Another Death Wobble

[the74bronco]

I’d look for input from others on this but comparing factory geometry to your current setup does make some sense but 37” tires are a lot of leverage to excite badness.

Did rig always have death wobble (or at least when you owned it)? When did it first show up?

One last thing, I seem to recall that you fixed the movement at the top track bar connection (and now have new trackbar). Can you remind us what was done to fix it?

I don’t remember the issue initially, but it’s been under the knife more than on the road. It hasn’t been until the last few years I have been doing more highway driving. Didn’t drive it much with the 33’s as the ending was getting rebuilt. I did the 37’s, suspension, axles, engine, transmission before I got it back on the road.

I bought a new adjustable track bar, new bushing, new bolt for the upper bracket (fits tight with no looseness). I do have a washer on the bolt outside the bracket. I also did TJ track bar riser bracket.

 

[bpr]

More than one set of Tires have cause DW on mine in past. Happened with both 40s and 38s, both bias though. 36 bias were fine and now for several years 35 radial fine. The 38s and 35s both used same rims. The 35s didn't have DW even with worn bushings, ball joints, and tie rod ends. All fixed now.


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[Grey owl]

37 inch tires can create massive centrifugal force even at slow speeds. It sounds like you have adressed the linkage concerns. So i would be looking at the caster angles, toe, and tires. Definitely a strong steering stablizer system would help to support consistent steering geometry. A short wheel base hign lift vehicle could create all sorts of gremlins.

 

[the74bronco]

I’m trying to locate some new rims and tires to give that a go. Planning on double checking my ball joints and preload this weekend. Is my caster at 6.8 degrees an okay number? If adding a stabilizer fixes the issue, does that confirm it’s most likely a tire problem? Does anyone have a Bronco on 37’s that drives well with stock axles and steering setup?

 

[.94 OR]

Any reason to believe a steering stabilizer is nothing more than a band-aid?

 

[the74bronco]

Any reason to believe a steering stabilizer is nothing more than a band-aid?

I have always taken this approach. Get it driving perfect, then add a stabilizer, but I have a lot of people telling me 37’s are large and heavy and might require it. I am debating ordering 35’s, but I spent a lot of time and parts to prepare for 37’s, so if I can get it driving smooth with them, I would prefer that.

 

[Broncobowsher]

I have always taken this approach. Get it driving perfect, then add a stabilizer, but I have a lot of people telling me 37’s are large and heavy and might require it. I am debating ordering 35’s, but I spent a lot of time and parts to prepare for 37’s, so if I can get it driving smooth with them, I would prefer that.

Pretty much the same here. It should drive (on the road) just fine without one. I remember reading stories of the early Baja racers bearings to death in the steering boxes without one. I had one break a frame bracket once. On the street I never noticed it no longer worked. Running some off-road trails I noticed every once in a while the steering wheel would suddenly spin violently where it normally wouldn't. Clip a rock/root with a tire things. During an inspection I noticed the broken bracket. Welded it back up, the steering wheel snap was once again gone. So yes, it does work. I run one to protect those expensive power steering boxes from taking a pounding.

As for the death wobble, it did exactly nothing. Every couple years the track bar bushings would wear enough to get death wobble. Stabilizer didn't slow it down one bit. I didn't get a steering wheel shake during the death wobble. The axle itself was occolating side to side while the steering linkage stayed stable. That laterial axle shake may have a little feedback into the steering. But the steering was not the excitation point.

 

[the74bronco]

Has anyone strapped a go pro to the front during death wobble? Would that show anything productive?

 

[DirtDonk]

Lots of videos of that exact thing when it happens on Jeeps and Dodge trucks. Do a quick Google search for YouTube and it’ll probably come up with a lot of examples.

 

[DirtDonk]

Or, watch for the section of the movie “it’s a mad mad, mad, mad world“ where Terry Thomas’ character’s jeep wagon has what can only be described as Death Wobble.

 

[Grey owl]

Any reason to believe a steering stabilizer is nothing more than a band-aid?

I personally believe a proper stablizer can play a huge roll. Vintage Broncos were never designed to be lifted 5 inches with 37 inch tires. Its going to take a lot to keep everything in perfect alignment. Body roll alone could trigger the wabble. There is so many possible causes adding a stablizer cant hurt.

 

[the74bronco]

Lots of videos of that exact thing when it happens on Jeeps and Dodge trucks. Do a quick Google search for YouTube and it’ll probably come up with a lot of examples.

I checked tightness and play on everything today. I rotated the tires again, this time I found the two tires with the least amount of balancing weight and put those on the front. I strapped a go pro on the bottom and watched the suspension. Of course I can’t replicate the wobble.

After all this, I am fairly certain you are correct and it is “always the tires”. I suspect either I have either have slightly bent steel wheel or tires that need replaced. I’ll continue to drive it this week. If I can’t get it to wobble. I will order wheel and tires, throw a stabilizer on and call it a win. I really appreciate your insight!

 

[Oldtimer]

What is the date code on the tires?

 

[DirtDonk]

That’s always a good thing to know. However, even brand new tires can do it.
Two of the Broncos I’ve experienced it with were both sporting relatively new tires, but both were driven over the same curb, pulling up too short, turning in the driveway of the local Taco Bell.
Must be a wicked ass curb to wreck two tires the same way!
This was Death Wobble caused by an internal defect/damage, rather than tread wear, or simple old age.

 

[the74bronco]

What is the date code on the tires?

View attachment 959962

3523 is the date code

 

[the74bronco]

That’s always a good thing to know. However, even brand new tires can do it.
Two of the Broncos I’ve experienced it with were both sporting relatively new tires, but both were driven over the same curb, pulling up too short, turning in the driveway of the local Taco Bell.
Must be a wicked ass curb to wreck two tires the same way!
This was Death Wobble caused by an internal defect/damage, rather than tread wear, or simple old age.

This makes sense. I have but another 30 miles on with no signs of death wobble. Since I have had two different sets of tires with these wheels and both had issues, I am thinking two of these cheap steel wheels might not be straight.

 

[ksagis]

This makes sense. I have but another 30 miles on with no signs of death wobble. Since I have had two different sets of tires with these wheels and both had issues, I am thinking two of these cheap steel wheels might not be straight.

Fingers crossed its sorted out. Go find some bumps and try to excite the DW