Strange negative camber

The camber effect I'm seeing on my '83 F150 4x4 with a 4" lift is a new one on me. I have spent some time sifting through camber and front-end posts here but can't find this issue reported. When I back up straight, like backing out of the garage and come to a stop, the front tires show some extreme (maybe 10 degrees) negative camber that is not there normally. The camber measures about neutral in normal operation and the truck drives fine in town and at speed on the highway. No strange behavior accelerating or braking.

I have checked the ball joints and they seem to be okay. They aren't new but are not original either. The tie rod ends, pitman arm, steering box are all tight. Apparently something is moving when you travel backwards but I can't detect what that is. Anyone seen this before? It seems like it has to be one or several bad ball joints but I'd like to confirm that before installing parts.

The truck is here for sale, but I'd like to sort this out first. https://forum.garysgaragemahal.com/FS-1983-F150-4x4-351W-4-spd-td126653.html

Many thanks for your thoughts...ned.

Sorry - I should have put this in the Suspension and Steering subforum. It would be great if someone could move it...ned.

When you back these trucks up you get negative camber, pulling it forward straightens it up, as you’ve seen.

It’s what they do, can’t remember why.

Ned - I don't think we have a subforum on Suspension & Steering meant for threads like this.  The one we have is in Resources & How-To's and is a catalog of links to threads people have found on specific S&S topics, like lifts or Saginaw pumps.

But if I'm wrong please point me to the one you have in mind.

Gary - I saw the Suspension & Steering How-To post of links at the top of this forum and mistook it for a sub-forum. Sorry for sharing my confusion. Nothing to see here, move along...ned.

Lol!  No problem.