I would say its the mounting hardware for the pads. There are tension springs that help keep them centered and absorb the shock of directional change. It's possible it could just be at one of the pads. Wiser techs than I may have other ideas as well.
"-1988 Red Hilux Standard frame, X-tra cab, locked F&R, 5.29's, 35" tires and a SAS. In Moab
"-1988, 1999 3.4L, Supercharged, 2.1" URD pulley, URD 7th injector, 2 1/2" Magnaflow exhaust, TO DO: lift, locker.
"Did you know the IFS was designed by Hitler himself to make the life of 4WD owners tough? Yeah, it's true, he saw a vision of the Devil and he told him to do it." -DaveInDenver