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Death wobble Help


mastertech
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I know that this is going to be a to new of car for some of you , but we are at witts end. And since chrysler tech advisors cant figuer this out though i would ask people with more experiance and common sense. I work at a chrysler dealer ship and we are working on a 2007 jeep wrangler with a wobble so bad it will rip the steering wheel out of your hands and will also cross the center line this thing is bad, we have changed the steering stablizer shock steering box ball joints tie rod ends have had the alignment check within specs.shocks basicly the complete front end rebuilt still the same even played with tires (diffrent ones along with wheels) tire pressures. If any one has any idea even if it is way out there i would like to know it. Even if the radio is on the wrong station right now customer has it on country I would like to know. Either let me know on here or even call me at 814 371 8152 and ask for mel Any help of any kind will be welcome as this jeep is almost in a buy back situation at thei time.

thank you very much I know someone out there will have an answer to this problem

thanks

Melvin Schwentner

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Ok, you asked so I'll tell you about our experiences - put some new brake rotors on there and torque them down correctly! Ours had problems and even new rotors that are torqued incorrectly will be an issue. Anytime we have tires changed or get a wheel pulled for an annual vehicle inspection we retorque them correctly ourselves and have not had a problem since. It has also been the solution for several friends with Jeeps too. I think there is actually a service bulletin on the problem. Let us know what you find out.

Terry

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will check the rotors, I did forgot to mention tha this happens with out using the brakes usually at 40 50 mph on a turn. I nornally check toque on the rotors but i havent check the mounting flange tho. hmmmmm need to check that thanks

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Melvin,

I'm not technician, but has anyone followed this vehicle down the highway and looked at both sides while it's moving? At least if a wheel or hub is bent, you'll possibly narrow your search down.

I saw a big truck go through my town yesterday and heard the trailer squeeking, then noticed a wobbling wheel set, with no way to contact the driver. frown.gif

Wayne

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We had 1997 Ford Taurus station wagon that behaved like that. The dealership couldn't figure it out. A local guy with his own repair shop knew right away what it was. Our Taurus wagon was one of the ones that had a special power steering assist module on it that kicked in when the car was turning. When it got low on the power steering fluid it would jerk like driving over rocks.

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well we replaced the rotors and checked the hubs for trueness then matchedmounted the rotors right side was 0.005 left side was 0.008 road test still wobles bad. If you warch the wheels you can see them both start to move back and forth very fast and can hear them chirp on the pavement. Has plain power steering we have even swaped out a new box from one on the new car line with same results. But that is not saying that may be,could there be air or possiably a hose problem? Hmmmm need to check that in the am. it has to be something simple just stating us in the face and we cant see it. keep the ideas comming i will check anything that anyone says even if already been done we have to get this fixed thanks will let you know what fixes it.

anything

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no pitman arm or idler arm on this set up has one tie rod end on the steering box which goes to the right side knuckle then another rod with 2 tie rod end on each side running between the right and left wheel all parts new along with ball joints but could one be to tight and binding?

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One symtom of a tight balljoint or kingpin, is that the car will wander badly. It would be a handful to drive.

I'd run a carfax on it to see if it was wrecked.

Does it have aftermarket bigger offset wheels?

Go back on the alignment rack. "Within specs" means what ? smile.gif Make sure the caster is THE SAME on both sides....specs may allow a difference, but get them the same. Also see if you can find a spec on "toe out at turns" and check that for sure.

Some antique hotrods had some improvement with going to a slight toe out. Some had help from major caster change.

Death wobble usually comes in at very slow speeds, and more so on straight road and then hitting a bump with one or both front wheels. Speeding up usually will stop the gyrations, so I am puzzeled why yours is "on a corner" and a much higher speed.

Have you also swapped all 4 wheels with a donor car?

Death wobble normally is each wheel trying to steer more than the other...then one wheel pulls the tierod which steers the other wheel. They end up fighting eachother.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Robin Coleman</div><div class="ubbcode-body">This is gonna sound very stupid. but if this is a 4X4, make sure the hubs are both locking and unlocking together.</div></div> I am a firm believer in that no question or answer here is stupid. We all learn certain things certain ways. Sometimes simple trial and error works. My '31 coupe has the "slow death wobble" as someone called it. I will be going along straight, about 30 mph, hit some railroad tracks or a bump and they're off. Man, oh man it feels like the front end is going to fall off. I am trying to figure out if it's the king pins or tie rod ends or???

