Help diagnose death wobble!!

This is my buddys land cruiser, he's been chasing this steering issue for a while. Heres what we've eliminated: tie rods, rod ends, steering box, alignment. All of it gone through and checked. You can see in the video that it seems to be harmonic. As he accelerates quickly about 3 minutes in it misses the death wobble, but as he decelerates back through those speeds it picks it up again. Really strange and we just can't seem to track this thing.

https://docs.google.com/file/d/0B-gAzVqVtSrcNHRlMzRHT1pxLWM/edit?

 

u joints? Does he have a lift and small tires? Is the steering stabliser in good shape?

 

Those are 44" tires , big lift

 

Sorry I should have told ya the link didn't work for me but I'm pretty sure you can't balance 44" but don't qoute me on it maybe that is the issue, thats all i can think of at the moment.

 

I have the same thing going on with my truck. I'm going with a hydro assist set up to see if that will fix it...if I ever get time to install the damn thing.

 

Hydro is the way to go with that size of tire i totaly agree.

 

You can, and at any rate this would have to be SEVERELY off balance to try and kill you like this haha. He said the video should be open to viewing if you have the link

 

Well you learn something new everyday haha but maybe there is water in the tire my buddies heep has water in it he said it help on the rocks but god the damn thing nearly killed us.

 

It looks to have one on the tie rod and one on the drag link.

 

Damn I just saw the video thats terrible .

 

tire balance? are the tires missing lugs/thread?
warped/bent wheel?

 

whatever it is. i wouldnt drive it, looks pretty bad. lol

 

HOLY SHIT that was pretty bad haha. I know death wobble happens more with home built set ups, but that's built from the factory with the axle...too much play in the aftermarket components?

oh ya, nvm. just saw the steering arm at the very edge of the vid

maybe beefier stabilizer?

try throwing some stabalizing beads in the tire to eliminate those as the problem?



also can we see more pics of the rig?





edit:

honestly looks like it is all comming from the huge amount of play at the top of the steering arm, and it looks like the steering stabilizer is flopping around on the arm as well...or that might just be how much its flexing from the vibes...

 

Two sets of tires have done the same thing. It isnt the tires or water in them.

 

Time for serious suspension work.

 

http://www.tacomaworld.com/gallery/showphoto.php/photo/287377/cat/500/ppuser/59032

Pic of the rig

 

Damn Ben, good luck figuring that one out. I'm useless here other than knowing that is not good haha.

 

It's time for some beefy steering component and hydro assist or just full hydro.

 

You right!

 

I fought the exact same issue with my Jeep JK Unlimited. Scary as hell and no fun while at highway speeds! Replaced all of the front end suspension and steering components one by one until I had it cured. The biggest problem is, once your vehicle has had the DW a few times it accelerates the front end component wear/tear.

After literally days of research and troubleshooting, the following was the cure I found;

First things first, tell your buddy to replace the upper and lower ball joints. I ended up installing rebuildable heavy-duty ones that were expensive but well worth the $. At the same time, and most importantly, check the upper and lower bolt holes on the mounting bracket for the track bar. I would be willing to bet that the bolts holes are slightly ovaled (is that a word?) from the DW. Either that or there may be enough play between the bracket/bolt/track arm bushing(s) to exaberate the DW. The bracket/bolt/track arm bushing(s) assembly must have a very tight tolerance and the bolts must keep properly torqued. Loose or improperly torqued track bar mounting bolts are typically what starts DW in the first place. He may need to weld some grade 8 washers or machined gussets to the track arm mounts if there is any play or elongation of the bolt holes.

Remember, both of these fixes must be completed at the same time. If he just does one or the other, he will likely still have DW and will start the wear/tear issue all over again. DW is a vicious cycle, but it can be fixed.

Good luck!