Unless you're really lucky you'll probably need to use a fair amount of force to get the kingpin out. So having the brake backplate out of the way will be a big help to you when you need to get a big punch or drift in there.
Each kingpin is held in place by a tapered cotter pin. there's a nut on the end of this pin behind the axle eye. Undo the nut and drive the cotter pin out through the front of the axle eye with a punch.
Last edited by Stuart_Giles; 02/19/2012 12:42 PM.