Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login

Posted: 10/12/2007 6:58:53 AM EST
Here's the deal. I've got an 89 YJ that has what is commonly described in the Jeep community as a "Death Wobble". Here's what happens:

At speeds over 55-60mph, *sometimes* (it's not often) the Jeep begins to VIOLENTLY shake. It doesn't happen all the time, and I can't make it happen on purpose. And when I say violently shake, I mean it. I lose control of the Jeep. If I slow down to about 45 it goes away. I can then resume my 60mph cruising speed and everything is fine - but it "feels" like it wants to happen again.

It's scary as hell when it happens, and if it does it to me this winter, it's going to mean an accident.

Observations and notes:

1. The suspension is bone stock. No lift.

2. The stabilizer link bushings have been replaced (suggestion from another guy), and they were obviously shot to hell anyway. Problem still exists.

3. The alignment has not been checked, but it tracks perfectly straight if I let go of the steering wheel. It doesn't pull to either side.

4. You can "feel" it beginning to happen. It occurs mostly at speeds above 55, and on roads that aren't glass smooth. When you hit a bump, you can feel the oscillations beginning (it's particularly noticeable in the steering wheel). If you accelerate during this "pre-death wobble" period, it will surely set the process in motion and the Jeep will begin to shake violently (it's so bad, you can't even see out the window).

5. If you feel it coming on and decelerate, it goes away. You may then resume the speed you were just at and it'll be fine. For a while.

6. It seems more likely to occur if you hit a quick succession of small bumps or imperfections in the road. Interestingly, flying over railroad tracks (a REALLY good bump) won't do it. I've tried - over and over.

7. My dad has seen a Jeep do this while driving down the Ohio Turnpike (I-80). The front tires were jumping up and down, and the driver had a difficult time keeping the vehicle on the road until he slowed down. Just like me, he resumed his speed (passed my dad) and all was fine.

8. The steering wheel doesn't move back and forth. It's just easy to feel the oscillations beginning through it. The shaking is a violent up/down motion.



Listen, I need to get this fixed or I can't drive it in the winter. It's one thing for this to occur on dry pavement. It's quite another for it to happen in the snow. If this happens in the snow and ice, I will probably roll the Jeep or crash it into something at the very least. It's unsafe, and that's an understatement.

I've asked this on Jeep boards before, and I can't get any definitive answers. Everybody that replies says "I had this happen to me" or "My friend's Jeep did this and here's what I did...". That's all well and good, but when I add all the suggestions up, I also end up with a brand new suspension by default. I can't afford to chase it down that way. I need REASONED answerers, and I need them from people who understand suspension geometry. I turn to arfcom, because we really do have some exceptionally bright and talented people here.

If you tell me "maybe it's the ball joints", I need to know how to verify this DEFINITIVELY without putting new ones in first. If you tell me "check the tie rod ends", I need to know how to do this DEFINITIVELY without purchasing new ones (and having the vehicle realigned again). Basically, I can't afford to just start swapping parts until the problem goes away. I know that will work, but I don't have the money or the time to approach it this way. I don't have a garage or even a paved driveway to work on this thing, so doing suspension work is VERY troublesome and difficult.

I need this pinned down, and I need it backed up with rational thought. I can't be outside in the cold lying on a dirt driveway for a month chasing dead ends.
Link Posted: 10/12/2007 7:04:03 AM EST
I recommend cutting a hole in the driver's seat, so that at least when it scares the shit out of the driver, it has someplace to go.

It sounds to me like a careful examination of the springs and shocks might be in order. There's some harmonic dischord being set up in the chassis that the suspension is unable to dampen. Jeeps are really light vehicles.

Tagged for future knowledgeable sources.
Link Posted: 10/12/2007 7:06:18 AM EST
Like a few of us said in the other thread...

The cheapest place to start is checking your tires. Make sure they are balanced well and wearing evenly. Rotate them see what happens.

Second, I know you don't have a lift, but on TJ's a lot of people do a t-case drop to relieve wobble. This is also a very cheap thing to try.

From another jeep website...

Q: What is a Transfer Case (T-case) drop?

A: A transfer case drop does just what it says. It lowers the transfer case skid plate. It is done with either spacers or washers placed between the frame and transfer case skid plate. It is used to reduce or stop vibrations from the rear driveshaft due to a suspension lift. It has the same effect as a MM lift by getting the driveshaft in line, but you loose some ground clearance when you do it. This is the cheapest way to stop driveshaft vibrations caused by lifting your Jeep.



