What have I done... (diagnosing severe wobble but not DW)

[Bonanza]

12/6/22-- New ball joints and tires eliminated most wobbling. Since adding metalcloak steering brace, I've experienced no wobble, even on cold mornings and actively trying to initiate a wobble.

After going through all of the below, my wobbling, induced by hitting a pothole or similar road imperfection, was almost certainly made possible by the tires, the ball joints, or a combination thereof. The addition of the metalcloak brace has also helped significantly, which leads me to think there is play at the steering sector shaft that could have helped introduce play into the system.

[Original Post]

Well well well. I did something, or uncovered something, but I'm not sure what. I have a JKS 3.5" lift. The other day I replaced a bump stop, AND I added a 3/4" spacer to level the Jeep a bit. Visually, it didn't seem to change much. Now I'm getting a terrible wobble in the morning. Not a death wobble, but a sever shaking that I can speed out of. I've had DW before and this isn't it. I'm wondering what I did. I'm going to post an update when I find the culprit to aid future searchers.

TRIGGER event-- Cold/Cool morning, 30-45 mph, driving over small imperfection in the road with the right side front tire. Wobble less severe after some driving, and becomes normal bump steer in the afternoon.
DESCRIPTION-- Sever wobble (not shimmy), but not full blown DW. Can speed out.
MILES- 15k, all on 37s and lift

Hypothesis-- right now, I suspect LCA bushings on passenger side. Possibly a change to castor angle triggering the event.
Edit1- not castor. LCA and drag link end at pitman arm suspects #1 and #2

Track bar?

I have an adjustable track bar, JKS. AFTER I installed the spacers, I loosened and tightened the track bar and LCAs on the ground. For the track bar, I used a breaker bar to the point it was bending, so I can't imagine it can get any tighter. I do have a steering stabilizer bracket that uses the track bar hole, but everything was fine before the spacers, so I don't think that's it. I also think the TB is preventing full on wobble.

Feedback-- Potentially too tight. Tightened track bar, I don't suspect this was the issue

LCAs?

I have non-OE LCAs, and they're tight too. BUT-- I can hand wiggle one of them, and I'm not sure if the bushing has gone bad. I'm going to pull it off and inspect it. They're tight at the bolts but have movement in the bushings.

Feedback-- despite feeling tight, might not be torqued to spec. FCA uses Torque + additional angle.

edit- wobble not caused by LCAs.

Castor?

Before the spacers, no problem. Raising it 3/4"...? Not sure. Going to put my angle finder on it and get a good reading. I didn't re-adjust the LCA after the spacers, but the castor isn't the CAUSE of wobble, it just might trigger it.

Feedback-- 3/4" spacer added on top of a 3.5" lift isn't the same castor change as a spacer added to a stock spring. Possible that castor is out of spec due to exponential change that castor endures as lift increases.

edit- pinion angle 0.5, putting castor at 6 or 6.5”. Not Castor angle.

Alignment?

I just realigned the Jeep at home not long ago. slight toe-in, 1/16". Before the spacers, no problem. I don't believe the alignment is CAUSING the wobble, and I don't think it is triggering it, either.

Ball Joints?

Stock. I have new ones waiting to go in when I do my gears. I suspect these are blown out.

Edit-- they were not "blown out", but replacements yielded significant improvement.

Feedback-- rock tires at 12+6, 9+3 to check for issues.
Edit- did this. Revealed play in drag link at pitman arm, no knocking or transmission of contact at ball joints or knuckle.

Tires?

Maybe the trigger, not the cause. Cold morning, 37s, might flat spot. But no speed-reliant shimmy. Perfect wear. 35-36 PSI all around, before and after spacers.

Replaced tires with 37" Baja Boss ATs. No wobble to report.

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[j.o.y.ride]

Track bar?

I have an adjustable track bar, JKS. AFTER I installed the spacers, I loosened and tightened the track bar and LCAs on the ground. For the track bar, I used a breaker bar to the point it was bending, so I can't imagine it can get any tighter. I do have a steering stabilizer bracket that uses the track bar hole, but everything was fine before the spacers, so I don't think that's it. I also think the TB is preventing full on wobble.

So you don't have a torque wrench? Then how do you know the rest of the bolts are torqued properly? And the track bar torque is 110lbs, shouldn't be bending breaker bars.

LCAs?

I have non-OE LCAs, and they're tight too. BUT-- I can hand wiggle one of them, and I'm not sure if the bushing has gone bad. I'm going to pull it off and inspect it. They're tight at the bolts but have movement in the bushings.

