BlackXJay

So I had a death wobble issue a few months back.

99 4wd xj
242 tcase
149k
31x10.5x15
3 inch lift with 3/4 inch spacers

Replaced all this

-Shock bushings on new shocks with pin bar eliminator
-Ironman adjustable upper and lower control arms
-Dana u-joints at the axle
-RC adjustable track bar (checked all bolts and wear)
-Dana upper and lower ball joints
-New sway bar bushings
-New timken wheel hub assembly
-Moog ZJ tie rod with all new ends
-New Drag link end
-RC steering stabilizer

Checked all bolts for proper torque
Checked tires 32.5 psi
Had an alignment to 1/8 inch toe in

Everything was fine for a few months. Probably since the fall. Now the wobble is back with vengeance at 45 mph when I hit a bump.

So I rechecked everything and all seems fine. Checked every bolt torque and bushing.

Could I somehow went out of alignment or maybe the wheels need to be balanced? I'm at a loss.

tech

Did you remove the RC steering stabilizer to check it ? and what was your caster set at ?

BlackXJay

I have not taken the steering stabilizer out to check it. It is about 2 years old and I never thought it would go bad in that time but I will remove it and try to compress it. The caster was in spec at my last alignment I do not have the print out but I am going to get another alignment this week and post up a print out

Martlor13

the sterring stabilizer shouldnt cause death wobble. It can help mask it, but i dont think its a primary source at all to cause death wobble. Quite a few people actually dont even use one.

PatHenry

x2 - Trackbar is the usual suspect, but in your case may not be. Check the frame and axle mounts for cracking if you haven't already.
Another thing that is often overlooked in DW is the steering gear. I'm not sure what the diagnostic procedure is on that though.

BlackXJay

I've checked for cracking at the frame and axle mounts. All good.

But I had an alignment done and came back with higher then spec caster #s. Somewhere around 9 degrees. I'll post up the spec sheet tonight bc I have a few questions maybe someone can answer. Thanks

BlackXJay

Okay here is the print out. It seems my toe was not in spec.

So a few questions. Can any of the before numbers cause death wobble?

Ive read most people have their caster from 5-7 degrees and say higher. Is that the number i am shooting for?

The spec limit for camber is 0-.5
I am at .9 i just replaced the ball joints and wheel hubs literally 3 weeks ago. Its never really been wheeled to bend an axle shaft. Never had a problem with uneven wear on tires.....does caster effect camber in any way and am i that badly out of spec to start looking for offset ball joints?

Thanks

jordan96xj

Your actual caster is higher than the highest value in the range give by the FSM (manual). Ideal is 7.0 (range of 5.25-8.5). Yours is nearly an entire degree higher than the highest value in the range.


Caster that is not close to spec can definitely contribute to steering problems and death wobble (consider those wheels on the shopping carts that oscillate rapidly side to side as you push the cart, that is what proper caster tries to prevent).

BlackXJay

Okay well this weekend I guess I'll be adjusting my lower control arms. I used the eye to eye measurements I was given for my lift but I guess that cant be an exact science.
Now to lower caster will I be shortening or lengthening the LCA's. If anyone knows off hand it'll save me some trial and error.

Also what is the best way to see what your caster angle is without me getting another alignment. I have a magnetic angle finder if that helps.

jordan96xj

Tilting the top of the steering knuckle forward provides negative caster. So it would seem that you should shorten your lower control arms.


You can lookup measuring caster on youtube. I'm sure you could fashion a way to do it at home, but by the time it is said and done it may be easier to just get the alignment checked. Keep in mind that some shops differentiate between "checking" the alignment (getting a printout) and "performing" an alignment. Make sure to ask.