Like crabman said.....
BS, I used the kit from Fixin Rams site. It is way more money (about 60 bucks) than just the seal kit from cummins, but worth every penny. He sends a dvd that shows in great detail, how to service the vac pump once you have it out of the vehicle. Also, included are some seal driving tools(pvc pipe,ftngs) that work great for removing the old seal and installing the new one. The kit comes with seal, o-rings, and a new gasket for the vac pump to engine block. After removing the battery and the intake tube, it is fairly easy to remove and install the vac pump assy. No special tools needed, I just used wrenches, sockets, and a razor knife to cut the fluid lines on the pump. If you suck the ps pump dry before you cut the lines, it doesn't make that much of a mess. If you cut them right at the clamps, the hoses are still long enough to reattach, but probably only once. Others have done this job by removing the steering pump first to avoid cutting the lines but it is much easier to remove the vac pump/ps steering pump as one unit. Plus, your power steering fluid gets changed this way. Good luck!
Sam