steering "shim" (wobble)

frequently my steering wheel as I am driving will shim...sometimes when I'm driving straight, around a turn, etc. It comes and then goes....when this happens the jeep does not veer to the left or right....it is just that the steering wheel woobles.....

I know I need new brakes and tires are due but this problem will continue...I have gotten the wheels aligned before and this problem returns....all to quickly after the alignment..

It is a 1998 XJ sport with 125000 miles

What is this and how do I fix it?

does the speed effect it at all, ie does it happen after 45mph? what kind of variables are there?

the wobble can happen at low speeds (30MPH) up to high speeds (70MPH)
when it does wobble it feels worse in a low speed...as if a nut was loosened...and then it will go away if I make a turn or slow down and speed up again

If it happened at about 55 MPH I'd say tire balance, but if it can occur as slow as 30 MPH it's something else. Check for loose ball joints, tie rod ends, track bar, or hub/breaing units.

Also check carefully to ensure that you don't have a bent wheel.

Ray, I just went through the same thing with my '98 XJ 130k miles. Did the alignment, did the rotate & balance, but no help. What I finally found was one bad ball joint and the rubber bushings in the upper & lower control arms were all shot.
HTH :repair:

thanks to all :wave:

I though it may be bushings etc.

I am going to replace them and see because tires are expensive!

because it is stock and doesnt have larger tires, i would look at the tire balance and a new steering stabilizer. new steering stabilizer is only 30$. some will say that a new steering stabilizer will only mask the problem, but on a stock vehicle, it could be the problem.

I run no stabilizer, and mine is as solid as ever. Bushings probably wouldn't cause that, but if you want to replace them, do one arm at a time. Doing the bushings is a pain in the ass, unless you spend more and buy the whole arm from quadratec. I feel certain you have a bad joint, pitman arm, ball, tie rod ends, etc, or really out of balance tires. Jack up the whole front end and play with each tire and get a friend to steer it to inspect for loose joints.

89xj said:

because it is stock and doesnt have larger tires, i would look at the tire balance and a new steering stabilizer. new steering stabilizer is only 30$. some will say that a new steering stabilizer will only mask the problem, but on a stock vehicle, it could be the problem.

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You have no clue, a steering stabzlizer will only mask the problems, I have a 95 stock XJ that I have been running without one for 2 years now. its not needed if all is working correctly

xjnation said:

You have no clue, a steering stabzlizer will only mask the problems, I have a 95 stock XJ that I have been running without one for 2 years now. its not needed if all is working correctly

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x2

xjnation said:

You have no clue, a steering stabzlizer will only mask the problems, I have a 95 stock XJ that I have been running without one for 2 years now. its not needed if all is working correctly

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as i said, it could mask the problem.

but if it is the original stabilizer, it wouldlnt hurt to rule it out also.

should every one just take theirs off and not use one at all?

btw, i do have a clue. no reason to insult me. we all have different opinions.

89xj said:

as i said, it could mask the problem.

but if it is the original stabilizer, it wouldlnt hurt to rule it out also.

should every one just take theirs off and not use one at all?

btw, i do have a clue. no reason to insult me. we all have different opinions.

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I have been working on problems like this probably longer than you have been alive. There is NO possible way a bad stabalizer will cause a shimmy. And replacing the stabalizer will only HIDE other underlying problems.

The steering stabalizer is nothing more than a neutral based shock absorber for the steering system.

If you think it might be the stabalizer take it off and run without and see if anything changes. If any change the problem will be worse.

You are spouting opinions I am posting proven facts

xjnation said:

I have been working on problems like this probably longer than you have been alive. There is NO possible way a bad stabalizer will cause a shimmy. And replacing the stabalizer will only HIDE other underlying problems.

The steering stabalizer is nothing more than a neutral based shock absorber for the steering system.

If you think it might be the stabalizer take it off and run without and see if anything changes. If any change the problem will be worse.

You are spouting opinions I am posting proven facts

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Judging by your birth date of 1960, I can say with confidence that I've been working on cars since before you were born. Age may not provide either of us with sufficient knowledge to understand all there is to know about steering system oscillations. I will accept that the Jeep engineers who designed this thing in the first place had a good reason to include the steering stablilizer. Bean counters and management in any industry will resist changes that increases the cost of production unless there is strong evidence provided by engineering to justify the part or process. If you feel confident is second guessing their opinions, please site a source of information that supports your "proven facts".

The inherent stiffness in the suspension bushings and steering joints, and in particular, the steering box, provide a degree of damping to control steering system oscillations. As these parts wear over time, they are less able to damp out the unwanted oscillations initiated by road damage and/or defects in tires, wheels and brakes. Recognizing that parts wear over time, a stabilizer can add additional damping to the system to provide a margin of safety. Neither a steering stabilizer or worn parts cause the shimmy. Both serve to dampen the oscillations(shimmy).

