Death wobble despite trying (almost) all solutions

[oldmantompkins]

Can a bad ball joint cause death wobble?

 

[yardape]

Well, you might try changing things to change the "harmonics"--try adjusting your tire pressure up/down, might make enough of a difference.

FWIW: Two pounds and new tires made a huge difference on my ZJ. I went from BFG AT's to Toyo AT's which have a stiffer sidewall. Then playing with the pressure going from 32 PSI to 30 PSI made another huge leap. Now I never get DW where as it use to plague me. At 50 mph I can still faintly feel it start to wobble on occasion but it never gets out of hand.

 

[Ole703]

Hi, Its my first post on . I typically hover around on MN-Jeep.com.
I am new to the forum but not new to Jeeps. Aren't you all assuming worst case scenario? I read the thread. Not one person suggested that he have is front two tires put on a wheel balancer. You may have lost a wheel weight especially if they are the ones that stick on.

If one tire is out of balance it will cause your dana 30 death wobble.

 

[joe_peters]

Hi, Its my first post on . I typically hover around on MN-Jeep.com.
I am new to the forum but not new to Jeeps. Aren't you all assuming worst case scenario? I read the thread. Not one person suggested that he have is front two tires put on a wheel balancer. You may have lost a wheel weight especially if they are the ones that stick on.

If one tire is out of balance it will cause your dana 30 death wobble.

As his DW only presents after hitting a hole or rough spot on the road, it is not very likely a wheel balance issue. Doesn't mean it couldn't be, just unlikely.

 

[br1anstorm]

Joe - you're right. I really don't think it's a wheel balance issue. I know what that feels like - on my Jeep and other vehicles.

This DW only happens when triggered by a particular combination of pothole (or bump) and speed, and usually of course it's only one wheel that hits the irregular surface. This seems to destabilise the front end and provoke a pretty violent shaking.

I may try playing with tyre pressures (that costs nothing!). Part of the problem is that it's hard to "test" whether or not it has been solved, as the DW only occurs in a specific - and unpredictable - set of circumstances.

I know the old shocks were tired, so I didn't mind changing them, and I assumed the bushes were worn. But as I said before, I can't just keep swapping out other parts in the hope that one change or another will magically solve the problem!

 

[90XJay]

Take this from a guy who replaced his entire front end before finding his death wobble. Just take the 20 mins to swap your front tires to the back and see if it changes anything. It doesn't cost you anything but a little time to check. I bought:
New control atms
New trac bar and mount
New ball joints
New wheel bearrings
New tie rod ends all around
New steering box
and it was the stupid tires. Not saying it will fix your problem but if I had just listen to that suggestion I wouldn't have spent all that money. You say parts are expensive there so just TRY it. My .02. I guess the belts in my tire were all messed up. It would only wobble if I were going over 45 and only if I hit a small bump in the road.

 

[Ole703]

My death wobble would only hit at certain speeds. Sometimes it would only occur after a bump in the road. It was my tires being out of balance. It doesn't hurt to check.

 

[br1anstorm]

Thanks both 90XJay and Ole703.

Just as soon as the temp get above zero and the snow melts a bit, I'll start messing with changing-round the tyres and adjusting the pressures.

Of course it's worth trying - I'm desperate and angry enough to look at any solution. But I'm still not sure that's the source of the problem. How could slightly unbalanced tyres cause DW shaking so severe - when it happens - that it almost loosens the fillings in my teeth at 45 mph, and won't stop until I brake or slow down? Yet the Jeep runs straight and true without the slightest twitch or steering-wheel shimmy at any speed on a smooth road.

Oh by the way - in case it is of interest - I have Michelin Synchro tyres at the moment. They are essentially highway road tyres, and they don't have aggressive treads for mud, snow and off-roading. Michelin are supposed to be among the best for quality and durability. I previously had Toyos, and before that Goodyears, and had no problems with either (though the Jeep itself was younger then!).

 

[heyhar]

An unbalanced tire, however slightly so, will behave better at a lower speed, and a constant coefficient of friction. Upset that balance, and it's like unleashing all the stored energy that's been building. It becomes unstable, and a good, one wheel bump or pothole, or better yet, a diagonal seam in the road is all it needs to explode, manifesting itself in the rythmis gyrations that most of us know all too well. You've also mentioned Goodyears. These tend to be rather soft in the sidewalls, absorbing their fair share of road surface imperfections. That's why they came standard on most Jeep vehicles. Whenever I've burned through the OEM tires on our Jeeps, and replaced them with another brand of SUV-sized tire, the new ones are noticably harsher. I have a set of Firestone Indy 500 tires now, and they are as smooth as OEM tires.
You made mention of zero degrees...if you guys used Farenheit, it would always be warmer! Doesn't 32* sound better than 0*?!!!