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: keiser31</div><div class="ubbcode-body"> My '31 coupe has the "slow death wobble" as someone called it. I will be going along straight, about 30 mph, hit some railroad tracks or a bump and they're off. Man, oh man it feels like the front end is going to fall off. I am trying to figure out if it's the king pins or tie rod ends or??? </div></div>

I'd disconnect the drag link by taking off one of the straight slotted plugs on either end of the drag link...then jack it up to feel if your king pins are stiff...or worn out.

If that's fine, then I'd buy a pair of "caster shims". These are still made today, but likely will be too wide for those skinny leaf springs.

Then just trim them to fit.

The tapered, wedge shaped shims go between the axle and springs. You want to tilt the axle back...meaning the top of the king pin is leaning back. Also set the toe around 1/8".

I had a 50s built 29 DeSoto roadster hotrod in 1970. When I got a test ride from the seller, he ran it hard on some rough city roads and it was fine. I got it home and put Keystone mags with more offset and it went into violent death wobble. Even with the old wheels put back on, it still did it and one day it shook so hard the windshield frame fell out, the right door flew open and jumped off the hinge, plus the open sided hood fell off. I parked it permanantly and a friend told me about "hershey", and I put the car back to stock.

Oh, I ended up buying so many parts cars and pieces, that I ended up building a 30 DeSoto roaster hotrod in 70-80. I kept it till 85. It's still out there but a lot was changed since 85. Google image search for " 1930 DeSoto CONVERTIBLE" (instead of ROADSTER), and you will find it quickly...the red one. smile.gif

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You did say you wanted to hear about anything that might cause it, in the 1960's Lockheed Electras were breaking up in flight due to this.

Whirl mode was nothing new. It was not a mysterious phenomenon. As a matter of fact, it is a form of vibrating motion inherent in any piece of rotating machinery such as oil drills, table fans, and automobile drive shafts.

The theory was devastatingly simple. A propeller has gyroscopic tendencies. In other words, it will stay in a smooth plane of rotation unless it is displaced by some strong external force, just as a spinning top can be made to wobble if a finger is placed firmly against it. The moment such a force is applied to a propeller, it reacts in the opposite direction.

Now suppose the force drives the propeller upward. The stiffness that is part of its structure promptly resists the force and pitches the prop forward. Each succeeding upward force is met by a protesting downward motion. The battle of vibration progresses. The propeller continues to rotate in one direction, but the rapidly developing whirl mode is vibrating in the opposite direction. The result, if the mode is not checked, is a wildly wobbling gyroscope that eventually begins to transmit its violent motion to a natural outlet. The vehicle.

Not much help, but it seems you have covered everything.

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You do get tire chirp on an older 4x4 with cross style u-joints on dry pavement when locked in 4wd, but constant velocity joints eliminate that. I don't know what this car uses, but being that this is at a Chrysler dealership, I'd think they have made sure it's not in 4wd.

Tire chirp also comes from violent death wobble as the tires rapidly steer from one side to the other.

More thinking on why it is doing it on turns:

As you know, a steering gearbox has zero freeplay at dead straight, but lots of engineered slop at turns to allow for proper feel in the turns.

I would think that this car has a problem with either the toe-out-at-turns, or an incorrect caster at turns. Then because there is a lot of play in the box at turns, then the offending wheel has "room" to turn where it wants to.??

I'd still be more confident to find out if they have swapped the entire set of tires/wheels with a donor car. i have seen a defective chord in a tire do strange things, at precise speeds, to the handling. However, a bad chord usually shows up at a dead crawl on a smooth parking lot, when you feel the car twitch to one side on each revolution.

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not to change the subject but my grandson was born early this morning!!!! Xavier came into this world at 9lbs 9oz. Trying to get ahold of his dad right now he is in Iraq somewhere. now back to jeep that is the strange thing We sold the jeep new but this problem never stated untill it hit 30k. We swaped tires off of a nother wrangler off the lot (new 2 miles) Im thinking caster is off dont know if can adjust solid axle looks as if can be but no cam bolts

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Hey Mel,

Congrats on the new bundle of joy.

I have been watching this topic with great interest. I'm not sure this feature was across the board but I know that on some Wranglers they had an actuator that engaged or disengaged the stabalizer bar. This feature was created to allow for more extreme off roading and to extend the front suspension travel.

Does this vehicle have that feature and if so have you guys checked that yet.

You said that you have been working with the call center. do you have a case opened and a case number on this?

Keep us updated

Rich

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Dear Melvin:

About 1964, we had a brand new heavy truck at the IH plant in Fort Wayne that did the same thing at about 40 MPH. It was brand new and everything checked out as new. It had us all perplexed. It had no shock absorbers as that setup didn't require them. My solution was to put a shock absorber on ONE side only. This destroys the feedback thru the system, as one side shakes at different frequency from the other. Put a very stiff shock on the passenger's side and a weak one or none at all on the driver's side and see what you get.

