First off the pitman arm doesn't leak. The sector shaft leaks & runs down on the pitman arm. There are 2 seals & a spacer & snap ring for that shaft. It all comes in a kit. After pulling the pitman arm like you described, the best way is to put the steering on center & pull the sector shaft out by removeing the 4 bolts on top. I think some guys dig the seals out with the shaft in but its easier & cleaner to pull it. This can usually be done with steering box in the truck but sometimes you need to pull it depending how assessable it is.