DW, no one knows why? What the hell!!

DaffyXJ said:
Jelly,
You said you researched all you could find about DW. If that's so you should know DW is ALL About the geometry. DW is caused by the resonant frequency of vibration in the front end components. When designed, the angles of caster, camber, tie rods etc are figured in to minimize Fo [read F sub O] (Resonent Frequency).
That's why there is a steering stabilizer on your Jeep. To absorb vibrations before sending components (even ball joints) into resonent frequency.
When we lift our vehicles, the one constant, independent of lift size, is we change the geometry of the steering components in relation to the other components.
So start looking at what you have not changed as opposed to what you have changed. Perhaps a longer track bar, or drop the pitman arm, or even make sure the disk brake rotors aren't warped are places to start.

Daffy, you are on my page Man. I still have a feeling that it is geometry!! 100%. Thanks for your input.

Jelly
Click to expand...
 
Gentlemen....here it is. I think Daffy is very much on track. Like I posted earlier, I said I started looking at the differences between pre and post lift. What changes, and what stays the same? I really am narrowing it down to the track bar being TOO LONG. I agree with a lot of you that the "slop" in the stock components help in building the DW and letting in worsen. However, I believe the root cause is the axle not being centered under the truck due to the shorter track bar. Thus, all of the other suspension/steering components that "want to be centered" are fighting the track bar which is pulling the axle off center. This is the kink in the intended geometry. All the rest just let it get worse. Once you hit a bump at speed the tires "lift" just enough to lighten the suspension and let it try to "come back to center" then the track bar pulls it back off center...etc. etc....and around it goes. I am planning to drop the coin for an adjustable bar from Kevin's, and try to get it back on center so it stops the dog-tracking/fighting itself. We will see.

PS Thank you very much to the few of you who offered sound ideas and good interaction of ideas.
 
Jelly...

Im no Professional Jeep mech, but every time I have encountered the "DW" it has always been my track bar, either the bolt loose, or the bushing worn out. You are on the right track with the geometry. I also agree with some of what you are saying about people "advising" you to change this part and that part. I prefer to properly diagnos the problem than throw parts at it. Yes Death Wobble can be caused by just about everything on your front end from bushings to loose control arm bolts. I also understand the frustration of experiencing these problems after only installing a 2" lift.

I am only suggesting to go back to the basics....recheck all your bolts on the front end and make sure everything is tight. Especially the track bar, since the stock one is only a tie rod end with a bolt on the other. It entirely possible for the trac bar to be bad at 30k, I have seen this on some grand cherokees.

Good luck.......

Scott.
 
Jelly Role said:
I am planning to drop the coin for an adjustable bar from Kevin's, and try to get it back on center so it stops the dog-tracking/fighting itself. QUOTE]

Lots of 3" kits and budget boosts recommend redrilling the track bar mount on the axle end 3/4" on center over toward the driver's side. On my first lift ever this was what the directions told me to do. Of course I recommend getting yourself an adjustable track bar, but for now if you want to address it immediately, drill yourself a new hole 3/4" over to the driver's side. It won't put you in a dangerous position. I drove on that setup for a couple of years before building a new track bar to replace it. I also wheeled pretty heavy and the ends wore out with no damage to the axle-end mount. Should work just fine for a 2" bb.
Click to expand...
 
Island,

Thank you very much. Is there enough strength in the stock bracket to alow for two holes? If i get the new one later(adjustable) does the stock bracket offer enough support to go back to the original hole? Thanks again!!
 
Island-

What if I loosened the bar, and remove the axle end. Then with a buddy helping, shake the truck side to side to let it center itself. Where ever the bar wants to be naturally, drill my new mount hole? Sound logical?
 
Jelly Role said:
Island,

Thank you very much. Is there enough strength in the stock bracket to alow for two holes? If i get the new one later(adjustable) does the stock bracket offer enough support to go back to the original hole? Thanks again!!
Click to expand...

yes there is definitely strength in the stock bracket to allow two holes. Its not ideal by any means, but I would be very surprised if anything adverse happened. When i made a new track bar, I put it back in the original hole and left the new hole i drilled as is. I did not get around to filling it up with weldbead for over a year. It never bent, twisted or became an oval hole, and like i said, i wheeled it pretty hard. Without offering any guarantees, I say try it out, it may solve your problems immediately, and if there is a problem, it would be nothing for your local welding shop to weld a new plate over the holes, and redrill out the original hole. At least this way you might get some immediate results.
Good luck.
 
