18 replies to this topic

[TJ Jake]

I really hate to start a thread about this but I'm at wits end. My 05 LJ will not stop shimmying over bumps no matter what I do. If I drop the tire pressure below 30 PSI, then I will get full blown death wobble where it wont stop unless I slow down to 25 mph. I've replaced the Track Bar (mopar), Ball Joints (spicer), and Upper & lower control arms (mopar). There is absolutely no play in the steering box, tie rod ends or the wheel bearings, and I've double checked that every nut and bold on the suspension is torqued to spec. The Jeep is stock with the exception of 31" BFG A/Ts.

I'm hoping to get some insight on anything I might be missing, because I've looked over everything with a fine tooth comb. I've even had the front end techs at work look at it with me and they're just as stumped. I'm going to align it at work tomorrow, but I've always been under the impression that the toe should only change if somethings bent or I modified the suspension. Any advice would much be appreciated

[ImperialCrown]

Steering Damper?

[Bob_Sheaves]

http://www.allpar.co...__fromsearch__1

[DaveAdmin]

I'm going to guess it's a wheel or tire. Did you try rotating wheels and seeing if that had an effect?

Quote

Death wobble is a kids terminology, we called it "Shimmy" back in the day. It has nothing to do with solid axles, it does have to do with any suspension that has a continuous tie rod (which nearly all solid axles have) to connect the front tires.
Shimmy is normally cause by aftermarket application of larger tires, lifts that change the front axle setting for toe, or caster and camber, or a combination of worn or damaged parts.
An out of balance tire, a broken tire cord, a bent wheel, or worn shocks can be the cause.
Worn or damaged tie-rod ends, steering box, steering arm ends or a worn steering stabilizer can all be causes. As can improper alignment. Most shimmy's present themselves at certain speeds and go away at higher or lower speeds, some are severe enough to require coming to a complete stop. They can be scary to the first timer who is not expecting such violent behavior after hitting a pot hole, railroad track or a simply accelerating past the point of the damaged components triggering speed.
Most shimmy is associated with improper toe-in or toe-out, in combination with oversized tires, but any of the conditions listed above can cause it.
It is similar to but not associated with, a vibration at certain speeds caused by a lift that creates a too severe driveline angle and imbalance in the propeller shaft (driveline).
They are easy get, in a modified Jeep, harder to find for the inexperienced. They have nothing to do with design, until those design parameters are tampered with, or damaged.
It's been around since the 50's or earlier and is not limited to Jeeps.
Bob can fill in us in on the technical aspects and/or items that I may have left out.

[MoparNorm]

TJ Jake, on January 26, 2012 at 11:34 pm, said:

I really hate to start a thread about this but I'm at wits end. My 05 LJ will not stop shimmying over bumps no matter what I do. If I drop the tire pressure below 30 PSI, then I will get full blown death wobble where it wont stop unless I slow down to 25 mph. I've replaced the Track Bar (mopar), Ball Joints (spicer), and Upper & lower control arms (mopar). There is absolutely no play in the steering box, tie rod ends or the wheel bearings, and I've double checked that every nut and bold on the suspension is torqued to spec. The Jeep is stock with the exception of 31" BFG A/Ts.

I'm hoping to get some insight on anything I might be missing, because I've looked over everything with a fine tooth comb. I've even had the front end techs at work look at it with me and they're just as stumped. I'm going to align it at work tomorrow, but I've always been under the impression that the toe should only change if somethings bent or I modified the suspension. Any advice would much be appreciated

Go to the link Bob gave and read every post, by Bob  and myself. It can be alignment or worn components, but wholesale replacement of parts is not the answer, nor is a replacement of the stabilizer, which is just a masking device.
Fix the issue, then replace the stabilizer last. First step, alignment on a computerized alignment machine/rack with all 4 wheel capability, such as found at 4 Wheel Parts. Then dynamic spin balancing of all four tires, do not use one of the "major" tire chains, use a shop that has the state of the art equipment AND specializes in off road tires.  Get the Jeep back to factory alignment specs and you'll be fine.

[TJ Jake]

Thanks Everyone for the replies, much appreciated!

Bob_Sheaves, on January 27, 2012 at 08:05 am, said:

http://www.allpar.co...__fromsearch__1

Lots of good info in that thread, thank you.

DaveAdmin, on January 27, 2012 at 09:42 am, said:

I'm going to guess it's a wheel or tire. Did you try rotating wheels and seeing if that had an effect?

I swapped tires with my 2000 TJ that has Goodyear MT/Rs on it. On the 2000 TJ, they're smooth and I have no shimmy. On the 05, it's bad. Even worse then the BFG's.

