Small bump whobble

[Utah_jeepster]

Ok I am tracking down a small whobble I get from the steering wheel when I hit small bumps in the road.
First the details...2001 TJ with 4 inch lift long arm. 35' tires at full pressure/ rims are ok with no cracks. Just been balanced and rotated less than a month ago.
Checked the wheel bearings/axle shafts for play (none).
The U-Joints look fine with no seperation or gaps(did not pull them apart to see).
I do have a crushed upper end track bar boot and can move the bar fowards and backwards some. I think I need to replace the upper and lower bushings on the track bar and that might be where my problem is.

Yes ? no? suggestions?

 

[phatyaspen]

Deep Water Blues!

track bar drop...

 

[Tug-n-pull]

L33TJ33P aka Jason was have some sort of shake shimmy or some thing like you are speaking of recently. He told me a good Steerin Stablizer did all the trick to make it steady again. Talk to him if you get a chance. tug

 

[Snitty]

Need help buying a new soft top

it could very well be the tracbar

 

[L33TJ33P]

Bumpsteer/Death Wobble is SUCH a pain in the butt to get ironed out. Alighnment, Balance, Trackbar, Stabilizer, Brake Rotors, Even simple Tire rotation, can fix your "bumpsteer" All it is a SOMETHING in your Steering that causes it. I have succesesfully Calmed mine down but that is all I haven't gotten rid of it.

Through my research to rid myself of this plague I have read many, MANY, people that have had it and actually cured it, and most of then were different. It is a REAL pain in the arse but you get some good technical knowledge as you try to figure it out.

Here is a site that will give you a few things to try.

http://www.off-road.com/jeep/tech/deathwobble/

The first "Real" person I asked face to face said Stabilizer (the factory crap is just that, CRAP)

Right now I think mine will finally go away after I get my new meats. The GSA's have been quoted as to causing this problem by a FEW TJ/XJ/Coil suspension folks.

Hope it helps. I will let you know everything I find. So far I can actually make it happen on command. but here is the list of what I have done.

Alignment Helped but didn't cure
Rotation Helped a little more
Shocks Helped a little more
Stabilizer made it not so hair raising (careful here, Beefier stabilizer is mearly a coverup, not a fix)

What I have left to try
New Trakbar (adjustable for future use)
new Tires and wheels (planned anyway)
re-align (Shadetree type)***
Caster re-set (2" lift should NOT effect this but what the hay, maybe it will fix it)



P.S. your meats can and will cause it. Even something so small as a little mud getting shoved behind a weight and a bit of crusty mud on the inside of the Rims. DW/Bumpsteer is a curse and I feel sorry for ANYONE that goes through what I have been through. If you don't get it fixed it can get worse and make you mess up your clothes if yer not expecting it.


***: Shadetree Alignment is pretty easy. The "Toe-in" should be 1/8 to 1/4 inch "Toe-In" Find your Mold line on your front tires and measure them Align them by making the rear mold line 1/8 to 1/4 inch wider than the front. I can go into more detail if you don't understand.

 

[Bounty__Hunter]

DEATH WOBBLE is not the same as BUMPSTEER.

Death Wobble (DW) is the violent shaking of the front end and steering wheel when a given speed is reached, and usually only cured by slowing to a near stop.

Bumpsteer is the turning of the steering wheel when both wheels of the front axle encounter a bump at the same time. Slowly hit a speedbump while loosely gripping the steering wheel will determine if you have bumpsteer.

DW is a major headache, and as mentioned above, has no cut and dry fix, usually a combination of things. I see it most often with 4" and larger lifts with stock control arms. You need longer adjustible lower control arms for the correct suspension geometry. There are many other causes of DW, the steering stabilizer being the least likely cause.

Bumpsteer is caused by the front track bar not being parallel to the draglink, most common after a lift is installed. I don't recommend the brackets that lower the lower track bar mount, this only increases the angle of the trackbar, not good. Our lifted XJ had this bracket on it when we bought it, 3" lift, and it had terrible bumpsteer. I removed the bracket and redrilled the lower track bar hole about .5" to the driver's side. This brought the trackbar back parrallel with the steering and cured my bumpsteer.

 

[Utah_jeepster]

Hey tug I might be moving near you!!!!!

Spent an hour over lunch and replaced both the lower bushing and the upper ball joint. Shot her with the laser tracker to make sure the axle is with center line of the frame. (it is now with in .010 of true center line)
Yes I know using a 1/4 mil laser tracker is anal but I am a machinist ...lol.
The drive home was smooth as glass.
Please note to all the track bar should be solid and shouldnt be able to be moved by hand. The only movment it should show is when you raise and lower your axle. Since the lower bushing allowed the whole axle to move slightly when one wheel hit a bump I got some wobble feed back through the steering wheel as the axle refound center again.