Pull the 4 king pin bolts, then swing the knuckle to the stop and use a large crescent or pipe wrench to spin the king pin breaking it loose. You can then get underneath it with something to pry up (screw driver, pry bar, chisel). Be careful on the top ones, there will be shims under the king pin that you will want to try and save. Not a bit deal if you can't save them, you will need to get a king pin shim kit to reset the preload anyway.