Uncontrolled / Unstable After Currie 4" and 35s

[NWPA Jeepy T]

My son's did this. The alignment shop had it on the rack for 5 hours adjusting the track bars and the adjustable control arms. 1000% better now.
Get it into a good shop that does alignments and tracking on lifted vehicles

 

[97TJNM]

Went with 1/8" on 24" aluminum measurements and 3/16" on the tires measurements.

1/8 is good. Probably something else, then.

 

[Mike_H]

Hmm.... I think I mistakenly went the other way and removed torque...

Ok, I think we’re staying the same thing, but to be clear. With the application of anti-seize, you reduced torque on the bolt. That is fine. What I’m saying is to go back through the bolts and give them a little more tightening force, to see if you get easy movement. I mentioned going up by 10 ft pounds or so just to make sure you get some movement in the nut, vs just a click. If you have a bolt that has yielded, but not broken (yet) that little bit of extra torque should snap it.

 

[mrblaine]

Yup - Everything torqued on the ground with the wheels on.

To clarify yet again so this will STOP being posted as the answer to anything except it doesn't matter is you ONLY need to torque the joint bolts with the weight on the axles at ride height if and only IF you are using a control arm joint with a bonded element and bolt sleeve like the factory Clevite bushing. Anything with a ball in races like the JJ doesn't care and it doesn't matter since the ball rotates freely unlike the bolt sleeve in a Clevite bushing.

Also not feeling a 'vibe' from the DS and wheels. I've had both - not enough TC Skid drop so a mild DS vibe before the upgrade. Wheels torqued to 100 ft/lbs.

 

[mrblaine]

It looks like he has a Black Magic Brakes big brake kit. mrblaine will, upon request, drill the new knuckle and tig in a tapered insert so the tie rod can be flipped to the top.

Not always. I order a few pieces of each batch with a straight hole that can be tapered from either direction. The welded insert is only for one where we have to drill out a taper.

 

[JuanTJ]

I had the same issues after I installed a 4in short arm lift and 315s. Definitely have a shop that knows how to do 4x4 alignments do an alignment for you. Also, the tire shop, come to find out, had used bean bags inside the tires instead of weights on the wheels. The wheels were way out of balance. I took it to a different tire shop that was able to properly balance the wheels. Now the ride is very smooth all the way up to 75MPH.

 

[FarFire70]

Did you have an antirock before you moved to 4" + 35s? Are you over correcting too much while driving? Read this from Blaine. This thread is a great read.

https://wranglertjforum.com/threads/steering-wandering-after-currie-antirock-install.18880/

I haven't driven with an antirock before but I don't expect the muscle memory to be the issue. It's touchy even straight on flat roads so I can't see the bodyroll being extreme enough in those conditions to be causing this feel.

Anti-Rock
Caster
You can easily check the caster. Should be at least 5*, but 6.5* is better. The less you have the dart’ier it feels

I'll have to measure it. Guidance in the service manual is pinion takes priority over caster and my pinion is right on with the DS.

 

[FarFire70]

If I can't get this better after another round of checking torques, I'll have to see about a local shop that understands adjustable control arms.

 

[AzJeff]

I'll have to measure it. Guidance in the service manual is pinion takes priority over caster and my pinion is right on with the DS.

If your pinion is in line with your driveshaft with 4" of lift you probably have very little caster. When I bought the '02 in March it had an old 4" Skyjacker lift with adjustable front uppers that someone had all jacked up, it had 0 caster and worn bushings and was undriveable, very darty. This was all new to me and I duplicated the control arm lengths with the new Metalcloak parts and it was still darty, no caster. Got some knowledge here and got it adjusted to 4 degrees of caster and it drives solid to 75. Pinion/DS angles are a few degrees off, so be it. Check your caster.

 

[JMT]

I haven't driven with an antirock before but I don't expect the muscle memory to be the issue. It's touchy even straight on flat roads so I can't see the bodyroll being extreme enough in those conditions to be causing this feel.



I'll have to measure it. Guidance in the service manual is pinion takes priority over caster and my pinion is right on with the DS.

All you need with the front pinion is that you have no vibes, and at full droop there’s no binding. Obviously straight in line will not create vibes if the shaft and joints are all good, but if you lower the pinion you can get some caster back and still be vibe free.

 

[FarFire70]

If your pinion is in line with your driveshaft with 4" of lift you probably have very little caster. When I bought the '02 in March it had an old 4" Skyjacker lift with adjustable front uppers that someone had all jacked up, it had 0 caster and worn bushings and was undriveable, very darty. This was all new to me and I duplicated the control arm lengths with the new Metalcloak parts and it was still darty, no caster. Got some knowledge here and got it adjusted to 4 degrees of caster and it drives solid to 75. Pinion/DS angles are a few degrees off, so be it. Check your caster.

All you need with the front pinion is that you have no vibes, and at full droop there’s no binding. Obviously straight in line will not create vibes if the shaft and joints are all good, but if you lower the pinion you can get some caster back and still be vibe free.

When I first drove it, I was thinking caster. Especially because the steering had some dead-spot feeling to it. And then I found the loose JJ bushing, loose TB bolts, and the unlubed steering and so I doubted that it was caster - especially on the service manual advice.

I hope I mentioned I really was rushing on this to get through emissions before I found all those issues... I usually try not to be sloppy in my auto work. Dedication to the Jeep in July has had be focused on family since so hopping to get some wrenching time this weekend.

I'll be sure to add caster check to the short list again.

 

[TJosh02]

My first thought when reading the thread title was caster was off. Why, because this happened to me by accident. The guy who did the alignment was retiring and was getting sloppy at the end according to my shop guy. He forgot to add loctite to the front upper control arm and after a wheeling trip (2.5hr drive each way) the upper front arm had backed out such that I had negative caster, or at least close to zero. Your description was exactly what it felt like. It was dangerous as all hell to drive. Got it fixed and problem went away.

 

[FarFire70]

I think we're on the right trail with caster being the primary issue!

I plan to wrench tomorrow but I took a minute tonight to pull the ball joint zerk and place the digital angle finder. I'm at 0.1*

 

[FarFire70]

@AzJeff, @JMT, @TJosh02,

You guys called it! Caster. Getting it dialed in to 6.5* made a WORLD of different. Reliably controllable up to 75MPH. Doesn't get jumpy on road bumps. Not floaty and doesn't have the oscillation feeling.

Thanks to everyone in the thread.

Still likely going to take it to a local Jeep dealership who sells modified Jeeps (not many customs shops in my area that I have confidence understand adjustable control arms) just to get a final dial-in.

 

[AzJeff]

Nice! Enjoy all your upgrades.

 

[Longwhitejeep]

Glad you got it sorted!