Well, after moving my axle forward tonight I beleive that I have developed a case of death wobble.

What exactly is death wobble? and what causes it?

As I was driving down the road at about 15-20 I hit a small bump which seems to cause some sort of chain reaction and the front end seems to shimmy side to side. It about scared the tar out of me. Is this death wobble?

Death Wobble is the ultimate symptom caused by a billion problems. It is the universal symptom... much like a headache is the universal symptom for medicine. What caused the headache is what needs to be treated...
* that gaping head wound and the broken skull?
* loss of blood and a ruined carpet?
* stopping drinking alcohol or beer?
* drinking too much alcohol?
* too little caffiene?
* too much caffiene?
* allergies?
Etcetera, etcetera, etcetera....

A partial list of causes for death wobble includes: out-of-round tires, poorly balance rims, insufficient toe, loose shackles, worn bushings/ball-joints/bearings, inadequate kinpin/ball-joint preload, too little caster, too much caster...
All that and the net result feels much the same: front wheels that shimmy and hop uncontrollably at certain speeds. At its worst, DW can feedback throughout the whole steering/suspension system in a harmonic resonance that can put you out of control and into a ditch.

Solutions... well, there is no one-size-fits-all solution. There are a host of different solutions for different vehicles based on the individual root cause of the universal symptom, DW. A partial list of solutions includes: running low tire pressure to heat the carcass into higher compliance, balancing rims/tires, front-end alignment (caster, toe, etc), replace loose/worn bushings/ball-joints/bearings, shim kingpin... and maybe even more band-aids, such as running low tire pressure to damp/change the resonant harmonic of the steering system, castering artificially high, over-tightening bolts to preload bushings, and of course, the venerable steering stabilizer (more must be better, right?). Still other modifications exist that may damp the DW symptoms without actually changing the cause -- some folks talk up hydraulic steering as the obvious solution to DW... personally, I think it is just another band-aid (albeit one that helps in the boulders). It's way better, IMHO, to fix the problem and eliminate the symptom than it is to cover it all up and hope for the best. When you hear a belt squealing its death knell, do you turn up the radio or break out the tools and fix it RIGHT?

I'm always frustrated when I see someone touting 'their' fix as the silver bullet that will take care of ALL death wobble. <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> There's rarely just a single silver bullet, you'd need a whole box of ammo to shotgun most DW -- it can derive from soooooooo many sources. BTDT. <img src="/forums/images/graemlins/frown.gif" alt="" />

Tell us more about your setup -- what you've checked and what you suspect....

Randii

I am thinking it is the caster. Up until I switched the tie rod from the hi steer arm down to the normal tie rod location I didnt have any death wobble. the normal tie rod location is at a slightly different angle than the hi steer arm was.

At this point I only had wobble once, and it wasnt that bad and it was able to recover itself.

After this I switched up my springs and moved my axle further forward. (By this I mean I am running isuzu springs SOA with a shackle in the rear. I started with the long end towards the front (25 inches to the front spring hanger), then I switched it to the short end heading to the front spring hanger.) Because I shortened the length of the springs to the front and my spring hanger is considerably higher than my shackle it changed my caster. Quite a bit in fact. Enough that I can notice that my steering knucle is not parallel with the ground.

Here are the solutions that I see so far. I can move the spring hanger further down and make myself some bigger fangs but at the same time make my spring eyes closer to level while at the same time lifting myself some as well.

Or I can cut and rotate the knucles even further to correct the caster.

I am thinking it is the caster.
This was gonna be my guess as well. being leaf sprung, that narrows out a lot of geometery issues with the track bar, etc. Then what tipped me off is you said you redid the front suspension, and obvisouly you didn't have it before. placement of the front springs definitely has an effect on caster.

Up until I switched the tie rod from the hi steer arm down to the normal tie rod location I didnt have any death wobble. the normal tie rod location is at a slightly different angle than the hi steer arm was.
tie rod? the rod that connects both tires? or drag link, the rod that connects wheel to steering box? i think there may be some confusion in terminology. regardless, angle of the drag link/tie rod should have very little to do with death wobble if everything else is configured correctly.


and my spring hanger is considerably higher than my shackle it changed my caster. Quite a bit in fact.
do you know how much? i'd measure your caster so we can talk in numbers here.


here are the solutions that I see so far. I can move the spring hanger further down and make myself some bigger fangs but at the same time make my spring eyes closer to level while at the same time lifting myself some as well.

Or I can cut and rotate the knucles even further to correct the caster.
sounds oh too familar of the thoughts going through my head not long ago. now maybe you understand how my rodeo got so big so fast <img src="/forums/images/graemlins/evil.gif" alt="" />

-Rob

Not talking about the drag link.

I am talking about the tie rod.

I couldnt clearance the pitman arm or the leaf springs properly with the tie rod to remain on the hi steer arms. I had to move the tie rod to the original location undeneath the leaf springs.

I will get some measurements on the difference of the spring eyes.

ok, i'm just a little confused because i thought you said the angle of the tie rod changed. whether its up on the high steer arms or down on the stock knuckles, its angle relative to the axle should be the same. Its stroke may change and the ackerman's angle may change depending on the high steer arms, but its overall angle relative to the axle should be the same.

Regardless, the tie rod, assuming its ends are tight and free of play, should have nothing to do with death wobble.

-Rob

I will also try and post some pictures so you guys can all see what I am talking about.

There's my orginal setup, you can see the difference in between the rear eye and front eye. While this didn't cause death wobble, it was enough to cause caster problems. I later moved my axle forward a significant amount, which brought the rear eye furthur up in the frame bend and leveled the spring more.

-Rob

Good luck!!!!! Hope you can figure it out, and it be easy and cheap to fix

My hubby just had this happen to his 74 Chevy. It was the drag link in his. Which just happened to be the cheapest solution lol His front end needs some work though too, which is getting done soon. I bet he can sympathize with you though. He got freaked out when his truck freaked out LOL Parked it and got a ride home.

Just wanted to wish you luck mainly

Virginia

you can improve your caster by lowering the pinion angle (and pulling the upper ball joint back in the process). But that may introduce drive shaft fitment issues.
Do you have a magnetic degree gauge?

Keep a close eye on you upper ball joint in relation to the lower. Don't let the upper get verticle or in front of the lower one. 4 to 10 degrees behind is preferred.

When you lower that pinion and subsequently increase caster, you will have a more stable front, but you may face front drive shaft angle issues.

My Cherokee D44 is ideal in caster with the pinion angle pretty much parallel to the ground (as was stock installation). Handles well and is about 8 to 10* caster (stock), but I have the pinion angled up with only about 2* caster; Incorrect technically for drive shaft angle and unstable, but I needed it for the front shaft fitment. My front drive is limited in usage and at very low speed.

cutting Knuckles and moving them and rewelding is the perfect way to do it, but most people don't have the required Jigs to maintain alignment when welding. Takes a very good experienced welder to anticipate how the weld will contract the joint as it cools, and as it contracts change the angle of fitment in welded parts.