How do you replace the crankshaft pulley on a 1991 Chevy S-10 4.3L?

Answer 1

The pulley alone unbolts from the harmonic balancer (aka vibration damper). It's the harmonic balancer that requires a special puller to remove it from the crankshaft without doing any damage.

Answer 2

Disconnect the battery and remove the fan assembly and crankshaft belts. Remove the center bolt from the pulley and use a crankshaft pulley remover to pull off the pulley. You can usually borrow one from an auto parts store.