Jelly Role said:
Island-

What if I loosened the bar, and remove the axle end. Then with a buddy helping, shake the truck side to side to let it center itself. Where ever the bar wants to be naturally, drill my new mount hole? Sound logical?
Click to expand...


you can do this, but the natural hole will probably line up closer to the old hole than the 3/4" i am recommending. I would not want to see them too close, or there will not be enough metal between the holes to have good strength. You might want to get in there and just check it out, if you feel good about it, give it a try.
 
I was thinking about this thread earlier and started thinking about other possibilities, which leads me to this...

When you did your lift, did you end up removing the control arms to get the coil spacers in? If so, what procedure did you follow to tighten the LCA bolts, and how tight did you tighten them?

When I do anything involving removing the LCA's, I check and double-check to make sure I get them tight. What I do is this: with the jeep all jacked up, put the CA in and get both bolts in, and put the nuts on the bolts just to where I can't turn them anymore with my fingers and leave them that way and re-assemble everything and lower the jeep onto the ground. Once it's there, I use the impact gun and a deep 21mm socket to get those things nice and tight. I've had them come loose on me when I just used a ratchet to tighten them.

I've had loose LCA bolts cause some wierd handling and shimmying on the highway, luckily I caught it before it was a huge problem. Luckily the nuts on the LCA and UCA bolts are self-locking, so they won't ever get loose enough to fall off and let the control arm fall out, but it could cause some shimmying if they're loose.
 
Jelly... do you think you could post a picture of the front underside of your jeep, straight on, so I can see the track bar and the drag link? I'm just curious and I want to compare it to mine, because I have a 2" lift as well, using the stock track bar in the stock location with stock steering. The only thing I did on mine was shim the LCA's a little bit too, and I'm riding smooth.
 
The only case of true death wobble I have experienced was in a completely stock 1999 Grand Wagoneer that had approximately 10,000 mostly highway miles on the odometer and had never been off road. And it only happened once, when I touched the brakes to maintain the speed limit down a long grade on a secondary road in New Hampshire.

Alignment was good, wheel balance had always seemed good, no worn components. The brake rotors were warped, and the light touch on the brakes was enough to set it off. However, the rotors had been warped for a couple of thousand miles and had never set off DW before, not did it ever occur again (at least while I owned the vehicle).

There's a very simple reason why nobody has posted THE ONE TRUE CURE for death wobble: There's no one cause. I'm the guy who tends to look first and foremost at tire balance, but sometimes it's tire balance plus something else.
 
I've had this same problem for about 6 months. My Rust's adj. trac bar TRE went bad. I replaced that. Still have it at around 50-55 mph. Alignment guy said TRE's are in good shape. Steering damper seems to be ok. Here is the real bummer... My pass. side front tire is wearing evenly much faster than the driver side. Also, the wobble/vibration is more noticable while accelerating up an incline between 50-55 mph. And again noticable while turning right only at those speeds while driving thru a long right hand curve. No vibes at all at 60+ mph.
I'm setting at 4.5" on a '92 XJ. I first purchased some LCA's for a 3" lift. After installing to a 4.5" lift, i had no problems. But that doesn't mean anything. I did find out that my sway bar is bent. Don't know if that would be a problem or not. But anything is possible. I just want to find out why only the pass. side wobbles or vibrates. I have new bearings and seals on both sides. Alignment guy said he thinks maybe an axle joint is froze up some, causing it to wobble while turning a slight right turn at those speeds. It sounds good, but why would it be doing it while level or an incline at those speeds? All of this DW thing is very difficult to figure out. So, i'm just going to start replacing everything as i get the $. After i fix that i'll buy new tires. Death wobble questions are worth a million dollars if someone could pinpoint a problem. Maybe someday myself or someone could find this out and retire early.
Cheers
 
Thanks everyone for the informative exchanges. I learned a couple of possible reason why my 2001 XJ had occasional DW, even when stock and is now much worse at 2 1/12" of lift. I will be replacing the CA bushing ASAP or better still with adjustable LCs.
I know the rig will be begging to be raised more at some point, so it will be money well spent.

Beats me how people can get so fired up over nothing but words.
Jelly doesn't deserve to own a Jeep with that kind of attitude, he's more of a Ford man.
Maybe he should visit Pirate4X4 for a real dose of down home friendliness and advice. I’m sure they would straightened him up right away
 
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