Drive your MTD onto solid ground, turn it off and set the parking brake. Remove the spark plug wire to prevent the mower from coming on while you work on it.
Locate all three mounting brackets for the mower deck on the right, left and front of the mower deck. Remove the hex-head bolts that hold the brackets in place with a socket set.
Lift the driver's seat forward to locate the battery. Disconnect the battery cables with a socket and pull the battery out of the battery box. Place the battery off to the side.
Remove the bolt that holds the trans-axle pulley onto the trans axle with a socket. You can easily locate the pulley by looking down though the hole in the battery box.
Disconnect the anchor bolt spring mounted on the left side of the mower deck with a spring puller. When you disconnect the spring, tension on the belt loosens.
Remove the belt from the trans-axle pulley, then remove the belt from the mower deck. If needed, make a diagram of the belt routing before you remove it.
Place the new belt onto the pulley system on the mower deck and then place the belt onto the trans-axle pulley.
Reconnect the anchor bolt spring and then tighten the bolt on the trans-axle pulley.
Place the battery into the battery box and reconnect the battery cables.
Reconnect the mounting brackets on the mower deck to the underside of the MTD tractor.
Reconnect the spark plug wire to the spark plug.