John Deere manufactures a line of ride-on commercial lawnmowers with a 54-inch mowing deck, providing a wide cutting path to make quick work of expansive lawns and other grassy areas. A heavy-duty drive belt turns the blades within the deck and winds from the drive pulley on the motor to a pulley system that turns each mower blade. Over time, this belt will wear or sustain damage and will need replacing. Replacing the drive belt requires some disassembly of the mower to access the drive belt within the mower deck.
Park the lawnmower safely. Shut the mower off and allow the unit to cool down completely. Set the mower deck to the lowest possible setting. Unscrew the retaining screws and remove the mower deck shield and both belt shields from the mower.
Disconnect the idler spring from the idler arm. Remove the belt guide from the idler arm. Loosen the left mower pulley belt guides. Move the guide enough to remove the belt from the pulley system. Observe how the belt winds through the pulleys as you remove it.
Install the new belt in the same location as the old belt. Check that the belt fits properly to the clutch sheave, the spindle sheaves and all pulleys.
Reconnect the idler spring to the idler arm. Adjust the tension on the idler spring so that the spring length is between 216 and 226mm from inside of one hook on the spring to the inside of the other hook.
Reinstall the belt guide in the idler arm. Adjust the belt guides on the left pulley so they are within 6mm of the belt. Tighten the belt guide nuts.
Reinstall the mower deck belt shields and the mower deck shield. Set the mower deck to the proper height for your lawn. The mower is now ready to use.