Things You'll Need
SAE socket set
Pliers (needle-nose and regular)
Drive belts on riding mowers take a lot of abuse by design. Most two-belt systems consist of upper and and lower belt systems; the upper belt system delivers power to the PTO (power takeoff assembly) and the lower belt assembly. The lower belt assembly delivers power to the rear axle. Because of constant starting, stopping and slipping of the rear wheels on wet grass, the lower drive belts must be inspected and/or replaced annually. Fortunately, MTD has made this job easy.
Park the mower on a flat. level surface and set the parking brake firmly. Turn off the ignition, pop the hood of the tractor and disconnect the sparkplug wire (it just pulls free by hand). Lower the mowing deck to the low position, using the deck lift lever.
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Disconnect the front and rear mower deck supports by removing the retaining cotter pins, using pliers, then slide the deck forward to remove it. Remove the PTO drive belt shield with a Phillips screwdriver, then disconnect the PTO belt from the mower deck by hand. Remove the mower deck from beneath the mower (slide it out the left side of the tractor).
Lift the seat, then remove the battery. Beneath the battery box, loosen the 7/16-inch nut securing the transaxle pulley to the transaxle, using a 7/16-inch socket. Disconnect the transaxle pulley spring from the anchor bolt (left side of tractor), using needle-nose pliers.
Twist, then remove the PTO belt from the transaxle pulley, then remove it from the mower. Remove the screws that secure the belt guide to the variable speed pulley bracket, using a Phillips screwdriver. Carefully slip the belt from the variable speed pulley. Remove the belt guard around the engine pulley, using a 1/4-inch socket.
Remove the bolt, lock washer and flat washer holding down the crankshaft pulley, using a 1/2-inch socket (secure the pulley before removing the bolt). Remove the crankshaft pulley. Carefully remove the drive belt from the mower, twisting, then easing it toward the engine.
Install a new drive belt, following the reverse procedures used for belt removal.