Death Wobble?

[BELMONT148]

I was just sitting here with my tire shaking still on my mind from the other day trying to figure out the order of steps to start eliminating it. Now that I reflect, I can't think of any reason why I would have disengaged the front drive-shaft before pulling out on the hwy or I definitely would have not disengaged the hubs. Could this be the start of all the problems seeing as I am locked, with a less than perfect pinion angle on the front.

Just brainstorming at work. The list right now is:

Retorque every bolt on the front-end, lower air pressure to 7.5 psi, adjust toe-in, and add 8 oz. of RV (drinkable) anti-freeze to each tire. I guess I need to add disengage all 4wd to the top of the list first.

Jeremy

 

[BELMONT148]

Well, not a 4wd issue as the hubs were unlocked.

Now to test after the rain stops tomorrow after tightening everything down, then trying with lower pressure, then try the fluid, and lastly swap tires front to back one at a time in case a rim is worse than others.


To be continued...
Jeremy

 

[Trollhole]

What is your castor set at?

 

[BELMONT148]

It's what ever Proffitts Cruisers set them up at. I bought the axle already C/T by them. I did move the axle a little further torwards the front than stock, and used stock shackles thru the frame so it could have moved the caster a little from where PC set it up at. However, I doubt it made that much of a difference. I can check it again, but I believe I put the level on it before and it was within range for a SOA rig.

Now toe-in may be something I need to check again. I did it in the garage, and while I might have gotten close enough for the skinnier Swampers on stock wheels, it may not be enough toe-in for these wider, heavier tires.

Jeremy

 

[BELMONT148]

Checked caster, it looks to be at 5*.

Jeremy

 

[99UZJay]

Um, i'm no expert but I thought FJ40's should have like 0* to -something* of caster... That was what I thought... Mine with Caster Correction shims sits at like 0* to -1* and is smooth. I'll let Marshall weigh in on this as he is the expert on these

 

[Trollhole]

Um, i'm no expert but I thought FJ40's should have like 0* to -something* of caster... That was what I thought... Mine with Caster Correction shims sits at like 0* to -1* and is smooth. I'll let Marshall weigh in on this as he is the expert on these

5 is about right with big tires.

Mine is at 6.

 

[BELMONT148]

Stock is 1*, you want it to lay further back so the vehicles tracks straight down the rode because it is lifted higher with bigger tires. Think of a drag car it has crazy caster so it stays straight down the track. Anything under 10* is not considered extreme, it just helps tremendously. Most shops like ACC setup the SOA fronts between 4*-6*.

Jeremy

 

[BELMONT148]

Now that the truck has thawed out, I believe I have found the culprit. 2" of toe-in.

Jeremy

 

[dbenke]

WOW!!!! that's a lot
Should have the tires squalling going down the road.

 

[BELMONT148]

If it was I couldn't hear it from the V8.

Jeremy

 

[BELMONT148]

I adjusted the toe-in to 1/8-1/4 saturday but just tonight got a chance to test her out. She is MUCH better now. I was able to get the V8 to 4th gear for the first time. I drove around the development for about 15 minutes first under 35 to get the tires armed up and I did still notice a DW at 35+. Nothing that wasn't manageable though. After the tires warmed up it pretty much went away. If it did start to shimmy the wheel the slightest little bit, I would hit the gas and it would level out. I am running the tires at 10 psi, and I think I am going to try a little more air just to be sure before I add any fluid the tires. It is fine the way it is, I just wouldn't trust anyone else to drive it as you have to know how to power through the shake.

She did ride smooth and I got her up to 45. I drove her a mile from the house, first step before I start driving her around town.

The redneck ram hydro assist steering I just got should take out any shake that is left. Just got to find time to weld up a mounting bracket for the ram.

Jeremy