Advanced Death Wobble

[36Fan]

Thats low on the caster numbers, I run between 5-7 on my stuff. I wouldn't rule out the tires either.

 

[pcf_mark]

I did this alignment check at home using a digital level so it could be off a bit. I have 5 degree bushings on a stock suspension truck.

 

[pcf_mark]

I also wanted to mention I checked the wheel run out and it was +/1.015 or .030 total run out with the lug nuts tight. I was astonished - my forged factory wheels are the same on a car 50 years newer. I thought maybe the wheels had run out and it was causing a wobble. I rotated the tires side to side but no road test yet I lost a power steering hose.

 

[pcf_mark]

I swapped my tires side to side on the front and took it for a drive on the same route I usually have predictable death wobble. I can say it's behavior is different but not gone. It is not pronounced or frequent. I used to be able to feel it starting before it got really serious but now it just seems to happen w/ little warning.

This makes me think one or both of the tires is the root. It was said that the truck has to "want to do it" and then be able to "do it". Anything I can do to prevent it from starting if everything is tight?

I'll try to swap to the rear tires once I have the means to hog out the wheel openings.

 

[.94 OR]

What's your air pressure set at? Front and Rear.

 

[Tiko433]

This was a hell of a read , great information and as usual good sense of humor. Not sure if it was mentioned but along with those track bar bushings , check the bolt itself.

 

[DirtDonk]

And in the case of Broncos, both bolts!
The upper bolt gets rusty and worn out and, aside from wobbling out the hole, the bolt shank itself gets pretty worn down.
And even though the lower bolt is tack welded in place, and only rarely the subject of rust-down, the tack weld can break loose and make the bolt wobbly even when fully torqued.
Neither of those will cause a Death Wobble, but they will definitely cause wandering and a loose feel to the steering.

Literally thousands of Broncos have experienced loose and/or worn, track bar bushings, sleeves, bolts, and mounts, without ever experiencing a Death Wobble.

 

[eBronc2]

Drum or disk brakes? Either way, if the drums are out of round, or the rotors are warped, rolling down the road can set up a vibration that will escalate into death wobble.

My '97 Jeep XJ was notorious for dragging/sticking front calipers that would not always fully release, causing the pads to drag on the rotors and overheat them, causing them to warp. I'd be cruising down the road, feel the wobble coming on, and suddenly it was like The Hand Of An Angry God had grabbed the front axle and was yanking it side to side as fast and as hard as he possibly could. I'd get it slowed down, pulled off the road, and have drivers behind me stop to check on me because they had seen it shaking so bad.

Fun.

I did all the usual fixes - new steering damper, new track rod bushings, checked the alignment, rotated the tires, etc - when I finally replaced the front rotors, calipers, pads, and flex hoses, problem went away.

 

[DirtDonk]

Good info. Thanks
Interesting aspect.