Originally Posted by Danthurs
Yes, you can change just the pulley. I do believe it is a reverse thread bolt.
Correct. This repair is "do it in the Advance parking lot" easy, which is where you and a $20 bill should go for a new idler pulley.
Just push the tensioner arm back and slip the belt off, then, because it'* reverse-threaded, turn the 15mm bolt hard clockwise
to loosen it. Slap on a new pulley (and a new bolt, if the pulley came with one), put the belt back on, and go home.