WJ shimmy

[Backwoods Rambler]

Not death wobble...

My WJ is totally stock right now and it has a shimmy in the steering wheel. I just got the firestone lifetime alignment done and it made no change. Also, it still pulls to the right a little. I know I need a new steering stabilizer after my Moab trip.

My thought right now is that I should be concerned about lifting this vehicle if it already has a steering shimmy. The likelyhood is that with my planned KOR 2.75 coil lift, it will turn into a full on death wobble.

Before anyone say it... yes, I'll be taking it back to firestone to get realigned once I get the new SS. OME here I come...

 

[Jeff H]

Is it a bumpsteer like shimmy? Id recommend getting it figured out before the lift. The lift amplifies any issues. I dealt with some major bumpsteer after I installed the lift.

 

[tommudd]

First an alignment will not cause a shimmy/wobble
tire out of balance, loose parts is the first place to look
pulling could be an issue with alignment though are you sure they know what they are doing?
Pulling also could be tire pressure, problem with a belt in that tire, caliper starting to stick, even wheel bearings
I would wait on lifting until you're sure what the problem you now have is.

 

[Backwoods Rambler]

I didn't mean to imply that the alignment caused the shimmy. I know that's not the case because it was there before I did the alignment.

Not like bumpsteer...

It will wobbles ever so slightly, even when going over the smoothest roads. Never gets worse than a very, very, minor shimmy.

 

[Fergie]

Does it shimmy at all speeds, certain speeds, accel/decell? Is it worse after a bump? Did it start after any particular event? Does it get better/worse with the brakes applied?

Could be a bushing in the control arms; could be a TRE; could be an out of round wheel/tire; could be a trackbar bushing; could be a dragging caliper and warped rotor combo.

I would start checking those items out and go from there.

A steering stabilizer has nothing to do with the physical geometry of the steering; it is a creature comfort on vehicles to reduce feedback. A new one SS, or a dual kit from KOR wont fix the issue, but it may mask it enough that you don't care.

Hope you figure it out, took me a while to track down the worn UCA bushing on my 2001 WJ.

Gavin

 

[theksmith]

how many miles on your WJ?

regarding shimmy or DW on Jeeps, and in order from simplest/cheapest to most expensive generally:

loose track bar bracket or track bar bolts
tire rotate & balance (seriously, try another shop, and one with a road-force balancer)
alignment (including everything from caster/camber/toe to funky trackbar/draglink angles that aren't parallel)
ovaled out trackbar mount on the axle side
track bar bushings
control arm bushings
tie rod ends
ball joints
unit-bearings

sometimes one of these things is the silver bullet, but most of the time it's that all of them are already worn just a little bit out of spec just due to a higher mileage vehicle.

if you do a lift and bigger tires, you'll be putting more stress/force on components that are already worn and will most likely get DW. whereas if you get the jeep 100% driving right without a new steering stabilizer even, then you can feel very confident that when you lift it, you won't just be exacerbating existing problems.

 

[Maximus Ram]

Try having the tires balanced and rotated....a tire may even have a busted band, so if you can, try a different set of tires.

 

[Backwoods Rambler]

how many miles on your WJ?

regarding shimmy or DW on Jeeps, and in order from simplest/cheapest to most expensive generally.....

loose track bar bracket or track bar bolts.....

....unit-bearings

sometimes one of these things is the silver bullet, but most of the time it's that all of them are already worn just a little bit out of spec just due to a higher mileage vehicle.

...if you get the jeep 100% driving right without a new steering stabilizer even, then you can feel very confident that when you lift it, you won't just be exacerbating existing problems.

It has just under 99k on it. As far as I could tell, I've put more off road miles on it in 1,500 miles than the previous owners did in 97,000.

The shimmy occurs around 45mph about 75% of the time. I just noticed last night that it does sometimes get a teensie bit worse if its already happening and it hit a bump.

Also, my rear end has a nasty thump. I'm thinking the rear shock bushings. I was going to order the SS and sleeves from KOR, but he doesn't have a secure web site (https://) so I won't order from him. What are my options there guys?

Having never owned a GC, I guess I was curious if a slight shimmy was considered normal?

Thanks for the feedback everyone.

ed: I'm not above masking a hard to find DW issue with a HD SS; but I would prefer to find a solution for it. However, I've heard that can be hard/impossible on GC's.

