You mean the "bolt" on the pulley? I only needed my short little 3/8" ratchet to get mine off. If an impact won't get it off (Well a good impact, like an IR
) you're sol.
Don't heat the bolt, it will just expand and make it harded to get out. Try some WD-40 or Liquid wrench. Then try a big impact again, something with 500-700 ft lbs of torque.