Lose weight? Don't let fat chicks drive you rig? Add an extra leaf or change the springs with more leaves to make it more ridgid. You may also have body mount issues that the bushings have deterioated and replace with poly mounts.
When I first bought my jeep the PO had a smaller tire on the drivers front, so that's what I thought was causing the lean.....but nope, after a resto and new tires it seems to be in the frame like other posters have said. Whether due to frames being stacked and tightened down on rail cars to whatever the other suggested reasons were, my drivers front is about 1 1/2" lower than the rest of the jeep. I used spacers above the body mounts to bring it up a little bit and make it less obvious, but I'd love to hear a more effective solution. Jack up the outside seat mounts a little so at least you sit straight up and down?
CJ7, 258, Dana 20 T-case, Dana 30 & AMC 20, TFI Ignition upgrade, MC 2150 carb, YJ tub mod
For years, dealers installed shims under the HIGH side spring to fix this when a customer complained. My wife bought our jeep new in 75, and it after a while took it to the dealer with the problem.
Last summer, I replaced the worn out springs with new stock height ones, and found a 1/2" steel shim under the driver's rear spring. When I replaced with new springs, I reused the shim, just to see what would happen. I was fully prepared to remove the shim if necessary because of the new springs.
Turns out I saved myself a little work by reusing the shim. The jeep sits to within 1/8" of level with the shim installed. Good enough for me.
This tells me that whatever the cause of the problem, it is not in the spring packs, or the shim would have been unneeded with brand new springs.
So as far as I'm concerned, I don't know the cause, but the old dealer installed solution has negated the problem for 34 years now.