Looking for help identifying steering issue on un-modified Comanche.

[Jerry]

Howdy fellas.

As thread title, looking for input on my wayward MJ.

The symptom is a sudden turn in on high speed corners (60mph+) resulting in what I can best describe as a 'weave'. It tracks true, hands off the wheel braking it's all good, brakes in straight line no issues. It's only at higher speeds the problem shows up and only in RH corners.

I'll try my best to describe it:
Rolling along at anything above 60mph I'll turn into a corner and it's fine but as I increase the turn angle there's a point when it suddenly turns in hard like I've yanked the steering hard but I haven't. This then develops into a weave as I correct it and the cycle continues until I slow down or straighten up. Boing boing boing aaarg  :eek:  :eek: 

I've checked all the suspension joints as best I can without a hoist and nothing appears loose or worn.

The truck is totally stock, no lift or big tires, nuffin'.

I rotated the tires recently to rule them out too.

Any ideas guys?

Thanks in advance :)

[AeroNautical]

Sounds like a worn tie rod end on the RH side. You may not be able to wiggle it by hand, but under the load of the truck in a turn, it might wiggle enough to cause a shimmy or sudden yank. 

[Eagle]

Toe-in isn't set correctly.

[Jerry]

Cool I'll investigate those two items. 

Thanks for the input :)

[Jerry]

Thread bump ...

Hi guys :)

So after getting a shop to check out all the steering angles it turns out that it's all good except the RH caster angle is @ +10° instead of the factory spec 4° it should be. Progress! I now have a good idea what's causing my shimmy. It seems I have a minor case of "death wobble"!

The guys at the shop said the caster angle is non adjustable and they can't help but I've done some CC forum searching and read that you can get shims to make caster angle adjustments. Is that right? If so can somebody post a photo showing where the shims go? And, am I'm barking up the right tree here?

PS. All bad joints and bushings have been replaced now to try and eliminate them as a cause.

Thanks :)

[shelbyluvv]

Go to a different alignment shop ASAP. They don't know what they're doing.

 

http://www.cherokeetalk.com/forum/f8/there-caster-adjustment-xj-12836/

 

http://jeep-xj.info/HowtoAlignment.htm

[Jerry]

Thanks Mr Shelby.

I'll check that out AND find another shop! :)

[HOrnbrod]

The factory caster spec is 7.5* positive. If you are at  +10* on the right side, all you have to do is remove some shims from the pocket behind the right LCA. Also, you can check your own caster with a simple angle finder on the upper ball joint flat. Both sides need to be the same as close to 7.5* as possible. More shims = more + angle, and vice-versa. See this thead:

 

  http://comancheclub.com/topic/45885-adjusting-caster/?hl=angle+finder

[Jerry]

Thanks for the info hornbrod, very helpful.