Unplug the power cord of the Whirlpool Cabrio dryer from the power source before attempting to replace the idler pulley.
Slide a flat head screwdriver between the lower front access panel and the dryer cabinet on both sides of the cabinet, and pry away from the cabinet to detach the plastic clips on the face of the dryer cabinet from the lower panel. The dryer includes an upper and lower access panel in the front of the cabinet. You only need to remove the lower panel to get to the idler pulley.
Locate the idler pulley near the front of the dryer cabinet on the bottom and move the idler arm forward to relieve the tension on the dryer belt. The idler pulley is a plastic pulley wheel on the top of a metal spring-loaded bar that sits next to the motor. Take the belt off the idler pulley by hand when the tension is released and let the pulley move back into its original position. The idler pulley metal bar acts as a spring and moves back into place on its own.
Lift the idler pulley assembly up toward the dryer drum to detach the metal tab on the assembly from the dryer base, and slide the assembly out of the open slot in the bottom of the dryer cabinet by pulling it toward you. Take the idler pulley assembly out of the dryer cabinet and dispose of the part.
Slide the bottom bar of the new idler pulley assembly into the open slot in the bottom of the dryer cabinet and push down to set the tab into the hole in the dryer base to lock the assembly into place. Move the idler arm forward and place the dryer belt around the idler pulley by hand.
Verify that the belt is routed around the dryer drum and check to see that there are no twists in the belt. Let the idler arm move back into position to add tension to the belt. Place the lower front panel on the dryer cabinet and push on both sides to attach the panel to the plastic clips on the dryer cabinet.
Plug the dryer into the power supply.