I've had my 2012 two-door JK Rubicon to the shop three time as we're trying to fix a death wobble issue. Can't figure it out. Wobbles very apparent from 45 mph up to ~60 mph, especially hitting a bump within those ranges. Crippling DW occurs—have to slow to a stop for it to go away.

I've looked at planman's material.

History:
• Moderately offroaded about ten times, but never thrashed...
• RK 2.5" Max Travel kit installed with OME shocks (stock driveshafts), with LCAs and track bar set to RK's specs
• Stock SS replaced with Superlift SS kit that brings it up above the tie rod
• All greasable fittings are greased
• Ball joints are good
• Vehicle and stock 32" KM2 tires have 38k miles on them, five-tire rotated every 5k miles
• Axle-side track bar bracket had Grade 8 washers welded to each side of the track bar mounting hole to sure-up the oblonged hole

1.) First time to shop: brought it in first time for an alignment and to check all suspension/steering joints, mounting bolts, and jam nuts. Frame-side track bar bolt found to be loose and tightened. Everything else is fine. Jeep aligned and caster is about 6º. Toe brought in to ~1/8". Still had the problems.

2.) Second time to shop: check everything again, and they want to get the caster to the stock 3º or so. The toe was out again this time in the alignment, brought it back in to ~1/8". I mentioned that the knuckle-side drag link joint moved slightly up and down when cycling the steering: was assured that the amount of movement was normal and not to worry (I'm worried this is seeding the problem).

3.) Relunctantly let them install cam bolts on the axle-side lower control arm mounts to bring the caster back to around 3º. Not sure if this is going to negatively affect my front driveshaft, even though I reminded them that it's a CV design. They assured me it's fine. Already having adjustable LCAs, I was very hesitant to let them put another point of adjustment in that area, especially since I crawl in the rocks and a lot of force is exerted for things to get bumped out of spec. The tech also removed my SS while doing this and noticed that the middle 3–4" of travel offered no resistance at all—only when you got the shaft to the extended or compressed positions would it offer any resistance.

It drives fines now, but I still get vibes from 45–55 mph. It doesn't seem that it goes into full-on DW mode as much anymore, but it's gotten close twice and I just hate always having to worry about needing to have a way out on the highway so I can pull over. I just don't know what else to do.

My last ditch efforts are to rotate the tires (they're due anyway), get them balanced, replace the drag link with something beefier (at least replace the knuck-side joint/shaft), and throw on a dual steering stabilizer setup like Superlift's to dampen vibes that seed the DW.

I know these DW issues are common and require just going through everything that can cause them, but this one is pissing me off—I'd like to get things ironed out before I go to 37s.

Thanks for the help.

 

Not understanding why the cam bolts if you have adjustable control arms. The vibration at 45-55 sounds like a balance issue. Also check you track bar hole where the bolt was loose to make sure it's not oblong.

 

I feel your pain, I haven't had DW in a while but anytime I feel a slight twitch of the steering wheel I am preparing for the worst. 45/55 mph sounds more tire issues.

My draglink moved a little so I replaced(easy and cheap), If you are planning on going 37s then you probably have big enough lift and should do draglink flip anyway.

 

if it were me i would first go get tires balanced....drive it...if u get more dw take it straight to tire shop and recheck balance...if u have thrown off a weight or the tires wont balance well i would say thats ur problem...if balance is good then u can atleast rule that out...

 

That was my exact question to the techs at the shop, "if my LCAs are adjustable length to dial in the correct pinion angle/caster, why do I need another point of adjustment?" They explained to me that it was to adjust the angle at which the LCA interfaces with the axle: they were looking to move up the mounting bolt hole on the axle-side. Think along the lines of AEV's CA brackets—instead of bringing the frame-side CA mounting holes down, the cam bolts brang the axle-side mounting bolts up. It's makes sense in my head, but I was still relunctant because I was afraid of throwing the cam bolts out of adjustment offroad. And it didn't alieviate the problem anyway. Doing the cam bolts, they got my caster from 6º to 3º, roughly. RK suggests to keep the caster around 6º, which is what it was before they started messing with it, and it still had the DW. After doing it, it's back to the stock 3º figure... and I'm unsure about the driveshaft damage implications of doing that.

The ONLY thing I haven't done yet is balance the tires, which was stupid, but since I'm getting 37s as soon as I sell my motorcycle, I didn't want to waste the money on that. I'm going to do it anyway after I put the dual SS setup on if the bike doesn't sell soon.

I think that's my plan for the time being.


Thanks for the input., everyone. Any further thoughts are welcome, of course...

 

I went through the same thing to find out my bolt holes on the frame for the LCAs were slightly wallowed out. welded some thick washers on both sides and havnt had a problem since. good luck

 

Yeah, I checked all my suspension and steering linkage mounting holes for any type of wear: only one I found was the axle-side track bar mounting bolt, which I diagnosed by cycling the steering back and froth and the bolt moved even when torqued to spec. You can see that in my build thread. All the other mouting holes seemed true and didn't display any play when the suspension or steering were cycled.


What you see here are two Grade 8 washers welded to the stock track bar mount on the axle. The fully-welded washer on the right is matched with another on the other side of the mount. The partially welded washer on the left simply acts as a spacer for the Superlift steering stabilizer relocation bracket that mounts to this location.

 

Your shop is incompetent.

It makes no sense to install cam bolts with adjustable arms.

They did not properly torque the track bar bolts during the install--which led to the problems in the first place.

The DW from the loose track bar bolts likely was the cause of the damage of the knuckle side drag link end--which needs to be replaced if it is loose enough that it clunks during a dry steering test and/or moves up and down when tested with channel lock pliers.


Remove the cam bolts (requires welding washers or plates over the holes they knocked out) and adjust the arms to somewhere between 4 and 4.5 degrees caster.

Replace the worn drag link end.

Thoroughly inspect everything else in my written checklist.

Retorque your suspension bolts at every oil change interval.


It is fixable. Just don't drive it until you at least replace the drag link end.

 

x2 what planman said. just checked out your build thread.
hope it gets figured out soon.

 

Having the tires balanced is pretty cheap and if your getting vibes only at one speed it seems to point to that. The dual SS is money down the drain, if you get your suspension right you won't need an SS at all. Use that money to pay for your balancing and actually fix something instead of covering it up. And I'd stop taking my jeep to that shop if I were you, adding cam bolts to a setup that already has adjustable control arms makes no sense. Was the dual SS their idea too?

Also I've got a taller lift but a drag link flip did wonders for my death wobble issues. I just got new axles and am selling my old flip kit if you're interested.