Mine does that also, I changed mine all out to Allen bolts and keep a Allen wrench in the glove box and tighten them after every day of wheelin. I even have lock washers on them. Maybe try studs with lock nuts.

Dennis

95 Sportage, gone but not forgotten.
98 Jeep TJ, 4" Zone springs with RC Long arms, Ford 8.8", 4.56 gears & Detroit locker rear, D30, 4.56 & Detroit Trutrack front.