Death Wobble can of worms

[FlHoundDog]

I just joined and I hate to open a can of worms, but I have to. first details:
1993 Jeep Cherokee Country XJ, 2wd,2 door. 31 in tires.
VIOLENT shaking after hitting bump at 45 mph or more.

I started researching and this is apparently a common topic.
I see a lot of "get your tires balanced" but the jeep does not have any typical balance issue. Smooth as glass unless you hit the mystery bum @ 45 and then it's like an earthquake.

So my my question is why?http://www.xjtalk.com/images/smilies/crazy.gif Why will a balance help when it appears they are in balance? Is there some XJ issue, or large tire issue I am unaware of since I am new to both?

I am leaning toward swapping the steering damper this w/e. Then doing some close inspection of all front end parts.

[SteveMongr]

A steering damper is not necessary on a properly functioning steering/suspension system. It will only mask any issues you are having.
The death wobble is coming from worn and/or loose parts.
First suspect is the track-bar. Check the end bushings for wear, check bolt torques including the bracket.
Also check all the control arm bushings and bolt torques as you stated.
Also important is every joint (tie-rods) on the steering.
Note; I still run a steering damper, just want to make the point that is not required for the steering to function well.

[jimmixj]

Hi Sean, you didn't mention if your xj is lifted or not. Also, is this a recent development, was there something else changed that started the problem or has it always been there? Worn parts are a likely culprit but it is possible to have DW occur because of too little positive caster. Ever get a shopping cart with a wobbly front wheel? That's a scaled-down version of your wobble. Just some food for thought...

[xj4life2]

Death wobble is caused by two things alignment and bad bushings, 99.9 percent of the time the track bar is the bad guy, replace the bushings and reinstall , be sure you get it real tight , drive and retighten. Check control arm bushings while your there.

[FlHoundDog]

I already lined up a new track bar. I'm going to go through the entire front end now. The jeep is lifted with a 3" rough country lift. I got the jeep in September, the Death wobble has happened a hand full of times since. The damper seems to have cured it or at least masked the real issue.
Thanks

[SteveMongr]

Knowing the 'caster' numbers will help. One sign of not enough caster is after a turn the steering wheel does not want to return to center.
Generally I do an alignment at home and then take it to a shop for a printout, usually free. Low caster causes steering issues like wandering. It can aggravate death wobble but is not the cause.
Here is a link for DIY alignment and how to read caster.
If you have stock control arms and the bushings are worn, it's cheaper and easier to replace the arms since they come with bushings already pressed in.

http://go.jeep-xj.info/HowtoAlignment.htm