The "Death wobble"

[Wombatrage]

So, i have a 1989 2wd 2.5L MJ. The previous owner has done some questionable things to the truck.

 

For instance, the rear end is DROPPED two whole inches, and it has exhaust pipes from a 6 cylinder mustang (sounds like a dump truck) :doh:

 

but anyway, i was looking for a cost effective way to fix up my suspension without doing a complete over haul. The back is nearly bottomed out as it sits, and the front definitly needs shocks.

When i hit a bump a certain way, my truck will start a very small side-to-side shake, and it gradually gets worse, every shake gets a little bigger til you are about to rattle yourself off the road.

Someone told me wheel bearings, someone told me tie-rods, I dunno, what do you guys think?

And include a price estimate for the parts if you don't mind :cheers:

[dasbulliwagen]

Welcome to the club from Asheboro! Death wobble has a ton of different things that can cause it, from worn ball joints, worn tie rods, worn track bar, worn control arm bushings, bad wheel bearings, improper wheel balance, improper alignment including toe and caster. Without seeing your truck it would be hard to give any kind of estimate as to what youll need to take care of this. It could be just one of those things, or it could be all of those things. Get under there, look for stuff that looks like it might be worn or bad and start there. Also, to eliminate it, get your wheels balanced. Let us know what you find, and ask any more questions you have to get this done. We are mostly all happy to help. Good luck.

[Wombatrage]

Thanks a lot :D i think i am gonna start by dropping the rear and getting rid of the drop, and replacing the U-bolts when i put it back in.

 

after that is the shocks in the front, as they are visibly shot.

 

if that doesnt fix it, i will probably try wheel bearings or tie rod ends next.

 

I'll be sure to keep you posted as i work through it, and hopefully i can restore my pride as a jeep owner instead of being afraid of every little patch in the road and pot hole

[mvusse]

Most common cause of death wobble in my experience are issues with the track bar and the frame side track bar bracket. If neither of those are it there are 50 or so other possible causes.

 

If all else fails a heavy duty steering stabilizer can usually effectively mask it, but it doesn't fix whatever underlying issue you have.

[Eagle]

Most common cause of death wobble in my experience are issues with the track bar and the frame side track bar bracket. If neither of those are it there are 50 or so other possible causes.

 

If all else fails a heavy duty steering stabilizer can usually effectively mask it, but it doesn't fix whatever underlying issue you have.

And my experience has been that the most common cause of death wobble is tire balance, followed in a distant second place by insufficient caster angle in the front suspension.

[dasbulliwagen]

Most common cause of death wobble in my experience are issues with the track bar and the frame side track bar bracket. If neither of those are it there are 50 or so other possible causes.

 

If all else fails a heavy duty steering stabilizer can usually effectively mask it, but it doesn't fix whatever underlying issue you have.

And my experience has been that the most common cause of death wobble is tire balance, followed in a distant second place by insufficient caster angle in the front suspension.

 

I'm not sure I would say that those are the cause of DW. They are more like instigators of DW. There has to be other parts bad for these items to get DW started. Though these issues being good could make it so it never happens to begin with.

[Automan2164]

In my experience, it has always been the track bar, track bar bushing at the axle, track bar rod end, pitman arm, or loose steering box. Anything that will cause a skip/looseness in the steering to axle placement. If the axle can walk, as with a worn trackbar, every time it walks you get an undesired steering event. Same with worn steering components or gearbox... If one can move independently of the other, the wheels can wander left and right, until they catch just the right bump or speed and set off the whole works.

 

Have a buddy get in the truck, key on, engine off, and saw the steering wheel back and fourth with the wheels on the ground. As they are doing this, look for any looseness or movement in between rod ends, bushings, or components.

 

Rob

[cruiser54]

Possibly one of the best write-ups I've seen on DW:

 

 

 

 

 

 

 

My understanding of “death wobble” is this. Somewhere in the vehicle, one or more components is worn beyond tolerances, and when oscillation initiates from a suspension “traumatic” event (hitting a bump or a pothole) or also when a vibration reaches a certain point and harmonic at a certain speed, it causes theother components to react. This is called the “multiplier effect”, where one component affects one or more other components as the event travels through the front end of the vehicle.

 

 

 

Death wobble is not uncommon with the XJ. It is even more common with a lifted XJ. Finding the worn component or components is not always easy. It can sometimes be downright difficult. Sometimes it’s obvious. other times everything appears to be okay when you perform an inspection on a hoist, but getting the vehicle up in the air and going over everything with a fine tough comb is always a good first step. It is very helpful if you know exactly how to perform a comprehensive inspection of every single front end part, looking for abnormal wear and or play in that hardware. If you do not know how to do this type of inspection, pay an experienced professional to do it. Be sure to ask them if they are familiar with “death wobble”, as not all technicians are versed in this…..

 

 

 

Check out the below link if you would like some extensive reading on “death wobble” causes and cures. From my research, Kevin (the author of this tutorial) is possibly the best in the business with tracking down root cause of death wobble. He does offer hardware for sale that can help resolve death wobble, but even if you don’t buy any parts from him, you can still get some excellent ideas on what to look at in resolving your death wobble.

