do the bearings have to be pressed in?
My advise, unless there is a problem with the bearings, just get new king pins (that were made to be 8mm king pins not 5/16ths bolts) and leave it at that.
FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience