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Jeep unstable at normal driving speeds

Tpink1234

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Jan 5, 2022
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Arizona
My dads Jeep is unstable at 40+mph while mine is perfect stable at 80. We both have 4.5” lifts, anti rock sway bars 35s the only difference is the control arms we went with. Both caster and pinion angle it set very very similar to each other and have messed with his 15+ times seeing if it will help and sadly it has not. The only difference between Jeeps is I have core 4x4 control arms with Johnny joints all around and he went with metal cloak flex joints. I’m starting to wonder if the metal cloaks are causing the problem. Has anyone else heard of this being a problem?
 
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Blackjack

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My dads Jeep is unstable at 40+mph while mine is perfect stable at 80. We both have 4.5” lifts, anti rock sway bars 35s the only difference is the control arms we went with. Both caster and pinion angle it set very very similar to each other and have messed with his 15+ times seeing if it will help and sadly it has not. The only difference between Jeeps is I have core 4x4 control arms with Johnny joints all around and he went with metal cloak flex joints. I’m starting to wonder if the metal cloaks are causing the problem. Has anyone else heard of this being a problem?

Before you condemn the arms there are a few other things to look at. You checked caster but what is your toe in set at? Are all the steering linkage, trackbars and the like in good working order? Are you running the same tires/wheels and if not have you tried swapping them to see if something changes?
 

Necro

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Jun 22, 2022
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Norfolk Virginia
Have you checked to see if any of the arm mounts are cracked or broken? Sometimes they break in such a way that when the Jeep is sitting still it isnt obvious.
 

jjvw

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A little like @Blackjack says those arms are pretty low on the list of possible issues. Alignment numbers, tires/pressure and shocks seem like more important things.

While even I wouldn't go so far as to say that MC bushings will make a Jeep anything close to unstable, I do have direct experience with a rig whose overall tightness and handling noticably improved after swapping out low mileage MC arms to a new set of Savvy arms with JJ's.
 
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TRE3TOP

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Oct 25, 2020
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Atlanta
Throw ball joints, wheel bearings and tie rods ends into the list of things to check for excessive wear as well.
 
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Tpink1234

Tpink1234

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Jan 5, 2022
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Location
Arizona
Before you condemn the arms there are a few other things to look at. You checked caster but what is your toe in set at? Are all the steering linkage, trackbars and the like in good working order? Are you running the same tires/wheels and if not have you tried swapping them to see if something changes?

I tried swapping the wheels/tires messed with caster set it to numbers people say makes their Jeep ride perfectly. Just strange how easily I made my Jeep drive perfectly and can’t seem to figure his out.
 

CharlesHS

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Steering shaft coupler is something I have not checked out is there a way to see if it’s warn out?

Have someone assist you by turning the steering wheel and then looking at the steering shaft that is attached to the steering box; you can judge by how much the steering wheel turns before the steering shaft turns.
You can examine the steering coupling for play while the steering wheel is turned.
 

Krusty_tub

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Apr 23, 2022
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Ct
Was the toe ever set after the lift? That is the most common "unstable" I've seen these Go-Karts get
 

Macrosill

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I just changed trac bar, steering stabilizer, drag link, pitman arm, tie rod and tie rod ends. Took it for a test drive and it was "unstable". Felt like it would wander all over the place. Did a DIY alignment and it made a world of difference. I had 3" toe out. Set it to 1/8 " toe in and all was well. Check your toe in.
 

AndyG

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I can tell you’re mechanically inclined enough to get it sorted out- All the above posts are valuable and the only thing I have to offer is don’t be surprised if it is just the smallest change- be persistent and hide your keys so he doesn’t take yours.
 

AndyG

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My first two guesses would be a bad toe-in angle or insufficient caster angle.

I had a TJ that I was fighting getting consistent toe in- It had 90,000 miles


The 35 inch tires and abuse by the kid that had it had the hub unit bearings so worn that getting it set correctly was hopeless and in addition to incorrect toe It drove terrible. I don’t think it did anything right.
 
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