January 1, 2015

How to replace a riding lawn mower blade

By Lyle Weischwill
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 replacement 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
Tools required
Wrench set
Wood block
Torque wrench (optional)
Work gloves
Repair difficulty
Time required
30 minutes or less
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

  1. 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.
    Disconnect the spark plug.

    Disconnect the spark plug.

  2. 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.
    Remove the mower deck.

    Remove the mower deck.

  3. 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.

    Remove the blade.

    Remove the blade.

  4. 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.
    Install the new blade.

    Install the new blade.

  5. 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.
    Reinstall the mower deck.

    Reinstall the mower deck.

  6. 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.

Symptoms common to all riding mowers & tractors

Choose a symptom to see related riding mower and lawn tractor repairs.

Main causes: dead battery, stale fuel, bad starter solenoid, ignition system problem, bad ignition interlock switch, clogged carburetor
Main causes: damaged cutting blade, worn deck pulley, damaged mandrel pulley, loose fasteners on mower deck components
Main causes: shift lever needs adjustment, neutral control needs adjustment
Main causes: engine overfilled with oil, leaky head gasket or sump gasket, damaged carburetor seals, cracked fuel pump, broken fuel line
Main causes: punctured tire or inner tube, leaky valve stem, damaged wheel rim
Main causes: worn or broken ground drive belt, bad seat switch, transaxle freewheel control engaged, transaxle failure, dirty carburetor
Main causes: unlevel mower deck, dull or damaged cutting blades, worn mandrel pulleys, bent mower deck, engine needs tune up
Main causes: worn or broken blade belt, broken belt idler pulley, blade clutch cable failure, bad PTO switch, damaged mandrel pulleys
Main causes: clogged carburetor, damaged flywheel key, dirty spark plug, stale fuel, improper valve lash, engine needs a tune up

Repair guides common to all riding mowers & tractors

These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.

How to replace the air filter on a riding lawn mower

Get your mower running smoothly again by replacing the air filter—it's a quick job you can do yourself, following these steps.

Repair difficulty
Time required
 15 minutes or less
How to replace the starter motor on a riding lawn mower

If you hear the solenoid click but don’t hear the starter motor spin when you turn the key, follow these steps to replace it.

Repair difficulty
Time required
 30 minutes or less
January 1, 2015
By Lyle Weischwill
How to replace a riding lawn mower blade

If a blade on your mower is dull or bent, replace it following the steps in this repair guide.

Repair difficulty
Time required
 30 minutes or less

Articles and videos common to all riding mowers & tractors

Use the advice and tips in these articles and videos to get the most out of your riding mower or lawn tractor.

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