Death? Wobble

[Aaron]

Hey all,

I have an issue with the JK I wanted to throw at you all. I have an oscillation that happens in the steering of the JK if you were to hit a bump right between 23 and 33 MPH. People get all freaky about what you call death wobble and not death wobble so I am hesitating. However, this wobble, once started, will not stop unless you get out of that speed range and the vehicle is pretty much not steerable.

I have read many articles and the issues is mostly caused by issues with the track bar or with not loosening the bolts on the control arms and/or track bar when lifting your vehicle. I had done all those things when I lifted the vehicle, however, I did them again to make sure there was no binding. Some people say put on a stiffer stableizer or adjust the caster. Most people say these are things which just mask the problem by tightening up the steering.

I have a theory but I am not sure... Take a look at the pictures below. This is one of my front lower control arms mounting points (yes the other is the same). Notice that the rubber bushing does not extend all the way to the edge of the mount. The stock ones did. So, between the mount arms (?) is the sleeve. Since the sleeve has the rubber bushing between it and the actual control arm, couldn't this cause a side to side oscillation that could end up being death wobble? Or are these bushings too stiff to allow such things?

[Aaron]

One other thing I just noticed in the pictures...There is a place where mud has been rubbed off in that top picture. I just went an looked at all the other mounts. There is no such rubbing going on. This leads me to believe that this CA bushing is allowing the control arm to move back and forth? Would you all agree?

[Hypoid]

If the sleeves are clamped tight in the frame bracket, check the bushings for wear and tear. Are these Poly bushings?

Correcting the castor is not a band-aid because lifting changes that angle from stock. When I first did my BB, the steering would "hunt" every time I hit an expansion joint on the highway. Also, the steering would not re-center on it's own.

[Aaron]

These are new control arms from the lift so the caster was changed when lifted and the steering does auto center very well. see the picture for the difference in the length of the lower control arm. In the picture, the other end of the control arm is resting with the mounting bolt in the mounting hole so the comparison is close. This was a 3.5" lift.

Its hard to tell from the picture but the new control arm (round) is about 1/4 to 3/8 inch longer than the stock one (square). Also notice the rubber bushings on the stock control arm go all the way to the edge of the sleeve which would not allow as much side to side motion? I think this might be where the issues is. Opinions welcome!

[Brad]

You should have no lateral movement in that arm. Any stress is going to lead to excess wear on the Bolt/Arm. Seeing as you not only have a lift but bigger Tires putting extra stress on the suspension I would see if someone has come up with a remedy. Possibly on a Jeep forum.

[MelloYello]

How does your track bar look? Is it the stock one or did your lift come with that too? If it is stock, I would look in to a HD replacement. On my XJ, I had the wobble around 45-55 mph, I replaced the stock track bar with a JKS Heavy Duty one and it has not wobbled since. ??

[scout man]

I would say yes, that gap should not be there (as least not as large). As a way to see if that is the problem, I would suggest putting one or more large washers in that gap (large enough to cover the whole bushing and then some) and see if that fixes the wobble. If not, then that was not the problem!

[Jackie]

Check out this forum iif you haven't already) and do a search for "death wobble". There are many, MANY comments/solutions for it: http://www.jeepforum.com/forum/f96/

[Hypoid]

First, a rubber bushing is bonded to the collar, a polyurethane bushing is not, and will have lateral movement if not captured. This has been touched upon by a few of the respondents to this thread. What are these bushings made of?

Second, what brand kit is this? Are there reviews on any JK specific forums?

The first and second questions may bring us to an Ahh-ha!!! moment.

Third, I've seen some baddass home built Johnny joint/flex joint arms that use the rebuildable joint at the body mount. I'll bet S&P Customs could weld some on your existing arms.

[Aaron]

Here's what I think my plan of action is. I'd like to get new adjustable control arms but the funds won't allow it right now. I checked my caster and it is roughly at 7 degrees which is at the high end of factory spec. Everything I've read says that with larger tires, the caster is better at a lower 3 or 4 degrees. The lower the caster, the less chance of wobble. Since my stock control arms are shorter than my new ones, I'm going to put the old ones back on and see what happens.

I am going to remove the track bar this weekend to make sure the bracket and or the mounting holes are all still good. I'm going to rotate the tires again.

Lastly, I know its a mask, but since my wobble is relatively minor (slow speeds, not a death trap) I think I'm going to find a stiffer steering stableizer to help out as well.

[Aaron]

Hypoid previously posted:

[Aaron]

Jackie previously posted:

[Aaron]

I'm also going to be checking the ball joints on the passenger side as well. I've noticed that I can sometimes create the wobble just by making a sharp left turn. I'll rotate that tire out as well and see what that accomplishes.

[Aaron]

NCB previously posted:

[scout man]

those tires are brand new right? I cant imaging those are causing your problem unless they are REALLY out of balance. Im still sticking to the easy test first - just throw some washers in there and see what it does!

[Hypoid]

Aaron previously posted: