on my 58 apache ,I replaced the whole pillar just above the top hinge down to the step. That upper flange over the pillar can be separated with a mutilsaw tool. I would not try and drill out the original welds. That fender bolt hole placement is crucial
~ BD. "You won't find me in an old folks home" Pioneer Florida Cracker 1958 Apache Stepside 1958 Apache 1/2 ton Panel 1959 Apache 1/2 ton Panel