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Unread 09-10-2013, 03:57 PM   #1
poke_53
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1999 XJ Cherokee 
 
Join Date: Sep 2013
Location: Conway, AR
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Death Wobble?

I figure this has been discussed quite a bit and I have read a lot. Here is what I have:

My father purchased a 99 XJ for me last week and we met for delivery of the vehicle. This Jeep has a 2" lift front and rear with 31-10.50X15's. He drove it for about two hours to get it to me. On my way home (1.5hrs) I experienced the dreaded death wobble 4 times. Twice at 70MPH and twice at about 55-60. I have an appointment on Saturday for an inspection of my front end by a local shop. I have read that a lot of the cases are solved by replacing the Trac bar but I also understand that it could be several other issues. My question to you guys is:

What all should I tell the shop to inspect/look at in order to get a good assessment to my problem.

Also, I love it so far but the wobble almost made me POO myself.

Thanks in advance


Last edited by poke_53; 09-11-2013 at 10:07 AM..
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Unread 09-10-2013, 04:10 PM   #2
tjwalker
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Welcome to the "death wobble club".....admission is free!

On my 99, my death wobble was caused by the track bar. You are correct in that it is a component to inspect very carefully, even the SMALLEST bit of play in the track bar can lead to death wobble. But there are lots of other causes too. Here is more on DW.

Good luck and keep us posted!
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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 the other 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. Have a friend turn the steering wheel back and forth full travel as you perform the inspection. 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-...-death-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.
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-Front tires out of balance (try swapping fronts to rear; 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
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Unread 09-10-2013, 09:33 PM   #3
poke_53
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Thanks for the information. The shop I am taking it too was not aware of the term Death Wobble but they stated they were familiar with Jeeps and they do a lot of front end work. I will do more research and see if I can find a shop that knows what the death wobble is.

Thanks
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Unread 09-11-2013, 05:20 AM   #4
dave564
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Quote:
Originally Posted by poke_53 View Post
Thanks for the information. The shop I am taking it too was not aware of the term Death Wobble but they stated they were familiar with Jeeps and they do a lot of front end work. I will do more research and see if I can find a shop that knows what the death wobble is.

Thanks
If a shop told me that they do a lot of front end work on Jeeps, and don't know the term death wobble, I would go somewhere else.

(Assuming this XJ is stock, as in no lift) Might I suggest going to the Jeep dealer directly, at least for the diagnosis. They WILL know what death wobble is, and what to look for.
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Unread 09-11-2013, 10:08 AM   #5
poke_53
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Sorry I edited the original post. 2" lift with 31-10.50x15
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Unread 09-11-2013, 10:29 AM   #6
foggybottombob
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The technical term for death wobble is shimmy. So I would expect a shop to know what shimmy is.
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Unread 09-11-2013, 10:47 AM   #7
Sykes
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I have it around 55 mph with the jeep hitting a vibration resonance. Mud on the rims can start it. An online video (bleepinjeep) on DW said that a loose hub can cause this to, beyond all the obvious bushings, control arm, track bar problems.

I have a hub that can shift/shimmy a bit when I take off the tire. If this is a bad hub, sounds like a rough fix. Strangely my death wobble began the day I bought four new AT tires which I had balanced several times, to no change. They have been great on/off road tires for the last two years, but with the shakes. Probably just a coincidence the problem started with the tires, but the day I drove off from the shop, felt like the car was going to shake to pieces on the freeway. Used to it now and it's less when the mud is off the rims.
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Unread 09-11-2013, 11:32 AM   #8
poke_53
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Good News. I have found a local shop that has dealt with DW in Jeeps and Dodge truck. I will see what they say.
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Unread 09-12-2013, 10:24 AM   #9
poke_53
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OK got word from the shop. They said I need to replace the Trac Bar and the Lower control arms. Another question for you guys. This Jeep has a 2" lift and 31-10.50x15 tires and I am going to get an alignment as well. Will someone please share what specs I should tell the alignment shop that I want considering it is lifted and it has larger tires.

Thanks
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Unread 09-12-2013, 11:20 AM   #10
foggybottombob
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For 31" tires you don't have to move from factory alignment specs. But the rule for big tires and lift in general is minimum caster and maximum toe in. I have a 4.5" lift with 31" tires and use 1/8" for toe in. I do the adjustment myself in the drive way and that has worked fine for me.
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Unread 09-12-2013, 02:48 PM   #11
accelr8
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From what I understand, toe-in should ideally be around 0.25 degrees, and setting this by using a measuring tape will depend on where you measure. Arc length is a function of radius and angle, so if you measure at the rim edge the toe-in distance between the inside of the rims will be smaller than if you measure at the outside edge of large tires. I did the math and if you're measuring at the edge of a 15" rim, 0.25 degree toe-in comes out to 0.12" which is between 1/16-1/8", but if you're measuring at the outside of 31" tires it will be greater at around 1/4" for the same toe-in. I doubt 1/8" to 1/4" makes a big difference though.
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Unread 09-12-2013, 04:35 PM   #12
poke_53
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So are factory settings going to be fine
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