Hello all,
I have a 2000 7.3 F-250 with 4x4 and ESOF hubs (the vacuum lines are disconnected) and I've been having a problem with my steering, particularly when changing the direction of my steering (e.g. going left, then turning the other way) that is most noticable making small adjustments going straight.

I believe I have it narrowed down to the front axle shaft U-joints. It's important to note I haven't had the 4x4 working for a couple years now, I never needed it and never replaced the shift motor, so the front 4x4 hasn't been used for multiple years which could be contributing to the problem

Basically, it's as if the U joints get stuck when the wheels turn, but steering more releases them, so driving on the road I end up oversteering and have trouble staying straight.

Below I have a video turning the wheels with the engine off and the axle on jackstands.

https://youtube.com/shorts/Tf9bdDHyuOU?si=F8pNuBrMr7km9zbG

I can't tell if it's the U joint itself, or the hub. The ball joints seem to be fine and I grease them regularly. The U joint is non greasable and likely factory. Truck has around 500k miles.

Locking the hubs fixes the problem.

I would like to have this resolved in a couple weeks, so I want to know what parts to order and find a guide to tearing down each knuckle when the time comes.

 

Yup, the axle shaft u-joints are a very common cause of those symptoms. You can verify by turning the wheels a bit to one side or the other and rotating the axle shaft on each side with a bat or screwdriver. You should be able to turn them a full turn without much binding.

To change them, you'll need the joints, I'd recommend Spicer SPL 55-3X, the knuckle seals (National 710493), new o-rings for the wheel bearing assemblies (Dana 417812), the axle tube dust seals (National 710413) and you may as well replace the small roller bearings that are in the wheel bearing assembly to support the axle shaft (National B2110), just make sure to manually pack them with grease before installing them.

Oh, and be sure your ball joints are good before putting it all back together since you have to do all of this over to change ball joints.

 

Thanks, I'll get those parts on the way. Is there an online guide to disassembling the knuckles that you know of?

Additionally, I imagine changing the dust seals on the axle tube would spill grease, what kind of grease does the axle tube take? Is it the same as the the roller bearings?

 

1. It's a 2000, you can probably just replace the entire hub bearing assembly (been a while so I'm not 100% on that) and save yourself a LOT of time. This gets you all new bearings and seals for the hub itself, and isn't much more expensive than buying all the individual components.
2. The dust seals in the axle tubes are literally that, dust seals. They keep dust out of the axle tubes. There is NO grease in the axle tube, and there is ANOTHER seal over by the differential that keeps the gear lube inside. Be careful not to dislodge THAT seal when reinstalling your axle shafts or you'll need to replace that as well. There IS a dust seal for the back side of the bearing hub that attaches to the axle stub shaft (the part that goes through the hub, what above called the knuckle seal) that requires a special tool to properly install, or you could damage it.
3. The knuckles themselves come off pretty easily once the axle shaft is out, you're just separating ball joints from the axle. Getting the ball joints out can be a pain if they've never been done, you need a GOOD ball joint removal tool and might need to add some heat. The cheaper ball joint tools will just bend - I had a cheaper tool for cars, but the c-frame of it just spread open and the ball joint on my '99 didn't budge, I ended up taking them to a local shop and paying the guy $100 to R&R ball joints on both sides.

 

If the wheel bearing assemblies need to be replaced, the small roller bearings will be pre installed, if the wheel bearings are OK, the little roller bearings are only 15 or so bucks each and take less than 15 minutes to change. You really don't need a special tool to install the knuckle seals on the stub shaft. You just need to be careful and get it started straight, then tap it down evenly. You can also find a piece of PVC pipe that fits the seal, put an piece of 2 x 4 on it and smack it.

EDIT: Service Manual

Ignore the part about removing the wheel speed sensor from the bearing assembly; that's never gonna happen. Just separate the wiring harness from the clips so you have enough slack to set the bearing assembly on the ground.