question pertaining to brakes

okay, i bought some rotors for my 89 F-250, i tried to remove the old ones, i failed because i could not get the hub off. i took the knob and chrome peice off, but still could not figure out how to get the rotor off. i was told by a friend that there was a tool that did this. i would like to know what the tool is if there is one and how to use it? thanks for any replies.
After you pull the outer hub,then there are two snap rings,one inner and one outer to remove the inner hub.Use one of the hub bolts to pull it out by hand.After that you need a special socket for the wheel bearing adjustment nuts,but sometimes a long screwdriver and hammer (be gentle) work just fine.After they are off,the rotor slides off.Some parts stores will loan or rent you the tool.Make sure you get the right one,as there are two different sizes for the F-250 based on which axle you have.If it's a light duty 250,then you need the smaller one,the HD one is larger.Becareful going back together,as the lock ring for the bearing adjusment is very important.When you reassemble,put the rotor on with the bearings,then the adjustment nut with the little pin facing towards you.Adjust the bearing preload,and then put the lock ring in so that it aligns in the keyway,and one of the holes goes over the little pin.This prevents it from loosening.Now finally the second nut to hold it all together.This would also be a good time to service the spindle bearings,seals,axle u-joints etc,as you are half way there.