How to Replace Riding Mower Blades

What You'll Need
New riding mower blades
Torque wrench
Socket and open wrenches
Pieces of scrap lumber
Heavy leather work gloves
Tarp or old blanket for parts
Clean rags
Wire brush

Even after years of care and maintenance, you will need to replace your riding mower blades once they are worn out or become damaged due to an accident. Follow these tips below to change your riding mower blades quickly, easily and safely.

Step 1: Purchase the Correct Blades for Your Riding Mower

Find a dealer or distributor who carries replacement parts for your particular riding mower model, or order them from the manufacturer at their website.

Step 2: Prepare Your Riding Lawn Mower for Repair

Lay out a tarp or old blanket to set parts on. Gather your tools. Bring the riding lawn mower onto the work surface. Turn it off and set the parking brake. Remove the lawn mower battery to prevent accidental start up of the riding mower while you are working on the blades.

Step 3: Remove the Lawn Mower Deck

Put a piece of scrap lumber under the front and rear of the mower deck. Use the deck lever to lower the mower deck to the floor. Unscrew any attachments, such as the clipping bag, from the deck. Release the front and rear deck fasteners. Raise the deck again, and remove the scrap lumber pieces. Pull the deck out carefully from under the mower while wearing leather work gloves so you do not cut yourself on the blades or other attachments.

Step 4: Remove the Blades from the Lawn Mower Deck

Wedge another small piece of scrap lumber between the blades and the deck cover. Turn the mower deck over, and remove the blade drive belt. Use a socket wrench to remove the large bolt that holds the mower blades on the blade shaft. Place the bolt and all washers on the work surface in the order you removed them so you can replace them correctly.

Step 5: Clean the Mower Deck

Wipe all loose grass, sand and other dirt off the mower deck and its cover. Check for any signs of rust. Use a wire brush to clean any rust spots off the deck and cover.

Step 6: Install the New Mower Blades

Consult your owner's manual for correct placement of the new blades so they are sharp-side down when the mower is upright. Insert washers and bolts in the correct order and tighten the bolts with your fingers. Put a scrap wood wedge between the deck cover and the blades to hold them still and apply torque with a torque wrench to tighten the bolts to the proper tension. If you don't have a torque wrench, use a socket wrench to tighten the bolts until the washers are flat, then turn 1/8 of a circle more.

Step 7: Reassemble the Riding Mower

Reattach the blade drive belt and refasten the deck to the riding mower. Turn the mower upright and reinstall the battery. Release the parking brake, push the mower over to the lawn, and start it to check the blades are working properly.