Supposedly you can whack on it with a mallet, work it back and forth and get it off that way. But I haven't ever had that work on one that was actually stuck.
Also I hear people talk about getting a slide hammer with an adapter that threads onto the end of the spindle. People say that works well (personally I've never tried it).
What I've done can be hard to put together if you don't have the resources, but it's easy to use once you have it. I took a 3/8" thick steel plate and bored a hole just big enough to slip over the spindle (that's that hard part, getting that plate ready). Then I put some standoffs between the plate and the knuckle (deep-well impact sockets work great for this) and tightened a spindle nut on it as tight as I reasonably could (you don't have to go nuts with an impact wrench or anything, just get it tight with a breaker bar). Then take a big hammer and whack the plate right on top of each standoff. Hit each one two or three times. Then retighten the spindle nut, re-whack on the standoffs and keep repeating that process. You might not get much movement of the nut each time, but anything you get is progress (and progress is good!). I've never had it take more than 5~10 minutes of this once I had it set up.
If/when you do get it apart, clean it up good with a wire wheel or something, and then use anti-seize liberally. They usually come off by hand the next time if you do this.
Bob
Sorry, no '80 - '86 Ford trucks
"Oswald": 1997 F-250HD crew cab short box, 460, E4OD, 4.10 gears
"Pluto": 1971 Bronco, 302, NV3550 5 speed, Atlas 4.3:1 transfer case, 33" tires
"the motorhome": 2015 E-450-based 28' class C motorhome, 6.8L V-10
"the Dodge": 2007 Dodge 2500, 6.7L Cummins