You should not be able to wiggle your control arms. Movement in bushings by hand should be really minimal, if they're floppy they're bad. Or they aren't tightened enough... see above re: torque wrench. These lowers are 190lbs, pretty heavy.

As for alignment? Sure, you lifted it a bit and didn't realign. But I would look to proper torque and wiggly control arms first.

 

[Bonanza]

So you don't have a torque wrench? Then how do you know the rest of the bolts are torqued properly? And the track bar torque is 110lbs, shouldn't be bending breaker bars.

You should not be able to wiggle your control arms. Movement in bushings by hand should be really minimal, if they're floppy they're bad. Or they aren't tightened enough... see above re: torque wrench. These lowers are 190lbs, pretty heavy.

As for alignment? Sure, you lifted it a bit and didn't realign. But I would look to proper torque and wiggly control arms first.

My concern with the Trackbar is the SS bracket between the bolt and the TB bracket. My LCA pivots a bit, but on bushing. I'll hit it with a torque wrench and see if that helps any.

 

[j.o.y.ride]

I don't really follow what you're saying maybe somebody else does but maybe pictures of the track bar will help

 

[Bonanza]

I don't really follow what you're saying maybe somebody else does but maybe pictures of the track bar will help

The relocation bracket for the SS uses the track bar hole. It acts like a huge washer, so to speak, so I was concerned the torque value from stock might vary, because there is an impact on the clamping force from the SS bracket in the way.

 

[Rahkmalla]

I used a breaker bar to the point it was bending, so I can't imagine it can get any tighter.

"I can't imagine it can get any tighter" can't possibly be the correct torque spec for that part. If you've done all your mods without a torque wrench then the list of possible problems here is about a mile long. a breaker bar is not a torque wrench. an impact is not a torque wrench. Even an impact with a torque stik is not a torque wrench.

 

[MPMB]

Did you take the wheels off when you did the work?

Jack front of the truck up until the wheels are just off the ground. On each side, put your hands at 9 & 3 and push the tire in a rocking motion. Then do 12 and 6. If there's a wiggle, that will narrow your options down.

Track bars usually don't cause a wiggle/wobble, unless the mounts are broken or it wasn't tightened. Most wobbles are ball joints/steering/wheel/tire related.

 

[ShadowsPapa]

Well well well. I did something, or uncovered something, but I'm not sure what. I have a JKS 3.5" lift. The other day I replaced a bump stop, AND I added a 3/4" spacer to level the Jeep a bit. Visually, it didn't seem to change much. Now I'm getting a terrible wobble in the morning. Not a death wobble, but a sever shaking that I can speed out of. I've had DW before and this isn't it. I'm wondering what I did. I'm going to post an update when I find the culprit to aid future searchers.

TRIGGER event-- Cold/Cool morning, 30-45 mph, driving over small imperfection in the road with the right side front tire. Wobble less severe after some driving, and becomes normal bump steer in the afternoon.
DESCRIPTION-- Sever wobble (not shimmy), but not full blown DW. Can speed out.
MILES- 15k, all on 37s and lift

Hypothesis-- right now, I suspect LCA bushings on passenger side. Possibly a change to castor angle triggering the event.

Track bar?

I have an adjustable track bar, JKS. AFTER I installed the spacers, I loosened and tightened the track bar and LCAs on the ground. For the track bar, I used a breaker bar to the point it was bending, so I can't imagine it can get any tighter. I do have a steering stabilizer bracket that uses the track bar hole, but everything was fine before the spacers, so I don't think that's it. I also think the TB is preventing full on wobble.

LCAs?

I have non-OE LCAs, and they're tight too. BUT-- I can hand wiggle one of them, and I'm not sure if the bushing has gone bad. I'm going to pull it off and inspect it. They're tight at the bolts but have movement in the bushings.

Castor?

Before the spacers, no problem. Raising it 3/4"...? Not sure. Going to put my angle finder on it and get a good reading. I didn't re-adjust the LCA after the spacers, but the castor isn't the CAUSE of wobble, it just might trigger it.

Alignment?

I just realigned the Jeep at home not long ago. Before the spacers, no problem. I don't believe the alignment is CAUSING the wobble, and I don't think it is triggering it, either.

Ball Joints?

Stock. I have new ones waiting to go in when I do my gears. I suspect these are blown out.

Tires?

Maybe the trigger, not the cause. Cold morning, 37s, might flat spot. But no speed-reliant shimmy. Perfect wear. 35-36 PSI all around, before and after spacers.

