i'm replacing my cap and rotor, and i cant figure out how to get the rotor off (just the plastic piece that comes in a cap and rotor kit). by looking at the new one, it appears that it just pulls straight off, but no matter how hard i pull, it wont come off. is there some retaining mechanism that i'm overlooking? do i need to pull the entire distributor out, or should i be able to do this just by removing the cap first?

No, it does pull straight off. If theyre real old, they tend to get stuck on the shaft. Keep tugging or try to lightly pry it up with something. I mean, the distributor shaft is metal and the rotor is plastic, so worst case scenario, you could just cut the damn thing off.

Exactly. I had to tug like crazy on mine, I'm not sure how old it was, but it definitely put up a fight. They're SUPPOSED to just "pop" right off, but they do get stuck on there after so long.

i finally got it off by prying it with a screwdriver. PITA!!

i noticed the metal underneath was rather rusty. i did my best to clean it real quick with PB Blaster, but didnt go crazy with it. should that be all shiny, or does a little rust not matter?

A wee bit of rust is no biggie. Just hit it with some WD40 and then wipe it down real well with a clean rag. You might also want to put a dab of dielectric grease on it so next time it isn't so hard.

Mine pulls off real easy.

when i run into a rotor that doesn't want to come off, i give them a good twist to shear off the little plastic guide piece inside of them & then they come right off. you do have to push out the piece of plastic from the slot in the shaft before you put the new rotor on.
i put a small dab of grease on the shaft to make it a little easier to remove the rotor next time.

I usually just break them off. They can be a royal pain. I also remove the little metal tab on the inside of the new rotor so it doesn't also get stuck in the future.