MoparNorm, on January 27, 2012 at 10:13 am, said:

Go to the link Bob gave and read every post, by Bob  and myself. It can be alignment or worn components, but wholesale replacement of parts is not the answer, nor is a replacement of the stabilizer, which is just a masking device.
Fix the issue, then replace the stabilizer last. First step, alignment on a computerized alignment machine/rack with all 4 wheel capability, such as found at 4 Wheel Parts. Then dynamic spin balancing of all four tires, do not use one of the "major" tire chains, use a shop that has the state of the art equipment AND specializes in off road tires.  Get the Jeep back to factory alignment specs and you'll be fine.

I mounted and balanced the tires myself using the Roadforce balancers at work. And while I did have it balanced to 0oz on both machines, I still feel an imbalance in one of the tires. Not sure what that's about...

I did do an alignment when I put the tires on to. Caster and camber were dead on, but toe was off. I set the toe to factory specs, and didn't have an issue for maybe 5,000 miles. Since then is when I replaced the bushings/ball joints and track bar. I do have a Rancho steering stabilizer on there, but not because of the wobble. 2 Years ago the OEM one was leaking, so I replaced it.

Unfortunately I was too busy today to throw the Jeep onto the alignment rack, so it'll have to wait til next week. I'll just have to drive the CJ7 around until I get to it.

[DaveAdmin]

Slipping thingie inside the tire? (I'm tired and hoping you know what I mean.)  Had that problem once. Didnt' show up on the regular balance.

[TJ Jake]

Well, I aligned it exactly to spec today...no change. Grrr.

DaveAdmin, on January 31, 2012 at 01:39 pm, said:

Slipping thingie inside the tire? (I'm tired and hoping you know what I mean.)  Had that problem once. Didnt' show up on the regular balance.

Tyrons? I think thats what your talking about, but I don't have those.

[DaveAdmin]

No, tire belts.

[Bob_Sheaves]

Delaminated belts?

[DaveAdmin]

Shifting belts within the tires. I had a defective radial that did that, was told it's not uncommon. Solution was a replacement tire.

[MoparNorm]

DaveAdmin, on February 2, 2012 at 09:15 am, said:

Shifting belts within the tires. I had a defective radial that did that, was told it's not uncommon. Solution was a replacement tire.

That can cause a vibration and an inability to hold your line when driving straight ahead, but the condition know as Death Wobble is much more severe and extreme than that.
DW has been known to break welds and rip brackets and stabilizers from the vehicle, it's violent enough to break fingers that are in the way of the oscillating steering wheel.

That being said, a bad tire on a vehicle with other issues, can be the fuse that lights the DW condition.

[68RT]

Having the center of the tire tread and the knuckle pivot point meeting the road at near the same point will absolutely destabilize the steering stability. Change the tire diameter, offset, camber or worn  knuckle bearings all affect that issue. If it is at that point, the tire does not know if it should tend to toe in or out and any road irregularities will set off a wobble.

[TJ Jake]

Well, I'm happy to say I finally figured it out!

It was the lower control arms. The races that the bushings press into became worn out and just caused the bushing to sit in the arm very loosly. I took the arms off and the bushings just fell out out of them! I put new arms on and the shimmy is gone. Now I need to have a celebratory wheeling trip.

[MoparNorm]

TJ Jake, on March 14, 2012 at 09:30 pm, said:

Well, I'm happy to say I finally figured it out!

It was the lower control arms. The races that the bushings press into became worn out and just caused the bushing to sit in the arm very loosly. I took the arms off and the bushings just fell out out of them! I put new arms on and the shimmy is gone. Now I need to have a celebratory wheeling trip.

Great! It's usually something simple, just hard to track down and easily missed by many dealers. It's the process of elimination that many don't have the patience, or inclination for...
Good job!

[TJ Jake]

MoparNorm, on March 15, 2012 at 12:27 am, said:

Great! It's usually something simple, just hard to track down and easily missed by many dealers. It's the process of elimination that many don't have the patience, or inclination for...
Good job!

I think I was overlooking the arms because I just replaced the bushings a few months ago. The bushings themselves were fine, but the arms were worn out. I guess all that articulating has taken its toll on them

For now I'll just run the OEM arms. I'm saving up to put Currie arms on it later down the road, that way I will have a durable arm/joint.

[Bob_Sheaves]

You really do not want to do that. Especially if you are going to use polyurethane bushings. Really bad idea.

[MoparNorm]

I agree!
If you have a specific reason for not running the OEM arms (such as adjustable arms, long arms, etc) there are arms that use OEM type rubber bushings and not the Poly bushings. A much, much, better ride quality and much quieter.

[Bob_Sheaves]

....and more durable.