Death wobble despite trying (almost) all solutions

I know there are lots of threads, and a checklist for troubleshooting death wobble - but I've done just about everything and still it happens, so I'm seeking advice.

My Jeep is a 1993 4.0 XJ, now on 130k miles, completely stock, no lift, and I've owned it from new. Rarely used for wheeling or serious off-roading, never hit anything. Both front shocks were replaced at about 60k miles and front discs (rotors) and pads at about 110k miles 2 years ago. Tyres only a few years and 5k miles old.

Over the last 3-4 months the front end felt increasingly loose and floaty, and hitting any unevenness on the road at over about 45mph caused the front-end to shake like a jelly. Not so much the rhythmic DW as an unstable shaking (a colleague said it felt like the lug-nuts on a front wheel had come loose!). The front also felt very loose in general driving, cornering etc.

Given the age and miles I decided to give the front end a serious overhaul. Turned out the driver's side shocker was very tired and feeble anyway - which I guess explained much of the looseness. So.... I replaced ALL the front steering and suspension bushes with a complete poly kit, fitted new tie-rod links/ends, and replaced the shocks with a pair of new Rancho shocks. One U/J had been replaced 6 months ago, so I replaced the other one too. Couldn't see any slackness in the steering box mounts or other chassis mountings.

About the only thing I didn't change was the steering damper (I have never had any of that predictable steering-wheel shake at certain speeds which is typical of out-of-balance wheels/tyres).

Then I had the alignment adjusted and checked after all these replacements.

First impressions - the Jeep was transformed. Solid and steady as a rock again, all felt normal in regular driving. It still does, 98% of the time. BUT - in the last couple of weeks, a problem has (re)appeared. If a front wheel hits a significant irregularity like a manhole cover or pothole at anything above 45mph, it sets off a serious wobble. Not every time: seems to depend on how big the hole or the bump is, and what speed I'm doing. It's a different kind of wobble to what happened before. Not a floaty unstable jelly-like shake, but a serious almost hammering vibration that is much more severe than the loose wobble that occurred before I replaced all those parts.

I'm baffled. Having checked and replaced most of the items on the to-do list, I can't understand why this particular problem is occurring. What have I overlooked, or what else can I do? Anyone got any ideas?

check the track bar bushing and tie rod end. they are usually the culprit

1990JEEPXJ said:

check the track bar bushing and tie rod end. they are usually the culprit

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x2.

I has similar issues, trackbar replaced and voila!!..

a bad steering stabilizer wont cause DW, its merely a band aid if your steering is good you dont need it.
but it doesnt hurt to replace it if it is bad.

how new is the trackbar?
i second checking the trackbar bushing and TRE.
have someone crank the wheel back and forth and watch the trackbar
is the trackbar bushign at the axle end good?
is the trackbar TRE at the frame good?
then crank on the 4 mounting bolts for the trackbar bracket. make sure that thing is tight as hell. if its even a little loose it can casue DW. i know it from experience, it happened to me one day. cranked it down, then it was gone.
are there any frame cracks around the trackbar bracket?
check ball joints for play. shake tires around (off the ground first)

check control arm bushings. check all upper and lower control arm bolts for tightness.


when was the last time tires were balanced?
ive seen bald unbalnaced tires casuse DW , on my jeep actually...

id put money on a bad trackbar and/or a loose mount.

i drove back from the rubicon in september from tahoe to sac with 2 loose axle side control arm bolts ready to fall off, same for the lowers, and a slightly loose frame side trackbar bolt with no DW.

so it makes me think your trackbar bushing and/or TRE are totally shot.
replace it , crank on the mount (18mm bolts) and go from there

Check the track bar for sure, and the play in your steering box. Also, in researching my own incurable death wobble I came across two other scenarios that have caused problems for other people that are less common, but may apply to you. The first happens when you jack up the body of the jeep to replace bushings. The axle is drooped beyond stock ride height. If you tighten the control arm bolts with the axle drooped, then lower the jeep to ride height, the bushings will twist and store energy. The second was a guy who claimed that his stabilizer failed in such a way that it had a dead spot at center and when you pushed through the dead spot, resistance would increase and rebound the stabilizer like a spring, also storing energy.

I would change the steering damper,
I Know, I Know, it will only mask the problem.

But remember the Mfg put it there for a reason, I have had jeeps wobble with everything brand new, tight & in perfect alignment (Just like your own); then I changed the damper & like magic all the wobble went away:yelclap:!

OME makes the best one.

Your description of work performed comes up a little short.

Did you replace the UCA and LCA bushings, at both ends?

X2 what Joe said. Cheap enough to buy new arms with the bushings installed, and that only leaves the two on the uppers on the axle to play with. I cannot stress the Track bar enough! If you haven't already, replace it now. In my experience (we have four of these beasts, over 11 years), the track bar has been the biggest contributor to front-end problems. And, while you're at it, no urethane control arm bushings. I wish I had all the time I spent monkeying with them back, and I ended up replacing them with OEM control arms. The suspension engineers used rubber bushings for a reason!

Thanks for all the replies and comments so far.

The UK versus US technical terms can be a bit confusing eg track rod v panhard rod, drop links, etc etc.

But Joe, if UCA and LCA are Upper and Lower Control Arms, aka Upper and Lower Suspension Arms - yes, all four bushes (bushings) on each side replaced with poly ones.

So far the majority view seems to be track rod and/or tie rod ends as the prime suspects, though Lightfoot raises some other, unusual possibilities. I'm ready to consider or explore anything!

Ok, well nothing substitutes for laying under the front end, with a bright spotlight, while a second pair of hands turns the wheel slowly left/right. Observe ALL of the components for odd movement. Tie rod ends, draglink ends, trackbar (panhard rod) ends. Observe the frame/axle mounting points. Observe the steering gear box--there is an aluminum spacer between the box and unibody that likes to crumble. Steel replacements can be had from various makers.

heyhar said:

..... Cheap enough to buy new arms with the bushings installed.........And, while you're at it, no urethane control arm bushings...... The suspension engineers used rubber bushings for a reason!

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Heyhar, I wish that first comment were true! I'm over in UK and ANY Jeep parts, OEM or alternative, are far from cheap. Any spares reflect the shipping costs and UK import taxes, so whether from a UK dealer or ordered direct from the US (I use Rock Auto) even a $10 item ends up costing minimum $50, and anything large, heavy or long has to be obtained via local dealer, often takes weeks to arrive, and costs an arm and a leg.

That's why I can't try the usual trick of "change out a part and see if that works". Have to be very sure of what I need to replace before I start ordering!

I opted for poly(urethane) bushes because although costly, they weren't all that much more than OEM rubber and because I believed/hoped that they would be more durable and less prone to perish, wear or rot - and thus better value. No doubt there are people for and against such an alternative. Fact is, I've done it, so I'm stuck with the poly ones now!

joe_peters said:

Ok, well nothing substitutes for laying under the front end, with a bright spotlight, while a second pair of hands turns the wheel slowly left/right......

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Joe - this might seem a dumb question (I'm not a mechanical engineer, just what you call a "shade tree" DIY-er). The checking of the front end for odd movements - do you do it with wheels on ground and therefore suspension under load and steering against some resistance? Or with front end jacked up, wheels dangling, and steering turning freely?

Wheels on the ground.

When checking the ball joints or unit bearings you will have to jack the frond end up so you can wiggle the tires and wheels, checking ball joints 6 and 12, unit bearings at 3 and 6, if you get wiggle/wobble replace the part.

Back to the poly--it will give you a harsh ride. If cared for--use a proper poly lubrication--they should last longer than OEM.

br1anstorm said:

I opted for poly(urethane) bushes because although costly, they weren't all that much more than OEM rubber and because I believed/hoped that they would be more durable and less prone to perish, wear or rot - and thus better value. No doubt there are people for and against such an alternative. Fact is, I've done it, so I'm stuck with the poly ones now!

Click to expand...

I too tried the red Daystar bushings about eight years ago, hoping for crisper handling, and the fact that a kit, with every bushing under both ends of the car was about a hundred bucks. I didn't mind the stiffer ride, or the occasional squeaks (which became progressivly worse), but I felt that it was giving me a different kind of DW, not the slow, rythmic gyrations, but quicker, higher frequency vibes. They settled quick, but it was as if the DW was sped up to a higher level. It seems that the energy of hitting a bimp or seam in the road was not absorbed, or 'damped', but rather shot through the various components, back and forth, like a bell ringing. The Jeep handled better than ever, but the extra vibe or two was not an acceptable trade-off. Since then, OEM type control arms are all I'll use. Some of the straight-ahead tracking is gone, and it's 'jeepy' again, but if I wanted a Ferrari, well..........

