Riding lawn mowers have several blades under their decks, each one in need of regular maintenance. When cleaning the mower deck, it is best practice to look at the state of the mower blades to ensure they do not need sharpening. If there is a series of large gashes along the blades, or if they are bent, the blades should be replaced. Mower blades require replacement with the correct model to prevent mechanical failure or injury to the driver.
Place the mower on a flat surface and engage the parking brake to keep the mower from rolling. Disconnect the spark plug and remove the key to prevent the mower from starting. Disengage the battery, first removing the black cable then the red, negative then positive.
Clean the mower deck of any loose clippings using a soft brush or pressurized air.
Remove the mower deck, following the instruction of your mower. Usually there are two clasps on either end of the mower that release the deck when pulled. Disengage the parking brake and roll the mower onto wheel ramps if the mower deck is not removable. Place wood blocks or bricks behind the wheels and engage the parking brake to keep it from rolling
Secure the blade against a wood block by wedging the blade into it until it will not move.
Remove the blade by unscrewing the socket holding it in place using the socket wrench. Put on the new blade and reassemble as necessary. Test the mower.