The best way to remove the old king pins is:
#1 Take out king pin lock pin
#2 Take punch and drive it through plug cap and pry out plug (i usually do the bottom cap.
#3 Take axle and set it on jack stands (I set the stands under spring perches with axle drop down)
#4 Take air chisel and put in a punch end.
#5 Set on axle and let the air chisel do the work
#6 If the king pins don't move use some heat and repeat #5
Also I wanted to let you know there are some differences in spindles 41-54 Most are miner. Check out my web site article
http://droppedaxles.com/TECH_ARTICLES.htmlIf your spindle bushings are wore out Moog makes a oversize bushing king pin kit. I use them all the time because 90% of the spindle king pin bushing holes are loose.