Don't discount the 'band-aid' steering damper, either. Yeah, a new one won't fix a DW allowed to happen because of one or more worn components, but it will help absorb some of the energy created in a bump or other suspension event. Also, it may make an easier task of it for the steering box, as it damps the lateral motions of the tie rods, saving the box from taking the beating all alone. I've tried various ones, including a Rancho, which quickly developed a loose, dead spot (and wasn't covered by warranty, as their claim is that it was beaten) and an Old Man Emu, which was the cost of three OEM jobs, and no more effective. Now, it's strictly stockers!

Don't know if it will help but Kevins Offroad sells a DW resistant trackbar and bracket. He explains that deathwobble is a lateral movement of the wheel like a shopping cart. His beefed up bracket in particular make lateral movement less likely because of the way it mounts to the trackbar and because the bracket is made more rigid due to a ridge he puts into it. Apparently there are a number of people who use it and it does work.

http://www.kevinsoffroad.com/cart/index.php?main_page=index&cPath=42_64

I bought it years ago, and I had some correspondance with Kevin regarding the hardness of the bushings. He claimed they weren't as hard as he'd specified, and sent me the revised pieces. It was hard to tell if the setup was doing much good, as I was experimenting with Urethane bushings at the time, and was getting all sorts of wierd vibes, like I explained in an earlier post. The track bar is currently collecting dust under my work bench, as I've put the front end back to completely stock, and it acts now as it should have all along. I guess my advice would be to buy the best parts you can, like a Moog track bar. I've had good results using the OEM control arms that Quadratec sells, and the price isn't bad, either.

While I'm at it, I can't stress enough to make suer the tires (tyres?) are balanced good, and that they're 'round'. In the last five years, I've had one or more tires of two different matched sets become out of round, and some less-astute tire jockeys will balance them, and send you on your way. I guess you can balance an egg, but it's still shaped like, well, an egg. Both times I had this happen, they were balanced numerous times, to no avail, and I even had the owner of a well respected front end shop tell me I was crazy for even suggesting something that he didn't detect. I bought a new set of Firestone Indy 500 tires (admittedly not the 'aggressive' tire you'd find on a Jeep), and I've never driven a better tire on any of my heaps! Just my two cents worth!

heyhar said:

I too tried the red Daystar bushings about eight years ago, hoping for crisper handling, and the fact that a kit, with every bushing under both ends of the car was about a hundred bucks. I didn't mind the stiffer ride, or the occasional squeaks (which became progressivly worse), but I felt that it was giving me a different kind of DW, not the slow, rythmic gyrations, but quicker, higher frequency vibes. They settled quick, but it was as if the DW was sped up to a higher level. It seems that the energy of hitting a bimp or seam in the road was not absorbed, or 'damped', but rather shot through the various components, back and forth, like a bell ringing. The Jeep handled better than ever, but the extra vibe or two was not an acceptable trade-off......
Now, it's strictly stockers!

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That description nails it exactly! I got the Daystar kit (price has gone up a bit!) and that picture of the quicker, higher frequency DW is spot-on. It happens very rarely (about three times in the last two months), and only when a particular combination of speed and road-bump unbalances things and sets it off.

But the uncertainty of not knowing when it's going to strike is almost worse than the earlier problem of a familiar, almost predictable, jelly-like looseness and gentle wobble which happened more or less every day on a less-than-perfect road surface.

I can't say I relish the thought of removing all the (new) bushes and fitting a set of OEM ones. But now I wonder if the other possible options - change steering damper, and/or change trackbar - are worth doing!

Well, you might try changing things to change the "harmonics"--try adjusting your tire pressure up/down, might make enough of a difference.

With your mileage and age, a damper and trackbar are just about mandatory. My '92 is on its fourth trackbar (fifth counting the original) in the 130k miles and eleven years I've had it. The original was toast at 100k, I put on two stockers, the Kevin's hogleg, and now a stocker, at a little over 200k. If I had gotten a Moog, I wouldn't have a colorful tale to tell.That being said, my '96, at 154k, still has the original trackbar, and the front end is fine. This one, though, has throttle body sensor gremlins. Oh, well, at least it steers good.....