 

[yardape]

Another vote for steering damper. While I agree with everything that has been said thusfar about steering dampers just masking a problem, I just put a new damper on mine and what a difference. Sometimes DW can be caused by a set of circumstances that will never be discovered. If you've had DW for a long time like I did, (at least 60k) you've put the damper through hell and back. Mine was shot. Between Kevins' trackbar, new tires, keeping the tires at 31 psi and a new steering damper my DW is gone.

While I have not discovered the root of the problem, no one would ever know from driving my Jeep the history of its woes. I'm not the original owner as is the case with many Jeeps on this site. Maybe it has a well masked fender bender or engagement with a rock that tweaked the body just enough that it will never be right. While perfection is an admirable goal, knowing when to quit and say "good enough" is just being realistic. Just offering it up as food for thought.

 

[jcnoble]

Did you check the toe in? I adjusted mine myself, theres a post on it.
I had bad death wobble and did everything, It went away after bigger tires and toe adjustment, oh and check the caster angle, not sure which one fixed it.
Just my 2 cents.

 

[Ole703]

Yeah I couldn't believe it was only tire balance on my Jeep till I put it on a balancer. My jeep would literally hop down the road. HeyHar did a good job of answering your question for me.

I am not saying for sure it is a Tire balance issue. But, I always start with the simplest and cheapest fix first.

 

[PaulJ]

I had a similar problem and it was caused by the tires. A regular spin balance didn't help but when I had them road-force balanced, the problem went away. A balance machine that does the road force balance has a roller that applies a load to the tire. I don't know if you can find a similar machine in the UK, but here's a link http://www.gsp9700.com/pub/features/how.cfm

 

[PaulJ]

Here's a link to find Hunter equipped shops in the UK http://www.alignmycar.co.uk/

 

[br1anstorm]

OK, time for an update. DW problem still not solved.

In recent weeks I have

- done a thorough visual check underneath with steering turning full lock both ways to see if there is any slackness or movement at any links or joints. No obvious problem;
- tried running both lower and higher tyre pressures. Makes no noticeable difference;
- swapped the two front tyres (left and right) over. Still get DW;
- had all the alignments (camber, caster, toe-in etc) checked. All were pretty much exactly to spec.

So the next items on the checklist - and suggested in posts above - are the steering damper, and/or the track bar (which over here I think we call a Panhard rod).

Some say changing the damper may be a quick fix but just masks the symptoms without resolving the cause of DW. But I'm getting to the point at which I feel like trying it anyway.

As for the track bar, I have what might seem an idiot question for heyhar and others who suggested it. The track bar is just a piece of metal rod with a slight curve in the middle to get it around the diff. Other than getting bent off-road, how and why would it need replacing? Unless it is prone to metal fatigue, surely the only way it could become a problem would be if the bushes or mountings at either end were worn/bent/misaligned? On my stock XJ, the bush at the axle end is new, and the mounting bracket at the chassis end seems absolutely fine and solid. Am I missing something? I just can't see a reason to replace the track bar, nor how it would make any difference!

 

[heyhar]

OK, time for an update. DW problem still not solved.

Some say changing the damper may be a quick fix but just masks the symptoms without resolving the cause of DW. But I'm getting to the point at which I feel like trying it anyway.

I like a good, 'resiliant' damper, as, just like a good shock absorber, it slows any harsh movement or vibration wanting it to move. They will develop a dead spot in them over time, typically right in the middle where they spend most of their life. It's trule that it may be just a band-aid for DW, not a cure, but maybe a brighter mind than ours saw a need to 'damp' gyrations of a certain frequency, before they lead to others. Maybe the only way to truly cure DW, and other maladies which afflict the XJ, is to park it! Just kidding!

As for the track bar, I have what might seem an idiot question for heyhar and others who suggested it. The track bar is just a piece of metal rod with a slight curve in the middle to get it around the diff. Other than getting bent off-road, how and why would it need replacing? Unless it is prone to metal fatigue, surely the only way it could become a problem would be if the bushes or mountings at either end were worn/bent/misaligned? On my stock XJ, the bush at the axle end is new, and the mounting bracket at the chassis end seems absolutely fine and solid. Am I missing something? I just can't see a reason to replace the track bar, nor how it would make any difference!

