Check out
http://www.autobarn.net/xxx7005.html but don't buy it, Autozone, Oreilly have the kits you can rent to pull them. In the pic the crome looking piece comes apart to expose to halves that fit around the pulley nose, then use the stud to work it off, pretty tight, Plastic I think. It's all a friction fit. To put the pulley on most pumps have the bolt, nut and washer to push it back on. Looks like some aftermarket type pumps have a wagon wheel pulley. Most of them are chrome type replacememts.
BTW, just when you think you're going to bust something, it'll start to move and begin to come off, you'll have to use the pulley the whole way.
Good Luck,
Rob