BD Diesel Control Arm Caster Adjusting Cam - Ford 2005-2010 6.0L/6.4LAlterations to the drivetrain such as installing a suspension lift or a simple level lift can cause the steering pivot axis and tire position to swing rearward making the caster negative resulting in potential wandering, wobble, pulling, stiff steering or even the inability to keep your truck on the road. Even larger tires can exaggerate the problem and require more positive castor. Caster is the angle to which the steering pivot axis is tilted either