dome light!!!!!!!! this is way too funny!!!!!!!!!!!!

 

okay, let me rephrase, a tire can be out of balance to the point it is not safe to drive on.

but normally a tire will give you warnings.. like a slight shimmy while rolling. or a wobble that gets worse the faster you drive..

The DW i have dealt with, was not "Gradual" or... didnt give you a warning. you simply went from bobbing your head to a good song, to... needing some toilet paper and a change of shorts..

 

You forgot about steering box. If the steering box is worn and there's 2-3" of play in it then you'll get your tires wobbling left and right (DW) and it's no fun. Ask me how i know. But i do agree that most cases are a result of a bad trackbar bushing/rod end.

 

Alright guys sorry I was a little busy, as for the after market stuff I cant tell you exactly what is what as her parents had the lift kit put on a few years back and they dont remember what anything was either. the aftermarket control arms have poly bushings I think the track bar is OEM, Ill go under there and have a look today while she moves the steering back and forth-Thanks for the pointers

 

Before someone goes out and buys a track bar to go get an alignment first (unless you know it is worn out) , plus the alignment guy might spot something else you may need to fix before you hit up the parts house. in my case i had replaced everything before getting an alignment before the Death Wobblin whent away, * caster was way out of spec. -

 

Ok heres some pictures of the set up

 

I had a 93 cherokee and around 40- 55 mph it would wobble bad. I did a brake job, new shocks, motor mounts, and new bushings in front end. It didnt fix it. I eventually bought a new steering stabilizer ($30) and that was the problem.

 

a steering stabilizer is more of a silencer, the problem still exists its just covering it up.

I went out and measured between the front wheels to the rear, the drivers side is 70 and 3/4 inches and the passenger is a hair over 70"...so wtf

the track bar has a small amount of play and so does the drag link. the bushings on the shocks are pretty shot, the passenger one is a little looser than the drivers side on the bottom. the entire axle moves when you turn it side to side, not a lot but Im pretty sure the track bars are not doing their job

 

Okok, i think everybody is right in this thread.
I think there is no real solution for the DW problem at the moment.
I must say something about the engineering explanation (and would like to see some numbers the next time, I am one too!).
I don't agree very much with the increased tire dimension amplifying the wobble.
I have personally experimented switching back to the stock tires, and the DW increased a lot.
My explanation to this is that bigger tires means also more weight and therefore more inertial mass that needs to be accelerated back and forth.
This gives us a lower frequency of the vibrational motion and therefore less wobble.
All this does not solve the problem though, basically we need to find out something to do to our suspesion that avoids the vibrational motion to resonate with the damping function, and it has something to do with the reaction time of the damping system.
The damping action must occour when the oscillating motion is at its highest intensity (the peak in the sinusoid) corresponding to the highest acceleration of the motion.
Unfortunately the steering damper is mostly effective in the linear part of the sinusoid, corresponding to the biggest shift but acceleration equal to 0.
Overdamping the system or stiffening the suspension will only postpone the problem.

 

so.. lifted with the stock Trac bar you say?

There's your problem.

honestly. that is your problem. any amount of lift requires Trac bar work. 2" requires you to re-drill it over about 1/2"

3" lift requires an adjustable.

5+ lift requires a Trac bar and bracket Like Rubicon express's style.

Sounds like your at ATLEAST 4" of lift upfront, that is completely unacceptable with the Stock OEM trac bar.

(sorry for sounding rude. but the "Guesses" will have you spending money that dont need to be spent. buy an adjustable trac bar. install it, get an alignment. and your set)

 

People kept telling me my jeep will DW badly if I lift it up as much as I did. With 6 1/2" lift and 33" mud tires people said it will shake badly... Polyurathane bushing help a lot in the arms rubber is to hard. I have an extra swing arm connected to my front axle with the extended arms that are there stock but of course they are longer due to the lift kit. but and upgraded steering pump and upgraded steering control arm (adjustable arm). If you lifted it 3.5" did you get the entire set with the lift kit. I have a rancho 6 1/2" lift kit and it is the entire kit. and with better bushings and adjusting the steering arm just right I don't have DW at all.

 

This is interesting... Since this is the first thing we have found that may shed some light on the issue let's focus on this. OK, he has 2 different measurements on a fore aft measurement. That would lead us to believe that it is not the trac bar since that would be a side-to-side issue. What controls the fore-aft axel position? Answer: The control arms and bushings do. Anything else control for-aft that anyone can think of? Maybe an accident on the passenger side? Not likely since he already looked for damage... (Hopefully the skid guard was taken off while looking).
So, in my mind the first thing I would compare is the passenger to driver control arm. Looking for damage or a bent condition. Then I would loosen up the bolt holding the front bushing on the passenger lower control arm. Jack it up and move the axel fore aft to see if it has play. Better yet, take the front of the lower control arm off and inspect the bushing. If that looks good take the back of that control arm off also. Inspect that bushing and let us know what they look like.
Mike

 

He already has an adjustable track bar, u can see the adjusting nut in one picture and the bar parallel to the axle tube in another.
Honestly, even if it was a non worn out stock track bar the worst thing that could happen is to shift the axle an inch or two to the left.

