@ ninosdemente: As everyone else has said, midway sells the stem, expander and pin assembly for a little over 6 $.
For a long time, I've been doing the decapping and re-sizing in two steps. RCBS, Lyman, and Redding, all make universal decapping dies. I have a set of the redding's, but the one I use the most is the Lee universal decapping die. It's almost indestructible and costs about 12 $ now, from midway. When decapping in a separate step, you're not applying the same pressure you would from re-sizing, and you can easily feel if the pin is off center or hitting something it shouldn't. By decapping separately, you can run the expander rod higher in the re-sizing die so that there is little chance of hitting something.
And if I were replacing the decapping/expander rod, I would also get a tungsten carbide expander. Redding offers them for their dies, and I think the Lyman carbide expanders come with an adapter which allows them to fit RCBS dies. Carbide expanders are a bit pricey, but they will make your life a lot easier. No squawking, no need to lubricate, no neck stretching, and little effort. Although I've found that with light lubrication, the little effort reduces to no effort.