 

 

 

http://www.kevinsoffroad.com/how-to-fix ... th-wobble/

 

 

 

Possible causes of death wobble are listed below. Isolating death wobble is a process of elimination and the root cause is not always obvious and it can often be caused by a combination of things! From my personal experience, I would first concentrate on the track bar and the control arms and associated bushings.

 

--------------------------------------------------------

 

-Front tires out of balance (try swapping fronts to rear and see if symptoms change)

 

-Tire pressure. Don’t laugh. It’s not a root cause but can exaggerate the problem. Experiment with lower tire pressure to see if it helps

 

-Improper lug nut torque on wheels

-Front alignment out of spec

-Loose track bar

-Worn track bar bushings

-Worn track bar (check for play!!)

-Bad control arms and associated bushings

-Worn/damaged steering stabilizer (not generally a cause in and by itself)

-Worn/damaged shocks

-Worn/damaged tie rod end

-Bad U Joint

-Bad ball joint

-Loose frame mount

-Steering box loose

-Bad front hub assembly

 

 

 

 

 

Tom Walker

[35 Dollars]

If you really want to find out exactly what's wrong with your front end, take your MJ to a tire shop that does front end alignments, too. Tell them you just want a front end alignment. The technician will come back to you with a list of things that need to be fixed. Fix them, yourself! Then take it back to them for the alignment.

 

Ron

[JFAComanche6]

To check your tie rod ends, take a big breaker bar, brace it against something, and try to push down on the top of all your tie rod ends. If it depresses any, replace it.

[Eagle]

Most common cause of death wobble in my experience are issues with the track bar and the frame side track bar bracket. If neither of those are it there are 50 or so other possible causes.

 

If all else fails a heavy duty steering stabilizer can usually effectively mask it, but it doesn't fix whatever underlying issue you have.

And my experience has been that the most common cause of death wobble is tire balance, followed in a distant second place by insufficient caster angle in the front suspension.

 

I'm not sure I would say that those are the cause of DW. They are more like instigators of DW. There has to be other parts bad for these items to get DW started. Though these issues being good could make it so it never happens to begin with.

No, there don't have to be other bad parts. I have experienced genuine death wobble in two vehicles. One was my then-new 1999 Grand Cherokee WJ, with (at the time) probably just over 5,000 miles on it. Everything was stock, I never took it off-road, so everything in the front end was new and tight. The death wobble kicked in when I touched the brakes lightly to control my speed going down a long down grade at about 50 to 55 MPH. The front rotors were warped (very common on the '99 WJ), and the resulting wobble in the rotors was all it took.

 

The other was in my '88 Comanche -- after I had removed the lift and returned it to stock. Track bar was almost new, front hubs had been replaced, tie rod ends were tight. The DW kicked in at 50 MPH as I entered a long, sweeping right hand curve on a state highway. I turned around, limped home, rotated the front tires to the rear and the DW never happened again.

 

It's tire imbalance that is the fundamental cause of death wobble. Loose parts may (or may not) play a role in allowing it to escalate. On the other hand, when the original track bar on my '88 Cherokee wore out and got loose, it was winter and I had no garage to work in, so I drove it like that for about five months. I had at least a quarter turn of free play at the steering wheel, probably closer to a third of a turn ... but not a hint of death wobble. Not ever. So a loose track bar by itself CANNOT cause death wobble. I have five months of rolling evidence to support that statement.

[ParadiseMJ]

Does a 2 wheel drive even have a track bar?? I think not.

[HOrnbrod]

Does a 2 wheel drive even have a track bar?? I think not.

 

Most definitely. Same track bar as the 4WD. Only difference between 2WD and 4WD is the Tcase, diff in the middle of the beam, and axles. Still have to maintain the steering geometry in both.

[mvusse]

I have found a track bar with a tiny bit of play can allow DW to happen. A LOT of play can cause loose steering and the truck wandering all over your lane, but has too much movement to hit a harmonic with the steering.

[Eagle]

I have found a track bar with a tiny bit of play can allow DW to happen. A LOT of play can cause loose steering and the truck wandering all over your lane, but has too much movement to hit a harmonic with the steering.

Harmonic. This is the crux of the issue.

 

One wheel doing something screwy is either "shimmy" or "tramp," depending on what the wheel is doing. It doesn't pose a real problem (other than tire wear and beating up the tie rod end on that side) unless/until the shaking gets transferred to the opposite wheel and the two start shaking in unison, in a self-escalating harmonic.

 

In fact, Chrysler/Jeep had to change the spring rates and the hardness of the rubber bushings in the front suspension of the export models of the 1999 Grand Cherokee because the particular combination they originally chose resulted in death wobble. And this was with brand new vehicles.

 

All of which is to point out that there really isn't any one, single thing we can point to and say definitively "THIS IS IT!" It would be great if we could do that ... but we can't.