It is my experience with ball joints(granted, on Chevy's) that you don't realize they are bad till they start making noise or causing driveability issues, and by that time both the uppers and lowers on that side will be toast.
I did them on my 89 Suburban in November.. bought the truck for a song knowing it needed front end work. All 4 were bad beyond belief, I couldn't believe the previous owner drove the thing so long like that. Not to mention the spindle nuts were finger tight :Wow1: I think I spent a total of 12 hours doing both sides, that being my first time ever even pulling a hub/rotor assembly off, let alone a knuckle.
Now I gotta do them on my '91 V2500 Suburban.. the drivers side are the ones that are definitely bad, grabbing the tire at 12 o'clock and 6 o'clock I can shake the whole knuckle up and down. Passenger side feels tight, but they are getting replaced at the same time.
I don't know about a Super Duty with the unit bearing D50 fronts, but on the older stand bearing d44 fronts ball joints just took a lot of time and weren't all that technical. I would think it would be similar, other than removing the unit bearing and rotor assembly(no idea how that works on a unit bearing hub).
Don't know if you've got the truck back yet or not, but it's worth checking and making sure they aren't use chicom junk for your joints.. Spicer Pro-Grade or Moog are the only way to go.
