Most common cause of death wobble are the front hub swivel pins out of adjustment or loose steering linkages. Have you looked into that yet? Look on Youtube, there are some good videos outlining swivel pin checks/adjustments/rebuilding.

Steering boxes, (I'm talking 'general' steering boxes here, as I haven't worked on my L/R steering box yet, but have rebuilt others) have a couple preload points (like input shaft) that need to be within certain tolerances besides the output shaft preload which you can do from the top. Bearings and bushings can also be worn which could lead to loose steering. If the lower output bearing /bushing is worn then the output shaft will have just enough play and that play is multiplied through the steering linkage. A lot of classic car guys (that's a crowd I know a lot) think just adjusting the top nut on a saginaw or ford box will resolve steering issues, but the input shaft play (or preload) should theoretically be adjusted first. If that is not tight, then all the adjusting of the output gear won't get rid of all the play (although it may help some). And of course the lower bearing (or bushing) which takes a lot of pressure needs to be assessed first. I've also seen input shaft bearings and their races all corroded because water from off-roading or washing the engine compartment (classic cars) runs down the steering shaft, makes it past the top seal and literally 'sits' in the bearing. On 60's-80's Corvette steering boxes, and others as well, the lower output shaft bushing wears fairly quickly and no adjustment will take that out. Problem is, the proper way to do the adjusting and inspection is to take the steering box out and bench test/adjust things, and that's a lot of work!

Where you are at now, if it were me, I'd get the top pre-load adjustment screw readjusted as good as possible with the top screw. I'm not sure why you can't get it adjusted back to where you had it. It basically pushes down on the output shaft. Then, when you have that, have someone in the vehicle go back/fourth on the steering wheel in a rapid manor only moving like 2" at a time while you watch closely at the output shaft area above the steering arm to see if you can detect any lower bearing play. More than likely you have other steering parts worn worse, but you never know. If it is your steering box, remove and I guess I'd look for a remanufactured unit. I see PartsGeek had one for about $350. It's a lot of work rebuilding one and, considering the parts and yer time, really, for $350, that's a better way to go IMO. I don't think I'd rebuild my own for that kind of money, and going used may not solve anything unless you know it's for sure good. A good used one is probably the least ideal unless funds are super-tight (and when AREN'T they?), or you can get a decent one cheap, but a reman would be ideal if you can swing it. But check your other steering parts first..

Well, hope this helps. Good luck.

 

Thanks Mark. It drove fine before I mistakenly undid that nut and the adjusting screw. I can adjust it back but my problem is I don't know "how much" to adjust it. I mistakenly didn't do a thread count of how many were showing before screwing with it.

I guess that would be a start - is there a norm? 3 threads showing? 4? 10? something to get me at a point where I can drive and see how it feels? I know that's not the best way but it's a start since I am 99% certain that's where my screw up lies. I could keep on giving it a couple turns and then driving but that's a lot of up and down on jack stands (I read that's how it has to be adjusted correctly).

The PO did a ton of work with the truck, new steering box, hoses, drag link, steering damper relocation, etc.

 

You could try ten turns or adjust per manual.
......

 

The manual says:

Which seems like a lot to go through to simply put a screw back to a semi-normal setting and then adjust in or out by feel from there. I'm not trying to fix it blind, per se, I'm just trying to get it back to where it was.

Kind of like tuning a carb. You know the starting point on an idle screw is 1.5 turns out. May not be the right setting, but since you adjust in 1/4 turn increments, starting at 1.5 is a lot easier than starting at 0. So people always say "make sure your idle screw is 1.5 turns out before you start fiddling with it."

That's kind of what I'm asking. Is there a starting setting - 3 threads up top, 10 threads up top, etc that I can put it at and start from and see how it does, rather than do all the above? Maybe there isn't but it can't hurt to ask. Someone might even walk out to their Disco one and look at it and come back and say "Mine's in pretty good shape and looks like about 5 threads showing above the nut"

 

I wouldn't worry about the # of threads. What I would do is tighten the stud down until you feel it get snug. Have someone inside wiggle the steering wheel back/fourth while you put a little more tension on the adjusting stud. I can't remember if it's a screwdriver slot, or a nut, but either way, just get it tight. If you want to do it in steps, back it off a little, then tighten the lock nut. If, after driving it a little, it needs a little more, tighten it a touch more. The ones I've rebuilt, it's hard to really overtighten w/o really cranking hard on the stud.

 

Is there any harm in tightening it more than specified in the RAVE? I've been running months with it adjusted exactly per the rave, but it feels too light for my liking, and when I have a trailer hooked up the front end feels more squirrely than I like.

Today I simply adjusted it in about half a turn. Steering is heavier but still returns to center after a turn on its own. Feels a lot better to me but don't want to screw up anything....then again I figure a steering box is in my future in the next year or so.

 

The preload on the swivels is what determines the feel of the steering, adjusting the steering box only removes the free play in the sector shaft.
Too tight and it will affect the self centering of the steering.