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Discussion Starter #1 (Edited)
I can't figure out what is causing my "flighty/dodgy" steering issue when I go over 45mph

Here's a video of what my front & back end looks like.
3.5" lift came w/ the JKU.
Stock CA's (all 8 of them)
stock driveshaft
35x12.50's tires (really 33.5" diameter however)


What's your opinion? This is much different than death wobble.

 

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I can give you a possible thing to check.

other thsn the deplorable dropped pitman , consider the tires & wheels you're running are much heavier than stock. Now , film from the same camera location but while you're cutting steering lock to lock & wiggle wheel ,with Jeep running but parked , like it is in this video..
I suggest it possible that the stock trackbar is too flimsy & that by videoing it, you'll be able to see it flexing ever so slightly as you crank the steering back n forth. Really work the steering & observe. I've had cheaper aftermarket trackbars flex & cause wander before..

the bushings could just be bad on it or your balljoints could have play, also.

if so , upgrade the trackbar.
 

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I don't see anything obvious. Like you mentioned the draglink and track bar angles look pretty parallel.

My only thought is if the axles and body seem to be not tracking each other, then the trackbars are whats' responsible for the side-to-side rigidity between the frame/body and the axles. And the control arms control the fore/aft movement of the axles So if the connection between the axles and the body seems soft, the nit has to be either a control arm, or track bar issue. In my mind it's much more likely a track bar deal. I've seen some pretty crappy control arm bushings that didn't have much effect, but a little play in the track bar can wreak havoc.

You mentioned that it's much different than death wobble, but I might disagree... Death wobble is just looseness in the suspension components (usually), that sets up a harmonic wobble that self-amplifies. But what if you have the same looseness without the harmonic.... I suspect that's what you are experiencing.

Maybe that is what you get if you have the death wobble, but slap a steering stabilizer bandaid on it. Sloppy loose wandering without the hard wobble.

Just a thought.

I'd start with a hard look at the trackbar, bushings, and mounts (cracked welds/mounts are totally a thing).

I find that having a helper move the steering wheel side-to-side while observing the suspension can help reveal issues where a static look at it sometimes does not show anything. Maybe make a similar video with someone sawing the steering back and forth?

Good luck
 

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If it happens when you roll on or off the gas or touch the brakes in the 35mph-55mph range, my bet is trackbar bushings. My experience, it will get worse to the point where braking in a downhill turn will bring full-on death wobble whereas straight line flat ground just has you scratchin' your head.

Other possibility, don't know how often you hit this road that creates the flightiness, but it could be the road itself. Trucks depress the pavement in two tracks per lane giving a trough for each left or right set of wheels to follow. Your wheel track could have one set of wheel's trying to climb out of this trough, back and forth as you/it search(es) for middle ground. It's most notable in the righthand lane. Low tire pressures will exacerbate the issue.
 

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Recommend:

- go back to stock Pitman
- drag link flip
- front control arm geometry correction brackets
- check / replace ball joints as needed
- get a beefier rear track bar axle bracket

Sent from my LG-H918 using Tapatalk
 

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Random Dude
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At work, not watching the video, so apologies if you mentioned:

Caster angle? <-- yUUUUge possibility - caster is what makes steering re-center / not flighty

Toe-in (or toe-out) = ? <-- can contribute fer shuuure

Also, X2 on everyone who said track bar bushings, control arm bushings, ball joints, unit bearings and Planman's thread

It's a system of interrelated components, time to rule them out 1 by 1 . . . :cwm13:



[insert positivity here] :idea: Congratulations on your opportunity to become a JK suspension & steering guru :thefinger:
 

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Discussion Starter #8
I can give you a possible thing to check.

other thsn the deplorable dropped pitman , consider the tires & wheels you're running are much heavier than stock. Now , film from the same camera location but while you're cutting steering lock to lock & wiggle wheel ,with Jeep running but parked , like it is in this video..
I suggest it possible that the stock trackbar is too flimsy & that by videoing it, you'll be able to see it flexing ever so slightly as you crank the steering back n forth. Really work the steering & observe. I've had cheaper aftermarket trackbars flex & cause wander before..

the bushings could just be bad on it or your balljoints could have play, also.

if so , upgrade the trackbar.
I don't see anything obvious. Like you mentioned the draglink and track bar angles look pretty parallel.

My only thought is if the axles and body seem to be not tracking each other, then the trackbars are whats' responsible for the side-to-side rigidity between the frame/body and the axles. And the control arms control the fore/aft movement of the axles So if the connection between the axles and the body seems soft, the nit has to be either a control arm, or track bar issue. In my mind it's much more likely a track bar deal. I've seen some pretty crappy control arm bushings that didn't have much effect, but a little play in the track bar can wreak havoc.

