Stolen from UTAH 4X4 Club
http://www.utah4x4club.com/index.php?showtopic=364
First, what causes death wobble?
Theres a number of things that can contribute to it, but there is a couple that top the list. This list is in order of most common to least common causes.
1. Track Bar mounts, upper and lower.
2. Caster/Camber
3. Wheel Bearings
4. Allignment
5. Tire Balance
6. Tie rod ends/drag link
Now on how to fix it all, Ill try use diagrams when I can.
1. Just tighten the lower axle mount and the upper frame mount. What usually happens is the bolt will either become loose, or the bushing will go bad. Most commonly happens when a used track bar or a stock one is being used with alot of lift (5"+).
2. Heres one thats overlooked alot when lifting a 4 linked vehicle. (thats your suspension type) In the diagram, the red line is your outer knuckle, if it is not within .08* of center on a 90* level, you will get an over toe either in or out.
3. These are also known as unibearings, there the wheel mounting surface (WMS) for the front axle, they then mount to the knuckle. If these go bad there is an easy way to check. Jack the axle up so the tire is no longer in touch with the ground and push/pull the tire in and out from top to bottom. If theres a little play it is going bad, usually 1-2 cm, if theres alot of play, 1-2 in it is bad and needs replacing. They will go bad, its not a matter of as is when. With tires 32"+ its a common headache. You can get pretty decent replacements at any parts store for around $150 ea.
4, and 5 are pretty self explanatory, maintain your rig and take it to the tire shop.
6. If you didnt already know, even with a drop pitman arm, the joints on your steering will go bad. The drag link is the biggest PITA due to it only having 1 replaceable joint on the pitman end. The rest of the draglink has to be replaced to fix the lower mount. Tie rod ends (TRE) are fairly cheap at around 30$ or so a pop. There is a fix for the draglink. Cut the outer joint off. Take another draglink, unscrew the turn buckle style adjustment. Cut the turn buckle in half. Weld the unthreaded end to the cut lower end of the draglink. Now you are able to replace both ends without spending 160$ at a time to replace the whole thing.
If theres something I missed add it.
Brian