[Dennisr]

Hi,

Two years ago I added to my JK;
- Dynatrac axles (front with extra caster angle)
- Teraflex 4" lift (shortarm) with elka shocks
- 37" BFgoodrich Tires on 17" Mickey thompson wheels

I experienced bumpsteer and death wobble since then, so I;
- Had everything aligned (twice)
- searched the internet for the cause (planman's youtube movies etc.)
- added a high steer kit
- raised my trackbar
- played with different air settings in the tires
- changed the steering stabilizer
- Gave the wheels more toe out


My conclusion;
- Lowering the air in my tires helps, but with the 3.8 it makes the Jeep to slow.
- I think the angle (see pic) of my trackbar and draglink is correct
- As far as I know there is no play at the bushings or anything else
- the steering stabilizers makes sure death wobble doesn't occur, but it's still there. It only works as a bandage.
- The toe out on the wheels made the tires wear out excessivly

I know bumpsteer and death wobble are two seperate things, but I experience both in my JK.

Who can help me out fixing this, because there is no decent shop over here which can cure my problem.

I'm actually debating on putting a full hydro kit on my JK if I can't solve my problem.


Please help.

 

[Dennisr]

Try to get a picture that shows both ends of each the track bar and the drag link. Its hard to tell angles for sure without being able to see the drivers side end of either of them.

RK

Thanks guys for all the replies. A lot to read, hopefully some answers to solving my problem.

Here's a pic to shows the angles. They look pretty parallel to me.

 

[Dennisr]

I never saw you mention weight distribution. I fought it as well. Getting your track bar and drag link parallel is a big deal. When I did that (Teraflex frame side drop for the track bar) it helped a lot. The other piece of the puzzle for me was changing the weight distribution. I added some spacers in the front to level the ride and it made a world of difference. Keep in mind that your axles have to shift as your springs compress. If you have a heavy rig and are front heavy (weight distribution too much toward the front) then it will play havoc with steering. It amazed me how much 1 inch on the driver and 1.5 inches on the passenger did for my ride (leveled gas tank at 1/2 full).

Teraflex bumper front with winch, LOD rear bumper with no rear tire. The Jeep is level. I don't really think this cause the problem, but I could be wrong

 

[Dennisr]

Does your steering wheel actually move ?My light weight 2 door fights the road/ruts but steering wheel is still.

Do you or a friend have a Gopro ?
Mount to the front cross member and see what's going on. http://youtu.be/DGVbULgCP14



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Yes, it moves. It jumps to te left and right when I hit a puthole. When the Jeep hits a bump with both wheels simultaneously the steering wheels remains straight.

 

[Dennisr]

Why did you toe it out? How much?

It forces the wheels to drag a little over the road and therefore gives the wheels no chance to shimmy. The tires wear out to fast like this.

 

[Dennisr]

Judging by the pictures and the OP's posts, I think he's mistaking his problem for being bump steer when that's not the case.

That could be true. When I hit a bump or puthole my steeringwheel moves. When both wheels hit it simultenaously the steeringwheel doesn't move. I tought it was bumpsteer. What do you think it is?

 

[Dennisr]

I'm aware of the effects of toe, how much did you adjust it?

Can't remember. I tried several settings

 

[Dennisr]

That's just the wheel shimmying and the force being transferred through the steering. The steering stabilizer will try to dampen this force, but it can only do so much.

This is pretty normal for a vehicle like this, we don't have rack & pinion steering like cars and SUVs. This is not bump steer.

When I was doing research on the internet I came upon B.S. on steering stabilizers with a lifted vehicle. - YouTube video. His JK drives fine without the ss. He has different components, but I also have a teraflex adjustable trackbar. The tie rod is different though.

 

[Dennisr]

Drag link and TB look parallel. My question .... All that work. Is that a factory tie rod ?


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Correct, you think the stock tie rod would tribute to my shimmy?

 

[Dennisr]

Well if someone tells me they have bump steer I'm not going to be arrogant enough to tell them it can only be specifically caused by one thing. I'm going to understand that they are describing what happens when they hit a bump and start the diagnosis from there. If someone tells you when they hit a bump their JK changes lanes, how would you describe it?

Whose drag link flip / track bar setup did you add? As suggested, are they at the same, or near same angle from the pitman arm to the knuckle, and frame to axle? Are the bushings & TREs OK? Teraflex's approach is a bit differnt, in that they drop the track bar mount at the frame rather than raise at the axle. Not ideal but works fine. (Drag link & track bar are in different planes.) Please advise and we'll see if we can sort this out.

Well because I didn't expect to get all these replies (thanks for that). I paid extra attention this morning when I was in my JK.

Hitting a bump with my left or right tire will cause a pretty severe shimmy in my steeringwheel. Approx. 1-2 inch turn in the steeringwheel.

When hitting a bump with both wheels simultaneously it also causes a shimmy, but when holding the steering wheel it's nearly noticeable, only when I let go of the steering wheel.

There is a corner in a road over here where I do my death wobble testing. Every time I hit the put hole in that corner (steering left, hitting with right tire) everything start to shimmy pretty bad. I'm sure when I remove my ss, death wobble will occur.

All my components were brandnew added two years ago. The flip kit and teraflex track bar were added a year later. Total miles on axles, lift kit etc. Max. 10.000.

 

[Dennisr]

This weekend I'm planning on doing the full checkup again. Probably next week alignment.

I don't have a Gopro to film, but I'll find something.

Thanks for all the replies

 

[Dennisr]

I might of missed it but have you checked your ball joints yet?

Yes I did, but I'm going to check them again this weekend

 

[Dennisr]

If the OP has parallel planes of mounting points for the drag link and the trackbar and they are not at overly steep angles, he doesn't have what is defined as Bumpsteer.

Because he describes conditions of death wobble, if his alignment specs (caster, camber and toe) are within spec, the source(s) of his problems are those that relate to death wobble.

Factory ball joints can fail very quickly if there are other problems going on.

Factory bushings can fail fairly quickly if there are other problems going on and/or if suspension bolts (control arms and trackbars) were not torqued at the new ride height after a suspension install.

For non-flex joint control arm and trackbar ends, all bolts absolutely must be loosened for a suspension install, and no control arm or trackbar bolts should be torqued until the full weight of the vehicle is on the ground at the new ride height, with the bushings in a neutral position.

The rubber Clevite bushings are so soft that if pre-loaded/twisted/binding to a different position than actual ride height, they will fail prematurely. The bushing bolt sleeve will prematurely separate from the rubber bushing. This is especially a problem with the front upper axle side control arm bushings.

Until they fail prematurely, these pre-loaded/twisted/binding rubber bushings that are pinched in between the brackets at the wrong ride height will result in a jittery ride.

The thorough way to inspect the bushings is to (one at a time) remove the control arm or trackbar, inspect for cracking or separation visually, and to insert a long screwdriver or ratchet extension through the bushing bolt sleeve and flex the bushing to inspect visually for separation or cracking under misalignment.

The control arms and everything else were torqued when the Jeep was on the ground. I'm aware of the situation you describe above.

Can someone give me the correct alignment specs? Toe in, caster, etc. I assume everything should be the same as the factory specs, except for the caster?

 

[Dennisr]

Did you have install the Teraflex drop track bar from the frame (part if the 4 inch lift) and then add a flipped kit which raises the tracbar mount from the frame also??????


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No, I raised it on the axle side.