You're right, the trackbar/Panhard rod is an inanimate length or steel. But, the magic is at the ends, in the bushings. I'll assume that yours is RHD, so your balljoint, chassis end is on the right. The balljoint goes bad, some much quicker than others. My '96 has 158k miles on the original, my friend has a '95 ZJ with over 200k, still original. My '92 lost its first at 100k, and has had four more in 100k. No rhyme or reason. Besides, Panhard is of French origin, so let's call it a track bar!

On my stock XJ, the bush at the axle end is new, and the mounting bracket at the chassis end seems absolutely fine and solid.

Typically, the balljoint is toast long before the rubber bushing.

Please, with all the other stuff you've done, change the track bar and the damper. You owe it to yourself! Then report back.

 

[90XJay]

- swapped the two front tyres (left and right) over. Still get DW;

Front to back, swapping them left and right could still mean the front end is seeing lot's of unbalance. Other then my tires the other issue that usually caused my DW was my tracbar but it was minor compared to my tire problem. And the reason I tell you is this was the worst death wobble I had ever seen lol. Ask Billyjp2, xbobj, and xjbaadleej how bad my wobble was lol scared the crap out of them and they weren't in my jeep.

 

[BrokenSockets]

Like 90XJ says, front to back is the best way to rule out a front wheel balance problem AND is also the correct tire rotation procedure as per the manual and FSM.

I had a similar issue on my 92 and it was the track bar. Even though it LOOKED ok and did not display any gross sign of wear, the joint at the frame mount was the problem. You should also check the hole in the mount to make sure it has not been ovalled. That can do it too.

On the damper, I'm sure it has a purpose but replacing it was never the magic pill for my MJ/XJs.

 

[blondejoncherokee]

a bad steering stabilizer wont cause DW, its merely a band aid if your steering is good you dont need it.
but it doesnt hurt to replace it if it is bad.

how new is the trackbar?
i second checking the trackbar bushing and TRE.
have someone crank the wheel back and forth and watch the trackbar
is the trackbar bushign at the axle end good?
is the trackbar TRE at the frame good?
then crank on the 4 mounting bolts for the trackbar bracket. make sure that thing is tight as hell. if its even a little loose it can casue DW. i know it from experience, it happened to me one day. cranked it down, then it was gone.
are there any frame cracks around the trackbar bracket?
check ball joints for play. shake tires around (off the ground first)

check control arm bushings. check all upper and lower control arm bolts for tightness.


when was the last time tires were balanced?
ive seen bald unbalnaced tires casuse DW , on my jeep actually...

id put money on a bad trackbar and/or a loose mount.

i drove back from the rubicon in september from tahoe to sac with 2 loose axle side control arm bolts ready to fall off, same for the lowers, and a slightly loose frame side trackbar bolt with no DW.

so it makes me think your trackbar bushing and/or TRE are totally shot.
replace it , crank on the mount (18mm bolts) and go from there

someone said no one suggested balancing on page 2, when it was one of the first things posed on here...by me...

 

[yardape]

Go to Kevin's Offroad and even if you don't buy anything its pretty informative about death wobble and his kit did resolved mine. Like you I spent years being a purist trying to "fix" it. Unfortunately Jeeps are like people: some you can reason with and resolve matters while others you have to throw a blanket over and beat the crap out of. Without the steering rack, the wheels would flop around. Steering components are suppose to, among ather things, solidify the steering system. Sometimes it just doesn't. No one was suggesting I think replacing your stock trackbar with another. Kevin's bar is heavy duty and less prone to flexing. Furthermore, the bracket he sells with it is stouter than the original and drops the bar down farther providing better side to side resistance. The bar alone didn't fix the deathwobble but when I added the steering stabilizer the wobble was gone. It made me realize that after years of DW my stabilizer was probably toast. Yours may be too from the extra stress put on it. Until I got the kit I used to call it a patch too but the reality is that the kit provides resistance that prevents the wobble from starting in the first place. I still occasionally feel a tiny little pulse but its very minor and the kit keeps it from getting out of hand.

I should also say that this was on a ZJ not an XJ but its the same setup. Please know that I'm not affiliated with KOR or KOR products and there are plenty of offroad suppliers that I despise so I don't say all these things easily. I'm just saying that the kit seems to have put the wobble between a rock and a hard place so its got no where to go.