January 01, 2015

How to replace a riding lawn mower blade

This step-by-step riding mower repair guide shows how to replace a blade on a riding lawn mower. A dull or bent mower blade tatters grass tips rather than making a clean cut, leaving the lawn looking dull. And a bent blade creates vibrations that can damage the mandrel assembly. Replace the blade with a manufacturer-approved lawn mower part if it's dull or bent.

The steps in this repair guide and video will help you replace the blade on Craftsman, MTD, Troybilt, Husqvarna, Toro, Murray, Ariens, Snapper and Weed Eater lawn tractors and riding mowers.

Quick links

Video

Instructions

Tools required

Wrench set

Wood block

Torque wrench (optional)

Work gloves

Repair difficulty

Time required

30 minutes or less

Replacing a blade on a riding lawn mower

This video explains how to replace a blade on a riding lawn mower.

Instructions

01.
Disconnect the spark plug
Park the tractor on a level surface and set the parking brake.
Turn the ignition switch off and remove the key.
Wear work gloves to protect your hands.
Lift the tractor hood and disconnect the spark plug wire.

Tip: Disconnect both spark plug wires if your tractor has 2 cylinders.
PHOTO: Disconnect the spark plug.
02.
Remove the mower deck
Lower the mower deck to its lowest position.
Disengage the cutting blades.
Roll the blade belt off the engine pulley and release the belt from the belt keepers.
Remove the front lift link support retaining pin and washer and then detach the support from the deck.
Remove the left suspension arm retaining clip and washer and then detach the arm from the tractor frame.
Remove the left rear deck bracket retaining clip and washer and then release the bracket from the deck.
Repeat the process on the other side of the deck to disconnect the right suspension arm and right rear deck bracket.
Pull the deck out far enough to access the blade cable attached to the deck.
Release the locking tabs and pull the blade cable out of the deck bracket.
Disconnect the blade cable spring from the idler arm and move the cable aside.
Pull the deck out from under the tractor frame and flip it over.
Tip: On some tractors, you can replace the blade without removing the mower deck.
Warning: After you disconnect the rear lift links, the spring-loaded attachment lift lever exerts more tension on the lever so don't use the lever until you reinstall the mower deck.
PHOTO: Remove the mower deck.
03.
Remove the old blade
Put a wood block between the blade and mower deck to keep the cutting blade from moving.
Remove the blade mounting bolt and pull off the cutting blade.
PHOTO: Remove the blade.
04.
Install the new blade
With the correct side of the blade facing up, attach the blade to the blade shaft and hand tighten the blade bolt.
Put the wood block back in place and tighten the blade bolt firmly.
Remove the wood block and flip the deck upright.
Tip: The lower side of the blade is clearly labeled for easy installation.
PHOTO: Install the new blade.
05.
Reinstall the mower deck
Push the deck near the tractor frame.
Connect the blade clutch cable spring to the idler arm.
Push the blade clutch cable retainer into the deck bracket and engage the locking tabs.
Position the deck under the tractor frame.
Reconnect the front lift link support to the deck using the washer and retaining clip.
Reconnect the left suspension arm and deck bracket using the washers and retaining clips.
Repeat the process to reconnect the right suspension arm and deck bracket.
Route the blade belt through the belt keepers and roll the blade belt onto the engine pulley.
Check the blade belt routing on the mower deck and adjust the blade belt if needed to route the belt over all pulleys and through all belt keepers.
Tip: Refer to your owner's manual for more on routing the blade belt.
PHOTO: Reinstall the mower deck.
06.
Reconnect the spark plug
Reconnect the spark plug wire and lower the tractor hood.
Tip: Reconnect both spark plug wires if your engine has 2 cylinders.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.