So in my hunt to determine why my front end is wobbling I took the passenger side front rotor off - I had to get the old non-functional ABS sensor out of there anyways and the only way that did that was taking a hammer to it from the rotor side - no amount of prying from the back was going to make it come out.

I was successful and also removed what was left of the dust shield - not much.

This is what I am left with :


Spindle - not ethe scoring and the bluing at the tip

Knuckle

Note that the spindle is indubitably scored and the tip looks like it got REALLY hot in the past. The bearings look very, very recent, so does the grease on them.

If I had to guess, quite recently the bearings started spinning on the spindle and were left to do so until the axle got Really Significantly Hot.

They were then replaced - by someone whose use of a hammer on the dustcap is best left undescribed, by the by.

Given that there is NO endplay and NO noise and the bearings look intact, do I just put everything back together with new grease and move along? Is the spindle good enough? It doesn't catch with a fingernail. I'm sort of running out of ideas for the wobble, though.

 

If it doesn't catch a nail and the bearings fit properly I would run it. Make sure everything is greased and torqued to spec. I'd probably keep an eye on it for a while, maybe jack it up every so often and check for play.

 

I'm assuming you already determined the wheel or tire wasn't the problem? Any unusual tire wear on that position? It will show up on the outside shoulder on a twin I-beam since those front ends normally wear that side harder, but cupping or feathering would be a clue. Check the ball joints too.

 

What's the state of your shocks? I've seen them cause front end shimmy if they're shot. The suspension can develop a harmonics from the road and without a decent shock to dampen the vibrations it will get strong enough to be felt in the wheel.

 

To my eye the wear looks very superficial. The fingernail test is a good way to judge extent of damage.

An option if the fingernail grabs is some crocus cloth and wear it around the shaft with the grip of your hand, carefully avoiding the inner part of the shaft. Goal is to smooth out those wear marks with minimal loss of material. Bearings typically have more tolerance for total ID/OD than roughness.

 

Seriously though, use some retaining compound if you are worried about bearings spinning.

 

Thank you everyone, I will recap:
1) Wheels and tires are crappy and incorrect - the PO put 225/70-16 on the OE rims. I have acquired a set of 'Alcoa' OE rims with 265/75-16, factory optional fitment, which will now get installed. I hadn't installed them previously because, well, I didn't want to damage the tires: @Brandonpdx is correct, there is a small amount of overheating damage on the outside shoulder, in particular on the driverside - which was in much worse state than the passenger side, more on this later.
2) The shocks are done. As in, very, very done. I was going to buy Bilsteins, then I saw the KYB on sale and apparently everyone on the forum rates them highly. At half the price and given the amount of use the truck is seeing, I'll give them a go unless someone really discourages me. I was expecting to find wobbling ball joints and tie rods, as mentioned in the other post, instead they are all in very good state: the boots are all intact, they are overpacked with old grease (which I cleaned and replaced with Lucas red through the grease nipples, just in case) and there is no play whatsoever in any of them, I can grab the knuckle firmly and shake the whole truck yet feel no measurable give.
3) Good call on the retaining compound. That will necessitate some delicate handling of the packed bearings but I'm sure I can get creative somehow - and I think I'll try 641 (medium strength) so as to not have to fight my way through the next time around.
4) As I mentioned, the driverside was significantly worse than the passenger side: the nut was loose (!!!) and the small amount of movement I detected when I was yanking on the wheel (again, see previous post) almost certainly came from that: the knuckle itself displays no movement even with a 30" bar, which I judge to be a good metric. Now, the interesting part was the the nut had been loosened ON PURPOSE, the crown cap and the cotter pin were put back on. I couldn't figure out why until I tightened the nut with my fingers and the slight bearing noise I had detected became a growl. The PO 'fixed' the bearing noise by reducing the preload.

Not trusting the past history, I will replace the bearings and seals on both sides, just in case, as well as the dust caps (necessarily - what is left will not serve) and hope that that, plus shocks, will tame the front end enough together with the new wheel and tire combo. I'll keep the tie rods and ball joints for sometime down the road, though the way we've been using the truck that will be sometime in the 2040s... we have to run some errands next weekend and I'll report back on the results. After, that is, taking an air hammer to the inner bearing races, because 'popping it right out' with a punch and hammer has proven to be wishful thinking, there isn't enough lip there.

 

Sounds like a plan, and "I love it when a plan comes together." Can't go wrong with the KYB's in my opinion, been very happy w/ my set.

 

The dust caps are basically one time use. I've never figured out how to get one off without mangling it. Sure, as long as you're in there put the KYB shocks on and go with new bearings and cups. (Stick with Timken if possible but SKF is probably fine too). I would go with a high quality synthetic grease such as Amsoil "General Purpose" (the red stuff)...no moly greases for wheel bearings. Install new wheels/tires and drive it straight to the alignment shop.

