I dont know whats the deal with this but I am having problem with this on my XJ
When I flex, the shackle dont drop very much due the the bushings dont actually made to have that MUCH of torsion movement.
the part that bother the hell out of me that after I jacked up right rear bumper with hi-lift jack to change the tire on right rear then i dropped it down. I was like what the hell, the XJ have MAJOR leaning right now. the right side's much higher than left side and the axle has been shifted to the right lot too.
What the deal? :soapbox:
shackles dont drop, they pivot. also dont over torque a bushing bolt and cause binding.
as for the lean, maybe you bent the bumper mount and the bumper isnt level??