Lower the deck with the deck lever mounted on the side of the mower deck. This increases the distance between the underside of the tractor and the topside of the deck.
Disengage the mower blades via the PTO lever located on the control panel just in front of the driver's seat. This creates slack in the mower belt.
Wipe off the mower deck with a wire brush to remove any buildup of dirt and grass. Over time, it is common for debris to build up on the deck. If you choose, you can hose the deck off with water and then wait until the mower dries.
Push inward on the idler pulley. The idler pulley bolts to a spring-loaded plate, which makes it easy to locate on the mower deck.
Pull the belt off the drive pulley located on the bottom of the engine and then pull the belt off the pulleys on the mower deck.
Place the new belt onto the pulleys on the deck and then place the belt over the drive pulley on the engine.
Push in on the idler pulley and then place the belt over the idler pulley. Let go of the pulley to add tension to the belt.