What exactly is death wobble - diagnosis please

[Cortez]

Ok here's the skinny. I bought my '67 a year ago and have been working on her off and on. Finally got her tagged and "roadworthy". She drives great, but on the highway I occasionally get this freaky floating sensation with the body twisting side to side (is this the famous death wobble?)...but only when I hit a certain type of bump...it has to be a rolling drop or something that makes the whole truck rise and drop...not a pothole. Appears to be worse on the passenger side.

Tracking is dead-nuts straight.

Brand new tires - balanced

new 3.5" lift

drop track bar bracket - I will check on the bushings but think I replaced them

Swapped in D44 front end and am suspecting the c-bushings - these I know I did not replace as they appeared in good condition, but since I didn't buy them myself I can't vouch for the degree of offset - I was told they were for 3.5" lift.

What should I be looking for?

Could it be a shock? - seems to take solid bumps and potholes fine.

Should I put in drop radius brackets?

Thanks for any help.

 

[70_Steve]

Not Death Wobble. Here's a video of Death Wobble
http://www.emotoman.com/videos/dw.mpg

 

[4lofun]

wow, that video looks just like a heep i saw on the highway. thought he was so cool passing me then as i exited , looked over to see his death wobble heep...!!! he stopped and i kept on going.. so what causes this is the question??? drag link,trac bar issue???

cortez, sounds like your shocks are not slowing the spring bounce. are the shocks new?

 

[Broncobowsher]

It almost sounds more like you have some bumpsteer issues.

the last floating side to side front feel issue I had was when the track bar angle was too steep. It drove straight but in dips the arc of the track bar would cause the front to shift sideways as the springs cycled. But you have a drop bracket, that should corect that.

When I fixed my track bar I found the body shift went away but the steering needed turning in order to go straight over the same dips in the road. Heim joint steering (instead of a drop pitman arm for me) fixed that. then life with a lifted Bronco was happy (except for a few times when trying to drive 100 MPH or on the throttle heavy going through a traffic light...)

 

[Bronchole]

That video is a perfect explanation of death wobble!

Basically, if you have to ask, you don't got it

I think Broncobowsher is on the right track.

 

[LilRedBronco]

I think mine is caused by a loose trac bar. First time it happened to me the wife and I were driving by a church and I made a comment about something because I have a bad sense of humor and bad timing anything as soon as my comment exited my mouth my truck started flippin out and scared the living SH4T out of us. It literally felt like god had placed his forefinger on my roof and was pushing the truck around.

My wife looked at me and said that is what you get for trying to be Mr Funny

 

[Ned]

Death wobble sux! What your discribing is not that, judging by the discription sound like something is loose or cracked with or around your tracing bar. If the angle was too steep you would be getting a little bit of the wobble but what you are discribing is like when you unload the suspension as if you were jumping it the axels are shifting. Unless you have a 4 link in the rear your leafs should center that pretty well. As for the front have you put the it up on jack stands or a lift and looked to see where everthing is going when totaly unoaded, ie airborn?

 

[Cortez]

front end

Thanks for the comments guys. I'm going to dig into the possibility of the shock's causing some of this. The shocks aren't new...they came with the D44 swap and, while they seemed ok...perhaps they aren't keeping it steady up front. The steering stabilizer helped a good bit...to the extent that I thought a second one would be even mo betta'

Let me know if there's other ideas.

 

[Cortez]

wobble

Somewhere between the trac bar and shocks must be the issue it is like when the suspension is unloaded this happens. I seem to get about 3 bounces when it happens on the highway that's why I though shock issue...but never in my 40 years have I had a car with a bad shock that allowed bouncing. I'll get into it this weekend.

 

[bluemonday]

When I bought mine the PO told me about the wobble. I talked to the guy he bought it from, that is when I found out about the trac bar bushing. Had to put a torch to the nut, impact would not budge. Bought bushing a local auto part store. It cured my problem. The PO drove it to my house. It was so funny to see the wobble at about 20 mph. Every piece of dry dirt from underneath fell to the road.

 

[302fix]

...floating sensation with the body twisting side to side...

How do your body mounts look?

 

[ken75ranger]

Zero caster can give you that floating feeling too.

 

[Cortez]

body

body mounts are new.

 

[Cortez]

caster

Ken,

I keep getting caster and camber mixed. Define caster for me...is that what the C-bushings set?

 

[Broncobowsher]

C-bushing is for Caster

When you lift a straight axle you are getting into a Caster Disaster

 

[Bronchole]

Camber is how far your tires lean in at the top when you have jumped the Bronco a little bit too high.