Link Posted: 10/12/2007 7:06:41 AM EST
Bent or out of balance drive shaft, or a bad U-joint.... Those would be my two best guesses.
Link Posted: 10/12/2007 7:06:50 AM EST
Check the tires. My XJ was doing that until I replaced all four tires. The front ones were shot and out of round.

Replace the steering stabilizer with a heavier one, but this only treats the symptoms, not the cause.

Look for anything worn or loose on the steering and front suspension.

Good luck.
Link Posted: 10/12/2007 7:08:41 AM EST
[Last Edit: 10/12/2007 7:10:11 AM EST by Subnet]

Originally Posted By KimberTLE45:
Bent or out of balance drive shaft, or a bad U-joint.... Those would be my two best guesses.


New shafts (both balanced as well), and I replaced every U-joint on the vehicle (6 of them). No dice.

I've also driven in vehicles with bad U-joints, and they don't behave as described.
Link Posted: 10/12/2007 7:11:01 AM EST

Originally Posted By Vaquero45:
Like a few of us said in the other thread...

The cheapest place to start is checking your tires. Make sure they are balanced well and wearing evenly. Rotate them see what happens.

snip


check your tires. There's absolutely no reason to start spulling suspension parts.

Rotate and balance them. If you haven't done this, I'd damn near guarantee that's your problem.

Link Posted: 10/12/2007 7:11:26 AM EST
[Last Edit: 10/12/2007 7:18:27 AM EST by Redec]
Cap off the headlight fluid?.....

Umm, do you feel it start in any one place like the front passenger side? If you do rotate your tires. When a tire or wheel is way out of balance it will cause a violent shake.

Has any of your tires been plugged? I had to put a tube in my tire because I puntured the side wall. I also patch the side wall. This caused it to be off balance and after a few months my car started jumping almost. Sounded like the damn wheel was going to pop off. Mud on the inside of the wheel will casue this too.

Other than this your getting into you suspension. And unless you take it to someone, its hit or miss. And taking to so someone is no guarantee.

If you cannot tell if its comming from one side or another, front or back, I might check out your motor mounts, I have had bearings go out in the transmission, engine and the courrier(spelling) and it never caused my car to shake.
Link Posted: 10/12/2007 7:11:48 AM EST
ya maybe a blown belt or something in a tire... or even a set of new shocks in the front or maybe bushings on the sway bar are way blown out.

dw is your axel shifting left to right which should not be possible with a track bar that is close to parallel with the axel... i think

check the track bar and make sure it is aligned and all the bushings looks good, maybe that bar is bent or something
Link Posted: 10/12/2007 7:14:22 AM EST

Originally Posted By Subnet:

....

At speeds over 55-60mph, *sometimes* (it's not often) the Jeep begins to VIOLENTLY shake

....




I suggest, get the wheels checked for its "roundness", could be an out of spec wheel and tire.

Also, a steering stabilizer is inexpensive (around 50-75 bucks) these days, you can buy a kit for it and it helps the "wobble" issue you are having on your Jeep, it is basically a "shock absorber" for your steering wheel and easy straightforward install.

Lastly, check your front and rear suspension and frame mounts, etc.

Good luck.

:}

Link Posted: 10/12/2007 7:14:50 AM EST
My first thought was a tie rod. I had this happen to me in my Xterra. Was going down the road at about 40mph and all hell broke loose. I thought I was going to wreck before I got it slowed down. It was jumping all over the place. The threads on the shaft had begun to flatten out inside the tie rod end causing the shaft to pull in and out of the tie rod end, thus causing the wheel to go crazy.
Link Posted: 10/12/2007 7:14:59 AM EST

Originally Posted By rob78:

Originally Posted By Vaquero45:
Like a few of us said in the other thread...

The cheapest place to start is checking your tires. Make sure they are balanced well and wearing evenly. Rotate them see what happens.

snip


check your tires. There's absolutely no reason to start spulling suspension parts.

Rotate and balance them. If you haven't done this, I'd damn near guarantee that's your problem.



The tires have about 50% left on them, and I haven't balanced or rotated them since I bought the Jeep a year ago. I was going to replace them anyway, so this sounds like one of those "it won't hurt to try" kind of things, since I need new tires as it is.

