How to Change The Blades on a Zero-Turn Mower

Over time, the blades on your zero-turn riding lawn mower can become worn out, bent or dinged. This gradual damage can reduce the effectiveness of your mower, so be sure to sharpen or replace the blades if you notice these signs of wear. How often you visually check the blades depends on how regularly the mower is used. Check the blades at least twice a year, at the beginning and middle of the mowing season, or more often if you mow year-round. This video will show you how replace the blades on your Cub Cadet Ultima zero-turn mower. Depending on your model, the instructions in this video may vary slightly. Always be sure to check your operator's manual for detailed instructions.

INSTRUCTIONS

Step 1: Prepare your Ultima zero-turn mower for maintenance. Place your mower on a flat, level surface. Turn the mower off and make sure the engine is cool.  Remove the ignition key, disconnect the spark plug ignition wire, and engage the parking brake. This helps ensure the machine doesn't start accidentally and cause you or those around you harm.

Step 2: Set your mower’s deck height to the lowest setting.

Step 3: Remove both belt covers. Use a 3/8” socket or wrench to remove the belt covers from the deck. Remove all 6 screws.

Step 4: Remove the access panel. Using a 1/2” socket or the panel access tool included with Ultima models, remove the bolt from the panel.

Step 5: Remove the belt from the spindle pulleys. Using a 9/16” socket or wrench pull the idler pulley arm back to release the belt tension.
 
Step 6: Remove the belt from the idler pulleys and PTO clutch. Using both a 9/16” socket and wrench loosen, but do not remove, the idler pulley bolts.

Step 7: Remove 3 cotter pins and deck pins that secure the deck. With the pins removed the deck can be slid out from under the mower.

Step 8: Carefully flip the deck over to access the blades

Step 9: Remove the blades. Wear gloves for protection.  A block of wood or the Arnold Blade Removal Tool (490-850-0005) can be used to stop the blades from rotating. Use a 15/16” socket or wrench to loosen the blade nuts.
 
Step 10: Replace the blades. Carefully replace the blades and tighten the nuts securely per the specifications in your owner’s manual. When properly installed the word bottom or the blade part number will face the ground.

Step 11: Reinstall your cutting following the steps in reverse order. Flip the deck over and carefully slide the deck back into place under the mower.

Step 12: Reattach the deck. Slide the deck pins back into place and reconnect the cotter pins.

Step 13: Reinstall the belt. Place the belt in position as per the routing diagram.

Step 14: Route the belt around the PTO clutch.

Step 15: Route the belt through the idler pulleys. Using both a 9/16” socket and wrench tighten both of the idler pulley bolts.

Step 16: Route the belt around the spindle pulleys. Use the 9/16” socket or wrench to release the tension and finish routing the belt.

Step 17: Reinstall both belt covers,

Step 18: Reinstall the access panel and bolt

Step 19: Reconnect your spark plug wires

Use our parts finder to locate and order any replacement parts you may need for maintenance. Refer to your owner's manual for additional maintenance information.