Replacing the mower deck belt on any riding lawn mower is a necessary evil. After time and use, the belt will become dry and begin cracking. While always having a belt replacement is a good idea, not everybody thinks of it until the belt breaks and they need one. There are many makes and models of riding lawn mowers that require a variety of procedures to replace the mower deck belt (and other drive belts). Always refer to the owner's manual for the correct instructions to replace the mower deck belt on your particular riding lawn mower.
Things You'll Need
Ratchet and socket set (or)
Hand wrench set
Remove the grass catcher assembly from the lawn mower if applicable.
Lower the height adjust handle (if applicable) and the hydraulic piston (if applicable) to put the deck in its lowest position for removal. While not all riding lawn mowers require the removal of the deck to replace the deck belt, it is easier to access the belt for removal and replacement than it is on the tractor.
Push the idler arm handle to release the tension on the deck belt and remove it from the PTO (electric clutch) pulley located under the tractor.
Remove the deck per the instructions in the owner's manual of your riding lawn mower.
Remove the belt stop assembly (if applicable) using a ratchet and socket or a hand wrench.
Remove any pulley shields that may be present on the deck using a ratchet and a socket or a hand wrench to remove the bolts.
Remove the old belt. Install the new belt. Be sure that the V-side of the belt is inserted into the pulley grooves and you route the belt the same way it was removed.
Replace the pulley shields and bolts if applicable.
Replace the belt stop assembly if applicable.
Reinstall the mower deck to the tractor and install the belt to the PTO pulley by relieving tension of the idler arm pulley handle again. Replace the grass catcher assembly if applicable.