don't know why the toe rod ends would be worn out with only 6700 miles, but I guess they could be. That would force me to go ahead and build my heavy duty tie rod though...
Thanks guys.

 

I also experienced the death wobble thing.

It turned out to be the tera flex track bar I had was not built with correct bushings.

They warrantied it all out.

I learned an easy way to check for this problem.

1 guy gets down in front and looks right at the track bar mount points.
Another turns the steering wheel back and forth.
If the track bar moves at all (and I do mean at ALL) the bushing is bad and can kill you and/or others on the road.

Mine only moved maybe 1/64 of an inch. I mean I wasnt sure it moved it was so small. But thats all it takes to induce death wobble.

It has nothing to do with your castor tho you should fix that as well since your "come back" to center is screwed and your rig would be darty like that.
At least put on adjustable lowers as that will get you there but without the uppers the agle to the differential will be extreme with a 4" lift.
That will lead to early failure of the drive train (prolly at the joint).

Death Wobble is a good term for what happens as it was the single most frightening thing I've ever experienced other than saying " I do" 30 years ago...

The dartyness you are experiencing sounds to me to be exactly what I experienced before putting adjustable lowers on my 3" lift to get castor back. It wasn't just while crawling it was on the street even at higher speeds too. hit a small bump and fight to stay straight and centered.

Another thing I learned is my 35" Pro-Comp A.T.s want more air than stock, I now run 40lbs in the front and 37 in the rear.
If I'm towing I run the rear up to 45lbs.
They behave "right" at those pressures and in general big tires need big air too. some go as high as 60lbs max and guys around here run 50lbs in some too.

Anyway good luck and please please please check that bushing in the track bar. Tera flex knows all about it and will swap it out no question.
It was thier supplier that screwed up, making the bushings out of the wrong crap. But death wobble is SO extremely dangerous you have to fix it!
Period.

Safety 1st, then go nutz...