I've been trying to figure out why its hard to turn my wheel to the right and not the left while avoiding changing the steering gear box because I really don't want to dive into that and I dont think thats where it is. I say this because it is not a constant pressure but more of a build up of binding until you have force the wheel past a point which is when you hear a "clunk" of various volumes coming from the front passenger wheel area. Almost feels like there is a U joint knuckling. I'll tell you what I've done so far, tried pretty much all the typical offenders with no success: FYI 94 F250 D50 IFS - that may be a given but just in case

Checked all the ball joints/steering joints, made sure they were greased up, torqued the wheels up and down. everything good to go.

checked the tie rods/ends, torqued the wheels side to side, no excessive play there either.

Swapped out the axle u joint on that side. It needed to be replaced, but it was also not the problem because the new one didnt change much.

Took both hub/spindle assemblies off and compared them side by side. The only thing different/missing was the needle bearing/axle oil seal (pic below) on the passenger side. The one on the right is the passenger side, notice the rust colored ring where it no longer is and the absensce of ring on the left side where there is still a black plastic seal. I figured I had made my own little Einstien discovery. Well....no that was not it either.



I'm hung up on this passenger side outer axle area because when you take the cap off of the hub, the outer axle shaft is not centered in the hub gears



when you turn the wheel, the knuckling feeling occurs as the axle shaft and hub gears seem to move opposite relative to each other. the thunk happens and the shaft jumps to the other side of the hub, but it always stays in the top half, putting pressure on the top side of the internals. if you wiggle the shaft from the end it always springs back to the same orientation up top. All of the bearings and races look good. By that I really mean they dont look obliterated and the fit and function of both feel identical.

What do you think? My last guess is that maybe the camber is off too much in the positive direction? I can't tell from looking at it if its cocked to the side or if its just the road surface. Is this possible? I'm going to try adjusting it tonight or tomorrow per the directions in the shop manual. If it doesn't work, I might try switching from the Motorcraft Method to the Remington Method of the shotgun approach because I'm all out of logic based ideas

 

i am pretty sure there is a bushing in there(well supposed to be) that holds the axle in place.

 

How does the spindle look? Could it be bent..? Is the axle shaft bent? Are both bent?

Something isn't right if the axle shaft isn't in the center of the hub. What piece is engaging the splines on the shaft? that part can't be working right if the shaft is off center right? Is the axle shaft sitting at the right spot? I haven't pulled apart a D50, just my D60, but is the axle shaft sticking out far enough? I believe there is a circlip that holds the end of the shaft in place, but maybe I'm thinking of something totally different.

If you haven't already, put the axle up on jack stands, and move the wheel back and forth when there isn't weight acting on the wheels/hubs. See if it still acts the same.

 

It doesn't look like either shaft or spindle is bent. Since I've bought it I haven't used 4x4 and this problem has developed months after I bought it. It almost seems like the u joint is sagging. Almost as if when I push down on the splines on the end of the axle then let go, the weight of the u joint is not being supported by something so it falls, therefore putting the end of the shaft up

 

There is supposed to be a needle bearing in the spindle, as shown in this diagram:

This is often neglected since you need to pull the spindle to get to it and it's pretty exposed even with the seal. The bearings are under $20 each, you can get them from most auto parts stores.
This should fix a good portion of the problem. The outer end of the outer shaft is kinda supported by the lockout mechanism, but the needle bearing really needs to be there to keep it all aligned.

 

I should mention that I have been driving around in 2wd with the hubs locked in, which keeps the axle shaft as close to centered as possible with all the gears being interlocked. I know this isnt great for the truck or idea for mpgs but it helps with the steering issue. When I had the spindle off I saw that needle bearing you're talking about. I put my finger in there and ran it around the bearing and it seemed to function fine and didnt seem to have any slop related to how it sits in there. I'm assuming to replace the I'm going to need a bearing puller or some similar sort of improvised device because it felt like it was pretty snug in there, but I didnt want to pull too hard in the wrong direction. The castle nut on the top ball joint on the problem side wasnt "loose", but it did have a little wiggle room so I took the pin out, tightened it a notch and now its snug, but still the joint itself has no play in it. Beneath the castle nut there is a toothed, angled or beveled washer, is this some sort of shimming/adjustment washer? I couldnt separate it from the knuckle so I just let it alone to save myself any unneccessary headache from ensuing

 

That "washer" you mentioned is the camber bushing. It is a tapered bushing, with an offset tapered hole. It fits into the steering knuckle, and the upper ball joint fits into it. They are available with different offsets. Camber & caster are adjusted by putting different offset bushings in. If the alignment was correct when the ball joints were new, the same bushing should be used.
(If you're going to have it aligned after you get it back together, you should knock out that bushing, and re-install it now. That will make it a lot easier for the alignment tech...)
With that needle bearing, you could clean things up and put the outer axle through it and see how much play there is. Compare it to the other side. With the passenger side seal gone, I imagine that the bearing is probably toast.
National (made by Moog) part# SBK-5 has the bearing, spindle seal, and the axle seal...