Normally, there's enough mass and weight variance of parts that things cancel themselves out. This is one of those things that the closer you get to "equal", the worse it gets.

Regards, Dave Corbin

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Hi Mel,

I did some sniffing around an this is what I came up with.

1. The vehicle is equipped with standard "U" joints not CV joints. The lock up is in the front diff so they are spinning at all times the vehicle is moving. If one side or the other u-joint is binding it could cause some serious shaking.

2. The bushings in the lower control arms are notorious for becoming soft over time. Problem is they are not serviced seperate from the arm. If you have access to another vehicle and can swap out the lower control arms do so and give it a drive.

3. On a couple more extreme cases the shake has been corrected by replacing the factory steering stabalizer with a heavier aftermarket unit like a Skijacker. We were never able to determine the combination of circumstances that created the condition but the heavier shock fixed it.

Good luck and let us know how you make out.

Rich

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Put the Jeep on a lift. Just off the ground enough to clear the tires.

Stay in the car with foot hovering over brake pedal and the service brake applied, HARD.

Start the car and give it a little gas.

Do this out side if possible but not on jack stands.

Thats were I would start.

Are you sure its the front end?? If it is, check the little balancing weights on ALL the drive shafts. They are usually spot welded to the shafts to compensate the rotating mass.

Chances are that one of the drive shafts should have been rejected at the factory and some worker put the maximum weight on to balance the shaft and it was still out of balance, slightly. This large amount of weight got thrown off, (broken spot weld) and now you have an extreemly un balanced drive shaft either to the front differential or to the wheels on the front.

Personally I had a bad experiance with a 2002 Jeep Cherokee and I'll stop there and be nice. The ole 258 6 cylinder is a great bullet proof motor but I would rather not get into the rest of the vehicle.

Bill Harmatuk

An old saw mill and pulp mill mechanic.

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Mel., something is worn or binding. It drove good for 30,000 miles and now 4 lanes aint wide enough? If I understand it it is a one owner vech. and never wrecked. No one has messed with the front end and everything looks good. I would look real close at bushings (rubber) and anything that can change the hight of the drag link/center link. Next raise the jeep on the hoist and crank the wheels hard one way and then the outher. Rotate the wheel by hand and look at the u/joints (axle to wheel) as if you are moving the jeep. I mean spin the tire by hand.Is the joint rotateing free?? Is there any rust dust at the u/joint caps?? A hundred years ago my shop and Parts Plus sent me to Missouri to the Moog training center for a week of intensive training on front end repair. They have a group of instructors that can and will assist you with problems like this and a tole free number. If you have tryed all suggestions with no cure call them. If they can not help then buy it and burn it.BTW are you a member of and have you tryed IDENTAFIX.??

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sorry didnt get back sooner on the update. Was helping out with the local firemans parade this weekend. Any way the new stablizer shock didnt arrive on friday like the parts store promised(we have a hard time getting parts that are out of the ordanary) But i did have a gentelman call me and suggested that we remove the drive shaft and both axle shafts install stub shafts and drive to see if wobble went away, dont have any stub shafts around either unless we take apart the axle shafts, which we will do on monday. Only problem is that the service manager gave the customer back the jeep for the weekend , I told him not to because if something would happen if they loose control of the jeep because of the wobble that we could be at fault because we know there is a serious handling problem. Hopefully the bring it back on monday. All parts should be here then.

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sorry it has taken so long to reply I should have answered sooner, but we have just gotten the jeep back in on friday been having trouble getting parts from chrysler everything has been on back order. did tryed a new stablizer shock on fri. but did not help that is only a bandaid. Can not get bushings by them self have to get entier control arm did find one that the bushing was soft changing all 4 arms should be done sometime monday afternoon also going to try to get the front end alined on mon going to go to our other store and do it my self so i know that it is done right and not a set the toe and go type.Agin sorry for not keeping you all updated there is no excuse of not

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And its fixed!!!!!!!!!!! the bushings fixed it. I changed all the control arms ,the only way could get them Put about 20 miles on today with no problems, going to drive it tomorrow alot more and on diffrent road surfaces just to make sure. Agin sorry about the time it took to reply things just kinda went fast along with having as hard time to get parts. I just want to thank everyone that helped we tryed every idea that was put to us. Agin sorry about the time there was no excuse I should have taken the time to keep everyone informed as to what was going on. I have a lot of problem cars that i work on during the week appx 4-5 after everyone else works on them i end up takeing care of them not only from our stores (4) but from other places in the area. So at times things kinda get away from me ----Still no excuse!!!! Agian thanks to everyone who helped..

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