 

My head hurts from all this "advice"



And people want to know why I got into advanced tech/fab.


Before you do ANYTHING else .... remove the skid to make it easier to see WTH is going on.



The first area I would start with is the heim joint at the frame end of the track bar. Ensure the jam nut is tight. Then have someone move the wheel back/forth (key on, but engine off) and look for movement in the joint itself (at the ball). Double check the bolt going thru the track bar bracket as well. And take the time to check the bracket-to-frame bolts.


If all is tight there, then check the bushing at the axle end. Often, the hard polyurethane will get "wallowed" out by the steel sleeve that the bolt passes thru. Make sure the bolt here is tight too. If these 3 things check out good .... you have eliminated the track bar.


After that .... have your assistant (hopefully a good looking girl/woman) continue to cycle the steering wheel left to right. Check your tie rod end on the pitman arm to see if it's moving/popping around. Then check the other end of the drag link at the knuckle. A good lever will help you here as well. You should be able to pry (gently) and not see the TRE body attempting to pop off the stud. Check the tie rod ends on both sides of the tie rod (draglink & driver side knuckle).


If those continue to check out good ... the next area of inspection should be your balljoints & unit bearings. The vehicle will need to be up in the air or on jackstands for this. Grab the wheel at 12 & 6 o'clock position and pull/push respectively in an attempt to force movement. Meaning push at 12 and pull at 6 (or vice versa). Any movement at all means something is worn. Have your assistant look at the balljoints while you attempt create movement. If you can see movement on either the upper or lower balljoint ... you've got it covered. If you are unable to see any kind of movement ... the unit bearing may be suspect.



Once you have done and checked all these things .... THEN it's time to get an alignment. I like to see 1/8" (or less) of toe in. Your caster should be between 5 & 7 degrees. Do not let the monkey at the alignment shop tell you that caster is not adjustable. Show him the LCA bracket at the frame and point out the 2 bolts that have shims wedged in there. That's your caster adjustment. The LCA bracket is slotted where the bolt is -- to allow for adjustment. If you have adjustable control arms --- Even better! Camber will only be adjustable thru specialty replacement balljoints (and would not create the issue you are having here anyways).



By this point ... you should have greatly reduced or eliminated any major steering imperfections.


There is 1 last possibility to consider ... however, it does not fall under "death wobble." And that would be bump-steer. Bump steer is road induced steering input. Meaning a bump will force the wheel to jerk in your hands. It won't produce a wobble ... but will give you more of a slalom effect in your steering. A simple way to tell how much you have ... is to turn the ignition on (no starting) and get the heaviest person you can find to jump on the bumper. Do not ask your mother-in-law to do this .... she may hit you with her broom. At any rate, see how much your steering wheel moves back and forth as the body goes up or down. It really should be an imperceptbile movement. I've had vehicles here that moved almost 1/2 turn each way when the suspension loads or unloads. If you suspect you may have this issue ... you need to verify your steering vs. track bar angle. One simple way is to take a picture of the front end and put it on the computer. Then open the picture in MS Paint and draw a straight line from end to end (or joint to joint) or whatever. Both lines should be parallel to each other or dang near close. Another way is to get a yard stick and an angle finder. Run it at a straight line and check your numbers. You want to see the same degree of angle each time. Do not concern yourself with the bends in either your draglink or track bar. It's the point-to-point angle that matters. If they are off, the simplest correction is a different pitman arm. More or less drop will change your draglink angle so that it's matching your track bar.



Other steering considerations that do not fall into "wobble" or bumpsteer catagories include: Worn out steering box, loose steering box bolts, worn out steering shaft ujoints, and worn front axle shaft ujoints. None of these will produce a wobble or bumpsteer problem -- however, they should be checked in order to have a properly responding steering system. All will contribute to a vague response or extra steering input (proportionate to how much the tires/wheels actually move. I am purposefully not including crossover steering quirks (dead spots) as that is more of an advanced issue that many beginner Jeepers may not see.


After all this is done ... THEN you may consider replacing your steering stabilizer. In a very loose sense .. the stabilizer is there to help smooth out steering issues as parts slowly wear out. They are not meant to correct any issues due to outright malfunction. I have said this here on CF before ... a properly designed & functioning steering system does not need a stabilizer.



My fingers are tired now ......



Joe

 

Endless Mountain Fab:
How do you explain the difference in the fore-aft measurements between the wheels? I can tell you this... It did not come from the factory like that? Since that is the first good piece of data he has given us shouldn't we start our investigation there? Or at least on things that would cause that? As I said earlier... hopefully he has taken the skid plate off during his inspection. If not he should plan on taking it to someone with check book in hand I think.
Mike