 

I don't know if those are the same hub/rotor assemblies that the 2wd DRW's use, but on those the minimum rotor thickness is 36mm before they need scrapped according to the shop manual. IMO it isn't a great idea to use super aggressive brake pads on those unless you want to be replacing them every damn time. A nice long life/rotor friendly pad is a better idea to keep the cost of maintenance down.

 

An update, after actually finishing the bearing replacement and taking a brief (20 mile) test drive.

Rotors and pads are new. New as in they were changed in fall of 2018, about 2000 miles ago. It shows - the rotors have no wear on them and the pads look like they just came out of the box, with the corner bevels still well visibile. IIRC the rotors are the same as the DRWs but these latter get the 'hub extension' contraptions to be able to use DRW style rims.

Noted on Timken bearings - I used SKF which are a known quantity to me, but will keep in mind for next time. I also used the Lucas red grease but will research the Amsoil GP (which I suspect is similar).

Alignment shop will be a LITTLE interesting, for whatever reason the local Firestone (they're my go-to) said they wouldn't do trucks. The place I usually take my cars is some 70 miles away and there is no need for it on this truck.

The truck drove materially better. It still has a slight vibration between 70 and 75 mph which goes away above and below - I am willing to bet that it's one of the crappy tires. It actually stays on the road and in the lane, pulling slightly to the right on surface roads which to a certain degree I understand is inevitable, given how humped they are. After the alignment I'll get the Alcoas with the BF Goodrich tires on.

Next step, I think, shocks and steering damper (I found the Ford retrofit kit for it). In 500-1000 miles or so I'll take the dustcaps off again and check the preload, I went to moderate tightness with socket in hand which should (?) be more or less where it needs to be.

 

Probably a tire balance issue with the vibration at 70-75.

Books says tighten spindle nut to 21 ft/lbs to seat bearings then back off 120-180 degrees and then re-torque to same while spinning hub. 18 in/lbs should turn hub by the spindle nut or it's too tight. Says simply to jack up wheel position and push/pull on the tire to check for excessive end play.

I got curious and looked up the P/N for the DRW vs SRW twin I-beam front hub/rotor...same P/N except one is an "AB" and one a "BB". I have a DRW but don't think I have a spacer or anything. Maybe somebody else can straighten that one out.

 

Huh, 21 ft/lbs is not .. nothing, a lot more than I'd be capable of pulling holding the socket in my fingers - and I didn't strain at that.

I did do the 'spin, tighten with a ratchet, back out, take socket in hand, tighten until you can't go any further with fingers on socket using your wrist, not your arm, then back out one crown cap tooth or so' - I actually got that from Watch Wes Work - that is a LOT less than 21 ft/lb... but where does the 18 in/lbs come in? Is that supposed to be the amount of resistance from a properly set bearing/rotor assembly? (I assume it is). I will add that I did not have any end play, even with the wheel on, and that the noise from the (new) bearings increases if you tighten any further than I did.. quite quickly.

As the bearings are set now per above procedure there is no noise - to check it I have to remove the calipers because, for whatever reason, these pads are NOISY when they're near the rotors. I do not know what brand they are, but the only other pads that made this amount of noise in a completely different context were ANGRY track pads which would STOP the car in a hurry but were unbearable when cold. Something like that does NOT belong on a truck - or anything that drives on public roads - and the braking on the truck doesn't seem to match with that kind of pad compound.

Let me show you what I mean with spacer, ref the SRW/DRW doubts, from a Makuloko YT video:
I thought both RWD and 4WD DRWs had those... adapter things on the outside of the front rotors?

 

All the more reason to use retaining compound on what sounds like spindles worn down by spinning bearings.

At the risk of insulting your intelligence, are the pads that are making noise flipped such that the backing side is facing the rotor? I have made that mistake myself on other vehicles.

 

If you thread one of the lug nuts back on take an inch/pounds torque wrench set to 18 and try to tighten the lug nut, it should rotate the whole hub without clicking the wrench off is basically what that means. If the wrench does click off it means there is too much pre-load on the bearings. It's a small spindle on the 250/350. Larger on the 450/550. Guys who do a lot of this type of work can usually tell just by spinning the hub and knowing how free it should spin but that's why they give the little test.

The pads will rub a little on the rotor and sound like a pencil dragging across a sheet of paper, but get an IR gun or use your finger to check for excessive heat on all your rotors. Parts store calipers don't seem to last very long on these trucks before they start to drag and not releasing properly. Not as easy to notice with an automatic trans.

I'm pretty sure on mine the hub/rotor is all one solid piece. That's a 4wd front end in the video and yeah I can seen the DRW adapter that bolts to the end. Maybe the 2wd hubs are slightly different between the SRW and DRW to account for the different wheel back spacing. Not sure.