You can try to WD-40 on the screw but its probably bunged by now. If you are going to change out the cap and rotor, I think you might as well break the damn thing.
2013 WRANGLER SPORT 2 DR., V-6 ,AUTO,HARD TOP
)1994 Jeep Wrangler 2.5L, Bestop top
/w steel half door and slider windows
5 speed, 2.5" lift, 31" tires,rack lights