If you have a John Deere riding mower, you can maintain its efficiency by keeping the blades sharp. Changing the blades on all mowers is inevitable; sooner or later they'll need sharpening or replacement. Dull, nicked, or damaged blades require immediate attention. Sharp mower blades help avoid excess wear and tear on the mower's engine and working parts. Pulleys and bearings take a lot more abuse when worn blades are fighting to cut the grass.
Park the mower on a flat surface. The lawn is fine as long as it's fairly level.
Pull the lever to lift the mower deck to its highest position. This is also called the transport position.
Place a piece of wood on each side of the mower deck to keep it from lowering while you're working on it.
Take your other piece of wood and use it to interrupt the blade from going around while you loosen the mower blades. Place it between the mower blade and the mower deck. Use the 5/8-inch wrench and loosen the bolt at the center of the blade. Be careful not to run your hand into the blade as you loosen the bolt.
Notice the order that you take off the washers and blade. The order should be a bolt, a washer, the blade, another washer, and then the deflector cup; which you don't need to remove. Remove the bolt, washers, and blade.
Examine the blade. If the blade is dull, have it sharpened and balanced. If the blade is damaged, get a new one.
Before placing the blade on the mower verify that the deflector cup is in place. This cup keeps grass from winding around the spindle that holds the blade on. It is located between the mower deck and the mower blade.
Be sure to position the blade with the cutting edge at the lowest level as you place it onto the mower. Replace the washer, blade, and washer in the same way that you removed them. Now put the bolt on and hand tighten it.
Put the block of wood on the other side of the blade so that it will hold the blade as you tighten the bolt. Put the 5/8-inch socket on the torque wrench and tighten the bolt to 75 Newton meters (or 55 foot pounds). Be cautious once again not to run your hand into the blade as you tighten it.
Repeat this method on the other blades as needed to change all of them. Some mowers have two blades and others have three.