You mentioned that it's much different than death wobble, but I might disagree... Death wobble is just looseness in the suspension components (usually), that sets up a harmonic wobble that self-amplifies. But what if you have the same looseness without the harmonic.... I suspect that's what you are experiencing.

Maybe that is what you get if you have the death wobble, but slap a steering stabilizer bandaid on it. Sloppy loose wandering without the hard wobble.

Just a thought.

I'd start with a hard look at the trackbar, bushings, and mounts (cracked welds/mounts are totally a thing).

I find that having a helper move the steering wheel side-to-side while observing the suspension can help reveal issues where a static look at it sometimes does not show anything. Maybe make a similar video with someone sawing the steering back and forth?

Good luck
If it happens when you roll on or off the gas or touch the brakes in the 35mph-55mph range, my bet is trackbar bushings. My experience, it will get worse to the point where braking in a downhill turn will bring full-on death wobble whereas straight line flat ground just has you scratchin' your head.

Other possibility, don't know how often you hit this road that creates the flightiness, but it could be the road itself. Trucks depress the pavement in two tracks per lane giving a trough for each left or right set of wheels to follow. Your wheel track could have one set of wheel's trying to climb out of this trough, back and forth as you/it search(es) for middle ground. It's most notable in the righthand lane. Low tire pressures will exacerbate the issue.
I'm no suspension expert, but I would suggest going through @planman thread on death wobble:

https://www.jkowners.com/forum/write-up-dept-library/30723-diagnosing-death-wobble-fixing-non-dw-shimmies-wobbles.html

Maybe it will lead to a clue of what's going on.

Hope this helps... :wink2:
Recommend:

- go back to stock Pitman
- drag link flip
- front control arm geometry correction brackets
- check / replace ball joints as needed
- get a beefier rear track bar axle bracket

Sent from my LG-H918 using Tapatalk
At work, not watching the video, so apologies if you mentioned:

Caster angle? <-- yUUUUge possibility - caster is what makes steering re-center / not flighty

Toe-in (or toe-out) = ? <-- can contribute fer shuuure

Also, X2 on everyone who said track bar bushings, control arm bushings, ball joints, unit bearings and Planman's thread

It's a system of interrelated components, time to rule them out 1 by 1 . . . :cwm13:



[insert positivity here] :idea: Congratulations on your opportunity to become a JK suspension & steering guru :thefinger:
Thanks guys for the feedback. I updated the OP with the picture below. Looks like I need CA's. Also looks like one tire might be a little forward of the other tire :(

 

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Premium Member
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Thanks guys for the feedback. I updated the OP with the picture below. Looks like I need CA's. Also looks like one tire might be a little forward of the other tire :(



If new CAs are too much $$$ at the moment, the geometry correcting brackets work very well (they also help with caster) and are around 1.2 Benjamins.

Sent from my LG-H918 using Tapatalk
 

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Gunnery Sergeant USMC (ret)
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Keep an eye on that front track bar bracket. I used to have a clamp on bracket and it started ripping the metal apart. I had to go to a weld on bracket.
 

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Thanks guys for the feedback. I updated the OP with the picture below. Looks like I need CA's. Also looks like one tire might be a little forward of the other tire :(
I don't see your pic.

If one tire is forward of the other, you need to get that straightened out first. Hard to single out an issue when there are other issues.

Does the odd body roll happen more on one side than the other? Like more roll when turning to the side of the forward tire?
 

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Soon as I read "3.5 lift" and "stock control arms" I knew right away what your issue is..... Needs mo caster.

3.5+ lift you want minimum 5 degrees but preferably 7. This will make the driveline vibrate esp. at higher speeds so you need to figure which is most desireable to you, Less vibrations or better tracking.

Easiest and quickest fix is AEV brackets, they have multiple holes for adjustment and good instructions on how to figure which holes to use. They're also close to being the cheapest out there, Unusual for AEV but they work, Installed many a set.

edit: You can check the caster yourself, Get an angle gauge and a flat spot to park, Set gauge on flat of flange (some pull front driveshaft) and measure, stock JK axles have 6 degrees of caster split between nose and knuckle, So if gauge reads 3, your caster is 3. For 7 you need -1 at pinion, This is why most aftermarket axles have a 10 degree split, better driveline angles.
 

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Yep, like others have said, it needs more caster.

Also, until you get your drag link and track bar even the bump steer will be terrible.

First step, control arms. Next, ditch the drop pitman and do a drag link flip.

Good luck brother.
 
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