How to replace a cutting blade on a zero-turn riding mower

This step-by-step repair guide explains how to replace a cutting blade on a zero-turn riding mower. Worn or damaged blades won’t cut the grass well, giving an uneven cut and tattering the tips of the grass. Inspect your mower blades regularly and, if needed, replace a damaged cutting blade with a manufacturer-approved riding mower part, using the steps in this guide.

Use this basic procedure to replace cutting blades in Craftsman, Husqvarna, Toro, MTD, and Cub Cadet zero-turn riding mowers.

Instructions

1. Disconnect the spark plugs

Disconnect the spark plug wires.

2. Release the blade belt

Lower the mower deck to the lowest cutting position.

Remove the left pulley cover on the mower deck.

Push the blade belt idler pulley in and roll the blade drive belt off the left blade pulley.

Reach under the rear of the mower frame and remove the blade drive belt from the electric clutch.

3. Remove the mower deck

Disconnect the mower deck mounting pins and release the hanging brackets from the mower deck.

Push the mower deck slightly forward and release it from the front bracket.

Pull the mower deck out from under the mower frame.

4. Remove the cutting blade

Flip the mower deck upside down to access the mower blade.

Wedge a block of wood between the cutting blade and the deck to keep the blade from turning.

Remove the cutting blade mounting bolt and pull the cutting blade off.

Warning: The cutting blades are sharp. Wear work gloves to protect your hands.

Tip: Turn the blade mounting bolt counterclockwise to remove it.

5.  Install the new cutting blade

Position the new cutting blade on the shaft and install the mounting bolt.

Tighten the bolt to 50 ft-lbs with a torque wrench.

Tip: If blade is marked with directions such as “This side up,” position the blade as marked.

6. Reinstall the mower deck

Flip the mower deck right side up.

Push the mower deck under the mower frame.

Reinstall the mower deck on the front bracket.

Reinstall the mower deck hanging brackets and secure them with the mounting pins.

7. Reattach the blade belt

Reinstall the blade drive belt onto the electric clutch.

Push in the blade belt idler pulley and roll the blade belt back onto the left blade pulley.

Reinstall the pulley cover.

Tip: Make sure that the blade belt is routed correctly when reinstalling the mower deck.

8. Reconnect spark plugs

Reconnect the wires on the spark plugs.