Death Wobble - Possible Resolution - Page 6

jydog · 04-12-2015, 03:46 PM

Just to add my experience to the discussion. I have Dereks CCV 4x4 components on my rig as a diy and had one bout with DW. It was when I first put it on the road with stock 05 rims and 265/70/17 tires and no steering damper. Makes you second guess real quick about safety in a lifted van, after researching this as an inherent problem with f250's and f350's I went with the most common denominator in eliminating DW. Dual stabilizers. Not the cure for what is wrong but the safest way to eliminate it quickly. I remembered reading turbostew's post and I was using bilstein shocks anyway and went that route with my current fix and have not had it happen in 2k miles so far driving back and forth across Atlanta. Caster is 4.25 but I will be changing it to 6 to help the high speed handling . Toe is 0. I did change the rims and tires also to Mickey Thompson Classic II's which I think have a different offset than stock .

With stabilizers with the old wheels and tires

sidetrak06 · 04-12-2015, 07:54 PM

I know that the radius arms are a purchased part for Boulder Offroad, but I will have to ask who makes it. I would guess the poly bushings come with the arms but I will check that. The radius arm/frame bracket has a ford sticker on it so I think it is a standard part that may have been modified or just welded in addition to being bolted. Don sent me an email on Friday in regards to the videos and suggested that I check the arm bolts to see if they are loose and causing that kind of movement. I will get under it tomorrow and see if I can wrench on those a bit.

As for the tracking bar, refer to the previous posts. Mine is not stock and is nearly parallel to the drag link to minimize bump steer. The ball joints were brand new when the conversion was done a few years ago and there is no reason they should need to be replaced yet. REF, Can you point out in what video/time you see the track bar oscillating? As far as I can see the track bar doesn't budge. As pointed out earlier, there is definitely movement in the poly bushings on the radius arm (seen in video #9).

I am fairly confident that if I can eliminate the play in the radius arm bushings I will be able to eliminate the DW. Either way, that movement is not good and needs to go no matter what. I will also check the geometry of the arms and see how parallel everything is. I am trying to avoid having dual steering stabilizers on there since it is just another thing to smash when I am wheeling. However, if I get everything else tuned in and still have issues with DW, then that is the route I will go. Luckily that is a pretty simple thing to tackle, I am just running out of room down there with my hydro assist, haha.

Thanks for everyone's input and feedback, this has been a fun thread. Stay tuned...

sidetrak06 · 04-12-2015, 08:12 PM

BajaSportsmobile, I just checked out the Agile Offroad website and looked at the Dana 50 Twin-Traction Beam system. That is pretty interesting. The pivot point on the drag link seems like it would cause the toe to change as the suspension travels? Either way I bet it is a smooth ride on a rough dirt road. How does that axle setup handle rock crawling and super-flexy terrain? I am sure it isn't quite as capable as a solid axle but a much smoother ride.

Can someone that has a dual steering stabilizer setup show some close-ups of their mounting points? I am curious to see what variations ppl have used.

E350 · 04-12-2015, 09:39 PM

sidetrak06: Take a look through here:

viewtopic.php?f=24&t=4399&hilit=quadvan+death+wobb le

I won't be able to provide pictures of my set up until at least Wednesday.

Please keep this thread going until you resolve the issue. It has proven to be enlightening at least to me and likely to others as well.

sidetrak06 · 04-12-2015, 09:47 PM

Thank you. I am still debating whether that would do anything for me since I have the hydraulic assist. I can find no one on the internet that is running hydro assist with steering stabilizers that have data for needing the stabilizers. Just guys that had the stabilizers, added the hydro assist and never removed them. I guess it is something you can't know unless you try it. If someone can find an example of this setup being used please share.

REF · 04-13-2015, 04:59 AM

No, your right, track bar does not seem to budge. Just to eliminate any confusion, I looked back at my post, I had said it looks like your drag link and radius arms are oscillating. My point was that most sources, including quigley, blame the track bar and worn ball joints as the culprit of DW. Here's one more outfit making a replacement track bar for a cure......what happened to the emojis? Some of he best ones went away....insert here-beating a dead cow-
http://www.wcmotorsport.com
Good luck with finding the culprit, would be great if it were as simple as tightening a few bolts....

BajaSportsmobile · 04-13-2015, 08:24 AM

Quote:

Originally Posted by sidetrak06

Don sent me an email on Friday in regards to the videos and suggested that I check the arm bolts to see if they are loose and causing that kind of movement. I will get under it tomorrow and see if I can wrench on those a bit.

I am fairly confident that if I can eliminate the play in the radius arm bushings I will be able to eliminate the DW. Either way, that movement is not good and needs to go no matter what. I will also check the geometry of the arms and see how parallel everything is. I am trying to avoid having dual steering stabilizers on there since it is just another thing to smash when I am wheeling. However, if I get everything else tuned in and still have issues with DW, then that is the route I will go. Luckily that is a pretty simple thing to tackle, I am just running out of room down there with my hydro assist, haha.

Thanks for everyone's input and feedback, this has been a fun thread. Stay tuned...

First thing to do is see if anything is loose at the radius arm pivots and where they are attached to the axle.

One test that I would do is get two heavy duty ratchet straps and strap to the axle, pulling it rearward to put load on the radius arm bushings. I would look to see how much deflection I got statically and then I would run the same test drive (with camera) and see if it helps by tightening up the movement in the radius arm assembly.

Use caution with the ratchet straps and loose ends.

BajaSportsmobile · 04-13-2015, 08:30 AM

Quote:

Originally Posted by sidetrak06

BajaSportsmobile, I just checked out the Agile Offroad website and looked at the Dana 50 Twin-Traction Beam system. That is pretty interesting. The pivot point on the drag link seems like it would cause the toe to change as the suspension travels? Either way I bet it is a smooth ride on a rough dirt road. How does that axle setup handle rock crawling and super-flexy terrain? I am sure it isn't quite as capable as a solid axle but a much smoother ride.

There is some toe change, but we minimize it and it is not a problem as it is at the extreme end of the down travel.

It is more capable than a solid axle in the same vehicle, everything else being equal. The independent wheel movement is a distinct advantage. In sand, it is way better than a solid axle.

sidetrak06 · 04-13-2015, 09:01 AM

Quote:

Originally Posted by BajaSportsmobile

One test that I would do is get two heavy duty ratchet straps and strap to the axle, pulling it rearward to put load on the radius arm bushings. I would look to see how much deflection I got statically and then I would run the same test drive (with camera) and see if it helps by tightening up the movement in the radius arm assembly.

Use caution with the ratchet straps and loose ends.

This sounds terrifying, I think I will pass on the dynamic test, but I could try the static test if I get some nice ratchet straps.

sidetrak06 · 04-13-2015, 09:59 AM

Well I just got under the van and tried to wrench on the radius arm bolts and everything was tight. I could see some cracking going on at the front bushings but it was hard to tell if the same is happening just looking at the rear.

I also checked the geometry of the radius arms and they are NOT parallel. Center-center in the rear measured about 39.5" while up near the axle it was closer to 35.25", which means they narrow up by about 4.25".

I am not sure if/how this has an effect on my DW but it is something I never realized before. Can anyone chime in on this? I would imagine that the urethane bushings allow for the misalignment. I can't see how this alone would cause the axle to move forwards/backwards vs a perfectly parallel setup.