how do u adjust the chamber

so on this site somebody said u can adjust the chamber to lay on 18s i want to know how to adjust the chamber i have 18s but it wont lay, it will on 16s , so anyway i need help

Camber is adjusted by pushing in or out of the upper control arms. To do this, you add or remove shims between the frame and the bar on the upper control arms. To adjust camber without adjusting caster, add or subtract equal amount of shims to both bolts. Is the rim hitting the fender or wheel well? Didn't bag my truck and only got 15s on it but knowledge from school, not first hand.

I'm laying on 18s but I had to tub the inner fenders, pie cut the upper control arms, bag it and get drop spindles. I didn't touch the shims except to remove and put back in.

ya my truck can lay on 18s too. i think you need to pie cut your upper control arms and get drop spindles if you dont allready have them.