Hi, Folks.
You can 'ackshully' make your own wrench for adjusting these fan pulleys. It requires two arms set apart by slightly more than the diameter of the center threaded section of adjustable side of the pulley and attached to one handle.

Each arm needs to have either a pin embedded into the end of it or the end of the arms turned downward at right angles to the handle so that they can engage the ribs radiating out from the center to the outer edge of the pulley. Place one side behind one rib and the other side ahead of the opposite rib depending on whether you need to loosen or tighten the belt.

This eliminates the need to start beating on things that were never made to be beaten on.

BUTTTTT, what would I know??? I'm 'justa pore, dumm bulldozer op'rator', not wunna them smart 'wrenchbender' types who get to 'revive' what us op'rators kill.

Just my 0.02.