Sorry to muddy up your thread with another long story Mark, but figured this was as good a spot as any to throw in my experiences over the years.
As a refresher for those that have been listening to me preach on about Death Wobbles on the internet, and for anyone that has not heard this before, I have been fixing Death Wobbles since before (as far as I know) I coined the term. First time was in '70 on a '67 Buick Wildcat (one of the non-solid axle vehicles James brought up) and the next was on a 2wd Dodge pickup, and the third was on an International 2wd pickup.
The next one was on my '71 Bronco in about '79-ish. The one after that was a TTB Ford in approx. '81-ish. Not long after this was when I came up with the (tongue in cheek) term "Death Wobble" because it was at a time when we were adding the word "death" to practically every other word or phrase as a way of jokingly adding more drama.
But in this case, Death Wobbles don't really need any more drama! They're pretty dramatic in themselves.
Not long after, I got my first job at a 4wd store. And then we came across them now and then and I would entertain the customers (or scare them) when I called their experience a Death Wobble.
Which is why I get my hackles up every time I hear someone describe their mild shimmy, or vibration as a Death Wobble when all they have is a mild shimmy that comes and goes. Or even a wobble from an out-of-balance tire, but one that never gets that out of control feeling of a true DW.
As James mentioned, along with the other things that can "allow" it to happen, the prime culprit in my mind is always the tires. ALWAYS THE TIRES!!! (sorry for shouting!)
I know in the Jeep world, many have been fixed by correcting the trackbar bolt mis-fit, or coming loose. Same, but to a lesser extent, in the Bronco world. Even some F250's have supposedly had their wobbles fixed by correcting a trackbar issue. Even some that say theirs was cured with a steering stabilizer! I can't say it didn't happen. Just that I'm surprised if it did.
And I still say it starts with the tires.
In fact, I was completely shot down on a Jeep forum for saying such blasphemy, when we were discussing the wobbles being "caused" by the TJ trackbar debacle. I even tried arguing that not every vehicle with a loose trackbar has a wobble, and not every wobble is fixed with a trackbar fix. Even members in that discussion had not fixed their wobble with trackbars, but had done so with tires.
Didn't stop the calls for my hanging for daring to go against their wobble expert. Oh well...
When I had it on my '71, I knew exactly what it was. I even knew when it happened. I had damaged a tire with a mild curbing turning into, of all places, my local Taco Bell!
But since I was due for some new parts anyway (and forgot to think about the money), I replaced, one at a time, literally every front steering and suspension part, even the springs and steering gearbox, before rotating my tires. Including purchasing (last part replaced) a brand new steering gearbox from Ford. But since it was only $175 bucks, even back then I thought that wasn't too much to add. Turned out to be way better than my old one, so that was a win!
But nothing fixed the wobble. I could repeat it at will, by turning on to one of two local streets and hitting the same bump at anything over 25mph or so.
Rotated my Armstrong True-trac tires front-to-back tire to the back, and voilá! Never had the wobbles again. Pretty much knew it would fix it, but really wanted to make sure, even if it cost me more money.
Just wore out that set the rest of the way without rotating them back, and have never had it again on one of my own rigs. Even though I've had worn out parts over those years.
Even when trackbar bushings wore out, lower bolts cracked their welds, and upper frame holes wallowed out. The truck would wander something fierce, but never wobbled.
Going back to the Buick, we developed the wobble on a short trip, then it would occasionally repeat itself for the next couple of months. Not often enough to think something was in dire need of replacing, and not easily repeatable that we noticed, but eventually it just got tiring. First time it had ever happened to dad (who was my original car guru) so he didn't have an explanation for it. Took it in to a shop to have whatever it needed fixed, and replace whatever steering and/or suspension components needed.
There, one old guy (remember, this was in '70, so the "old guy" in this case had really been around in the old days!) said "I know exactly what's going on" and proceeded to rotate the tires. I really don't remember if he did one at a time, or both. But when it went away, we eventually replaced one or both of the tires that were now on the back, and never had it again.
The tires were almost new, so replacing just one or two was not a bad thing. I think even those big beasts (big-ass Buick remember) were something like $40 bucks a piece.
So at least in my own personal experience, with six rigs in my own circle, then probably ten more working at the local shops, and then probably another ten or so working outside with 4-Wheel Parts and various suspension installers, it has literally been a bad tire, or tires in every single instance.
Were other parts worn out? Probably. Some probably wore out prematurely from the wobbles! Some may have been worn out in other instances, but ultimately only the tires were replaced. Or only the tires fixed it.
To your particular case pcf_mark, I can't say that it's only one, or two tires. In at least one case I worked on, it was at least three, if not all four!
A few years ago, a brand new Bronco-friend (literally that day!) saw my name on the Yahoogroups list and here and on Broncofix, and got in touch to see if I could help with a scary steering issue. He was driving his brand-new-to-him '70 from Los Angeles back to the Berkley area. White-knuckling it up I-5 was not making him very happy with his purchase, needless to say.
It was pretty tricked out, but shook and vibrated and wandered all over the place. When he got to my house we saw that one hub was smoking hot, and the PO had put on two steering stabilizer shocks in such a V-pattern that they were binding up. Well, after fixing things we found out why!
Jacked up the front and the driver's side wheel literally fell off! Found a new spindle and bearings locally, put it all back together without the stabilizers, and only got about 1/8 mile away from my house on the test drive and got one of the worst Death Wobbles I'd ever seen! And since it was his first, 'ya should'a seen the look on his face!
No bumps or speed needed. Anything over 30mph and the truck started shaking. Couldn't drive it that way, so now that we knew why the PO had put the shocks in a bind, we put it back together and he made it home.
New Bullet Proof steering linkage and trackbar, new ball joints later, and still the wobbles. New tires and done...
In his case it turned out to be at least three bad BFG 33x9.50 Mud T/A's.
So still tires for me...
For me claiming to have coined the phrase "Death Wobble" in the first place. I can't say I'm the only one that ever said that of course. Or that I was the only first person to say it. But I can at least claim to be one of the earliest adopters of it. Since it was well before the internet, things like that did not travel as fast as they do now. But I know I spread it at least around here before it became a "thing" that everyone knows today. Even if some still get it wrong when calling a shimmy a wobble.
And now you know why every time this comes up, the first thing I mention is the tires. They don't have to be old and worn. They could even be brand new. But, at least in my opinion, they are the only thing with the weight, leverage and location to create the conditions for a true Death Wobble.
Paul
I had big n small on my homebrew VW baja bug back in 1974 or so. Scary.