The thing is, I've driven plenty of vehicles with out of balance tires, and the vehicle vibrates consistently and predictably at certain speeds. My Jeep is different. It'll cruise along just fine at 65 mph (no vibration) then....BAM! Violent shaking 10 seconds later.
Link Posted: 10/12/2007 7:18:36 AM EST
[Last Edit: 10/12/2007 7:22:42 AM EST by Boomer]
My bone stock CJ with 180,000 miles had a bit of Death Wobble at highway speeds. I replaced worn ball joints, axle u-joints, and tie rod ends. Upgraded the steering gear box, mount, and steering shaft. Had the tires balanced and tried rotating them from front to rear. All of this somewhat reduced but never completely eliminated the DW. I figured the root problem was somewhere in the fatigued front leaf springs or worn spring bushings or shocks. Now that I added an all new lifted suspension system, shocks, and new tires the DW has completely disappeared. I would suggest taking a close look at the condition of your leaf spring bushings and shock absorbers.
Link Posted: 10/12/2007 7:19:11 AM EST
DzlBenz is correct. You have a resonant frequency issue in your suspension. Once the suspension starts to resonate, it reinforces itself (Think Tacoma Narrows Bridge).

Check all your spring shackles. If those are okay, replace your shocks.
Link Posted: 10/12/2007 7:36:13 AM EST

Originally Posted By JFP:
My Grand Am would do the exact same thing and it turned out to be the front brakle rotors.

55-60 is weird cause that seem to be the most difficult speed to balance a tire at. Try a different brand tire and replace your ball joints and end links.



On my old tires, that is the speed it'd begin to show. As someone else mentioned, a tap on the brakes usually quieted things down.

I figured I'd deal with it. Until I was making a long sweeping turn on an entry ramp at 55 and hit a bump where the road meets the overpass. Thought I was gonna buy the farm on that one. Damn near had to pull over to collect myself.

new tires and the problem went away. Until they wore sufficiently and I had to get them balanced.
Link Posted: 10/12/2007 7:36:28 AM EST
subnet, I would bet the farm it's your balljoints. with a sua leaf sprung vehicle most anything else in the suspension wont cause DW. jack up one side of the front end and put a hand on top and bottom of the outside of the wheel and see if it will wiggle. bet yours will go about 2 inches or more which is dead nuts worn out.

Link Posted: 10/12/2007 7:36:42 AM EST
Link Posted: 10/12/2007 7:39:14 AM EST
I would check the caster on the front end. It might be a case of "shopping cart shake"

Link Posted: 10/12/2007 7:40:00 AM EST
[Last Edit: 10/12/2007 7:42:58 AM EST by Merlin]
My bet is it's the tires, especially since you report that you haven't done anything with them in the year or so.

Cheap and easy experiement: Add 3-6 oz. of anti-freeze to each of your front tires. Deflate each tire, let it sit on the ground. Take off the Schrader valve guts, slide on a rubber tube sized to fit, put the other end in a small container of antifreeze. Add 3-6 oz. to each tire. Reinstall Schrader valve guts and reinflate tires. Drive and report.

The antifreeze will act as dynamic tire balancers, solving the problem if out of balance tires are causing the problem. It's not likely out of balance tires are the entire cause of the problem but they could be a contributor; this eliminates them as a factor.

If it still does it with the antifreeze in the tires, one or more tires are probably out of round or the wheel itself (or both) are out round.

Good luck.

Merlin


Link Posted: 10/12/2007 8:02:03 AM EST

Originally Posted By PAEBR332:
You should do a live webcast from your driveway. Arfcom could guide you on your misdiagnosis, argue endlessly about what they are seeing in your suspension, etc...


Someone else would have to be driving for that vehicle to go over 35MPH...

Link Posted: 10/12/2007 8:02:17 AM EST
i have a old cherokee that had the same issue. long story short steering stabilier looked good, replaced it and problem gone.
Link Posted: 10/12/2007 8:02:48 AM EST
Everytime I had death wobble, it was a combinatin of out-of-balance tires (Super Swampers ;) ) and a loose trackbar or bad trackbar bushing. However, that is on a coil-sprung Jeep. Haven't really heard of it too much on leaf-sprung Jeeps.


First thing would be to balance/rotate tires. When I switched to my road tires, I never got DW. When I put my off-road tires on, I would always get it.

Check all your front suspension bushings. I know most people take off the front trackbar on YJ's because it's really not needed. You may want to put it back on if it's been removed. It's the part I've expertly circled in yellow.

Also, try switching to a Old Man Emu steering stabilzer. They run about $50 and while they only help to mask the DW problem, every little bit helps.
Top Top