1955-2nd Shop Manual king-pin replacement instructions. As described by CASO, check "Disassembly": the king pin plug stakes have to be chiseled out/away - there is a top/bottom plug that had been
"staked" into place.
I have only once been able to knock out the king pins with the axle on the truck. All other times, I have had to remove the axle and use a hydraulic press (or, take the axle-assembly to a truck shop) to remove the king pins. After the king pins are removed, the floating 1/2 ton bushings should then come out fairly easily.
You could try a bigger breakfast and a bigger hammer - you have nothing to lose.
Update:
I second the need to remove the axle to remove the king pin.
1/2 ton's all originally had floating bushings making it possible to remove them with a good breakfast and at least a MFH AND a vice.... and some Kroil or ATF.
I found the key is to place the piece so it rests ON the vice not suspended in the jaws. I still used the jaws to hold it steady, supporting the other end with my adjustable roller, but made sure it was solid against the vice (or your chosen block of Al) on the bottom of the knuckle. I tried several times with the axle just in the jaws and thought "no go" but when I realized the forces were being dispersed the wrong way and supported the knuckle on the bottom, the pin started moving after half a dozen blows with a 3 lb jack, my 1/2" x 6" 'stovebolt with the head ground down to fit' drift and some Kroil.
SAVE THE KING PIN for when you do the springs! It makes a great perfect size drift for the spring bushing removal!