 

[Backwoods Rambler]

tire rotate & balance (seriously, try another shop, and one with a road-force balancer)

What's so special here?

 

[theksmith]

What's so special here?

just saying some shops do a crap job no matter how many time you take it back, or their machine is out of whack, or whatever, so maybe try a different place.

here's someone explaining the road force balance better than i can: http://www.tundrasolutions.com/forums/1gen-tundra/52821-road-force-balancing/#post407109

none of this may make a difference in your case, but it's a relatively cheap thing to do before you start throwing replacement wear items at the jeep.

 

[Backwoods Rambler]

...none of this may make a difference in your case, but it's a relatively cheap thing to do before you start throwing replacement wear items at the jeep.

:ylsmoke:

 

[Backwoods Rambler]

Road Force Balancing Explained

I will definitely be looking for a road force balance place near me. Thanks :victory:

That explanation was sooo good that a I'm quoting it here:

Road Force Balancing Explained

You have to remove the wheel and tire from the vehicle to have it road force balanced. What the machine does is spin the wheel/tire slowly while pressing a roller against the tread with about 1400 pounds of force. It measures the "loaded runout" of the wheel/tire combination. Then it measures, using other rollers, the runout of the wheel where the bead seats. Then it instructs the user to mark the tire and the wheel, remove them from the machine, break the beads loose, rotate the tires on the wheel to match the marks, then re-inflate and re-mount the wheel/tire on the machine. Then it spins it again to measure the results, then spins it up so balance weights can be applied in the usual manner.

OK, now what's it REALLY doing?

It models the wheel bead mounting surface as a circle that is not necessarily concentric with the rotational axis of the wheel. For the technically literate, that's the first order radial harmonic. It models the tire as a circle that's not necessarily concentric with its beads. It then computes how to mount the tire on the wheel so that the "high spot" of the tire is at the "low spot" of the wheel. Again for the technically literate, it puts the first order harmonic of the tire out of phase with the first order harmonic of the wheel such that they cancel as much as possible.

What that does is minimize the net loaded radial runout of the wheel/tire combination. In layman's terms, it makes the tread surface, under load, as round as possible, relative to the axis of rotation of the wheel.

Does it work? Absolutely. Very expensive machines are used to do the same thing with the tires and wheels that are mounted on new vehicles at the factory. The Hunter GSP9700 does it just as well and it does it in a tire shop. Ask Michelin -- their engineers bought the first six of them Hunter produced.

You can road force balance wheels at any time. I've done it with my own tires at 50,000+ miles. Tires sometimes change their loaded runout with wear, and road force balancing can improve their performance.

-Dan @ www.tundrasolutions.com

 

[wjeeper]

I would defiantly get the shimmy under control before you even think about lifting it. Once I put spacers on my WJ the shimmy turned into full on wobble.

theksmith covered the most common causes I ran into (gave up on WJ's for a cheaper less death wobble prone platform)

Some wobble areas I ran into with my WJ:

• Steering boxes seem to be fairly common to wear out on these. I went through 3 but then again I ran crap Interco tires most of the time (the boxes are WJ specific, I dont know of a real upgrade besides tapping for hydro assist.
• I am convinced stiffening up the the unibody where the steering gear mounts is always a plus on these rigs. Mine flexed quite a bit towards the end (granted I "rock crawled" mine)
• The rubber in the stock control arms seemed really soft and seemed to deteriorate easily.
• If you so much as budget boost and dont put a spacer on the rear wishbone expect that balljoint to wear quickly (mine wore out fast causing some weird wandering)

As it has been said before it could be as simple as one worn out part, or just an almost imprecievable bit of play in several components. Shimmys can turn into wobble, and wobble is a total pain in the *** to get rid of!

p.s. if you need a set of unit bearings you can have an extra set I have. 40K miles, OE, missing studs (yours for shipping if you need them)

 

[wjeeper]

Re-reading your first post it your just feeling it in the steering wheel it could be as simple as a warped set of rotors.........a friend of mines WJ had a "pulsing" you could feel through the wheel and thats all it was for her.

 

[JeffRRC]

re-reading your first post it your just feeling it in the steering wheel it could be as simple as a warped set of rotors.........a friend of mines wj had a "pulsing" you could feel through the wheel and thats all it was for her.

x2