Removing a part that you suspect is not doing it's job will ensure that it is not doing it's job. The only valid test of the effectiveness of the stabilizer is to replace it with a similar unit known to be good. If the problem is rectified, you can reasonably assume the original was not doing it's job.

[/spout]

MaXJohnson said:

The inherent stiffness in the suspension bushings and steering joints, and in particular, the steering box, provide a degree of damping to control steering system oscillations. As these parts wear over time, they are less able to damp out the unwanted oscillations initiated by road damage and/or defects in tires, wheels and brakes. Recognizing that parts wear over time, a stabilizer can add additional damping to the system to provide a margin of safety. Neither a steering stabilizer or worn parts cause the shimmy. Both serve to dampen the oscillations(shimmy).

Removing a part that you suspect is not doing it's job will ensure that it is not doing it's job. The only valid test of the effectiveness of the stabilizer is to replace it with a similar unit known to be good. If the problem is rectified, you can reasonably assume the original was not doing it's job.

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All true.

However, that doesn't change the fact that a steering stabilizer cannot "cure" a problem, all it can do is dampen oscillations -- in other words, mask the true cause of the problem. I think XJNations's point was (and you said the same thing) that a bad steering stabilizer cannot "cause" steering shimmy. Something else has to cause it, and the only question is whether or not the stabilizer is effective at hiding it.

Eagle said:

All true.

However, that doesn't change the fact that a steering stabilizer cannot "cure" a problem, all it can do is dampen oscillations -- in other words, mask the true cause of the problem. I think XJNations's point was (and you said the same thing) that a bad steering stabilizer cannot "cause" steering shimmy. Something else has to cause it, and the only question is whether or not the stabilizer is effective at hiding it.

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The cause, in the case of an unmodified Jeep, is insufficient damping of the inherent oscillations. The key here is that both the stabilizer and the suspension bushing and steering joints provide damping. How can we say that restoring the damping capability of one is masking the problem while the other is not. The Jeep was engineered under the assumption that both forms of damping were required. The stabilizer was added even though it increases the cost of manufacture.

All spring-mass systems will have a natural frequency at which they will have a tendency to oscillate. If you cannot design the system to keep that natural frequency out of the normal range of operation, the method of control is through the addition of damping. There is a "critical" amount of damping that will allow the system to oscillate through only one cycle and return to a stable state. If the system oscillates past one cycle, it is an indication of insufficient damping. If there is insufficient damping avialable through the suspension and steering links to control the oscillations, additional damping is required through an external device.

MaXJohnson said:

The cause, in the case of an unmodified Jeep, is insufficient damping of the inherent oscillations. The key here is that both the stabilizer and the suspension bushing and steering joints provide damping. How can we say that restoring the damping capability of one is masking the problem while the other is not. The Jeep was engineered under the assumption that both forms of damping were required. The stabilizer was added even though it increases the cost of manufacture.

All spring-mass systems will have a natural frequency at which they will have a tendency to oscillate. If you cannot design the system to keep that natural frequency out of the normal range of operation, the method of control is through the addition of damping. There is a "critical" amount of damping that will allow the system to oscillate through only one cycle and return to a stable state. If the system oscillates past one cycle, it is an indication of insufficient damping. If there is insufficient damping avialable through the suspension and steering links to control the oscillations, additional damping is required through an external device.

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I'm not convinced that damping "inherent" oscillations is the primary reason for the steering damper. What I have always been told, including by the instructors from Jeep at a Jeep 101 several years ago, is that it's to reduce the tendency for the steering wheel to kick back on the driver when negotiating rocky terrain.

If the premise in your second paragraph were 100% applicable, it should (in theory) be impossible to drive an XJ without a steering damper and not have shimmy or even death wobble. Yet many people drive without one, and a lot more probably have a stabilizer that's too worn to do any stablizing. My '88 XJ is a shade over 245,000 miles and I still have the original steering stabilizer on it. It's covered with oil that has leaked out over the years, so I doubt it's doing much except occupying space at this point.

My take is that a vehicle with well balanced tires and a decent alignment won't do anything to start an oscillation, and therefore there will be no oscillation for a steering dampener to dampen. That's why I view the damper as masking the true cause of a shimmy or death wobble. Yes, the damper may slow down the oscillation so that a shimmy doesn't escalate into death wobble ... but the oscillation shouldn't be there in the first place. Something has to CAUSE an oscillation or a shimmy, and a steering damper can't do that. The worst it can do is not hide it.

good gosh, it doesn't make much difference. If you have a shimmy, a stabilizer ain't gonna get rid of it or make it worse, but maybe dial it down a little. Jeep installs them because it is a cheap way to add a tiny bit of stability for idiots who never service and repair their front ends and have all crappy components. Any nitwit who maintains his vehicle and knows how to drive will never need one.

MaXJohnson said:

The cause, in the case of an unmodified Jeep, is insufficient damping of the inherent oscillations. The key here is that both the stabilizer and the suspension bushing and steering joints provide damping. How can we say that restoring the damping capability of one is masking the problem while the other is not. The Jeep was engineered under the assumption that both forms of damping were required. The stabilizer was added even though it increases the cost of manufacture.

All spring-mass systems will have a natural frequency at which they will have a tendency to oscillate. If you cannot design the system to keep that natural frequency out of the normal range of operation, the method of control is through the addition of damping. There is a "critical" amount of damping that will allow the system to oscillate through only one cycle and return to a stable state. If the system oscillates past one cycle, it is an indication of insufficient damping. If there is insufficient damping avialable through the suspension and steering links to control the oscillations, additional damping is required through an external device.

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So you are saying since hundreds of us dont run stabalizers and dont have oscillations that is not needed. Thanks

Eagle said:

I'm not convinced that damping "inherent" oscillations is the primary reason for the steering damper. What I have always been told, including by the instructors from Jeep at a Jeep 101 several years ago, is that it's to reduce the tendency for the steering wheel to kick back on the driver when negotiating rocky terrain.

If the premise in your second paragraph were 100% applicable, it should (in theory) be impossible to drive an XJ without a steering damper and not have shimmy or even death wobble. Yet many people drive without one, and a lot more probably have a stabilizer that's too worn to do any stablizing. My '88 XJ is a shade over 245,000 miles and I still have the original steering stabilizer on it. It's covered with oil that has leaked out over the years, so I doubt it's doing much except occupying space at this point.

My take is that a vehicle with well balanced tires and a decent alignment won't do anything to start an oscillation, and therefore there will be no oscillation for a steering dampener to dampen. That's why I view the damper as masking the true cause of a shimmy or death wobble. Yes, the damper may slow down the oscillation so that a shimmy doesn't escalate into death wobble ... but the oscillation shouldn't be there in the first place. Something has to CAUSE an oscillation or a shimmy, and a steering damper can't do that. The worst it can do is not hide it.

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BAM tell em boss!

Eagle said:

I'm not convinced that damping "inherent" oscillations is the primary reason for the steering damper. What I have always been told, including by the instructors from Jeep at a Jeep 101 several years ago, is that it's to reduce the tendency for the steering wheel to kick back on the driver when negotiating rocky terrain.

If the premise in your second paragraph were 100% applicable, it should (in theory) be impossible to drive an XJ without a steering damper and not have shimmy or even death wobble. Yet many people drive without one, and a lot more probably have a stabilizer that's too worn to do any stablizing. My '88 XJ is a shade over 245,000 miles and I still have the original steering stabilizer on it. It's covered with oil that has leaked out over the years, so I doubt it's doing much except occupying space at this point.

My take is that a vehicle with well balanced tires and a decent alignment won't do anything to start an oscillation, and therefore there will be no oscillation for a steering dampener to dampen. That's why I view the damper as masking the true cause of a shimmy or death wobble. Yes, the damper may slow down the oscillation so that a shimmy doesn't escalate into death wobble ... but the oscillation shouldn't be there in the first place. Something has to CAUSE an oscillation or a shimmy, and a steering damper can't do that. The worst it can do is not hide it.

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Ever wonder why they call it a "stabilizer" instead of a "kick back tendancy reducer"?

Your Jeep 101 instructor could have said:

"Our product has an inherent design flaw that will, as the components wear, result in an uncontrollable shimmy. We add the steering stabilizer as a safety margin to over damp the system. This helps protect owners with poor maintenance habits, thus lowering our liability".

I doubt he'd want a statement like that to get back to his superiors. CYA !

The stiffness inherent in all new steering and suspension components is sufficient to provide the critical damping necessary to control the expected oscillations. It is when these components wear that the added damping of the stabillizer is necessary. Without wear, the stabilizer is superfluous, but wear is inevitable. As XJnation points out, if everything is in great shape, you can run without a stabilizer and never miss it. The problem is keeping everything in great shape on a 200,000 mile Jeep.

An out of balance tire is only one of several triggers that will start this oscillation. Bad tire construction, a bent wheel, warped brake rotor and of course road damage or expansion joints. These are all triggers, not causes. The cause is the combination of mass and effective spring rate that results in a natural frequency falling within the operating range of the vehicle.

The cause: the natural tendancy for a spring/mass system to oscillate at a specific frequency
The trigger: wheel balance or tire/wheel/brake design flaws, road irregularities
The resisting force: damping provided by steering and suspension components and steering stabilizer