What do you all think? I'm going to post an update later to aid future users to diagnose a similar event.

When you lift a vehicle with this type of suspension, even with SLA IFS, the first bit of lift changes caster some, the next inch changes caster to a greater degree, the more you lift, the greater caster change per inch. Just for easy numbers, if the first 2" changed caster 3/4" of a degree, the next 1" may change it nearly that much because the arms swing in an arc, My very minor 1" or so lift changed caster a tiny bit, still in specs. I'd expect if I changed it another 2" it would be way out. Caster changes on a curve, not a straight line, for each inch you lift it. The 3rd or 4th inch changes it a lot more than the first inch did, or the 2nd inch.

 

[ShadowsPapa]

I'll leave my other post about caster......

Make sure you use the correct specs for torque and torque things with wheels on and planted on the ground. Never tighten suspension parts with it's feet hanging in the air.
Also - I have some specs I got recently from a dealer that are a lot different than the specs floating around that I think someone said came from a lift kit.
Several bolts are torque plus angle (TA) - if you read the science of bolt torque and clamping force, you'll see what that's not just important, it's critical. I have the images in the house on another PC and I'm trying to clean them up to read them.
I can't recall which were TA specs, I think trackbar may have been one of them.
For the rears, both upper and lower control arm front and rear bolts are TA (Torque plus Angle)

 

[MPMB]

Several bolts are torque plus angle (TA) - if you read the science of bolt torque and clamping force, you'll see what that's not just important, it's critical. I have the images in the house on another PC and I'm trying to clean them up to read them.
I can't recall which were TA specs, I think trackbar may have been one of them.
For the rears, both upper and lower control arm front and rear bolts are TA (Torque plus Angle)

You referring to the angle the bars/LCAs must be when torquing parts? Moment centers & roll centers?

 

[Bonanza]

I'll leave my other post about caster......

Make sure you use the correct specs for torque and torque things with wheels on and planted on the ground. Never tighten suspension parts with it's feet hanging in the air.
Also - I have some specs I got recently from a dealer that are a lot different than the specs floating around that I think someone said came from a lift kit.
Several bolts are torque plus angle (TA) - if you read the science of bolt torque and clamping force, you'll see what that's not just important, it's critical. I have the images in the house on another PC and I'm trying to clean them up to read them.
I can't recall which were TA specs, I think trackbar may have been one of them.
For the rears, both upper and lower control arm front and rear bolts are TA (Torque plus Angle)

I tightened everything on the ground. I've worked on cars a long time and haven't heard of torgue plus angle. Hmm.

 

[Bonanza]

Did you take the wheels off when you did the work?

Jack front of the truck up until the wheels are just off the ground. On each side, put your hands at 9 & 3 and push the tire in a rocking motion. Then do 12 and 6. If there's a wiggle, that will narrow your options down.

Track bars usually don't cause a wiggle/wobble, unless the mounts are broken or it wasn't tightened. Most wobbles are ball joints/steering/wheel/tire related.

I'll do this and report back.

 

[j.o.y.ride]

The relocation bracket for the SS uses the track bar hole. It acts like a huge washer, so to speak, so I was concerned the torque value from stock might vary, because there is an impact on the clamping force from the SS bracket in the way.

Oh gotcha. Well torque is torque. I would suggest you reset all your bolts to proper values, including the ones that may be way over tightened.

 

[Bonanza]

"I can't imagine it can get any tighter" can't possibly be the correct torque spec for that part. If you've done all your mods without a torque wrench then the list of possible problems here is about a mile long. a breaker bar is not a torque wrench. an impact is not a torque wrench. Even an impact with a torque stik is not a torque wrench.

True. But what I attempted to do was nullify an issue of a track bar bolt not being tight enough. I can't physically tighten it any more without breaking the bolt or bending the breaker bar.

 

[Rahkmalla]

I'll leave my other post about caster......

Make sure you use the correct specs for torque and torque things with wheels on and planted on the ground. Never tighten suspension parts with it's feet hanging in the air.
Also - I have some specs I got recently from a dealer that are a lot different than the specs floating around that I think someone said came from a lift kit.
Several bolts are torque plus angle (TA) - if you read the science of bolt torque and clamping force, you'll see what that's not just important, it's critical. I have the images in the house on another PC and I'm trying to clean them up to read them.
I can't recall which were TA specs, I think trackbar may have been one of them.
For the rears, both upper and lower control arm front and rear bolts are TA (Torque plus Angle)

Where does even get their hands on torque specs anymore? Seems Haynes and Chilton are a relic of the past.

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