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How to Remove a Lawn Mower Blade: Installing Mower Blades

Authored by Tractor Supply Company

Lawn mower blades dull over time, making it hard to get that perfect cut. While there are lawn mower blade replacement services out there, a little elbow grease can help you save money by replacing them at home. Pick up the necessary lawn mower supplies and follow these steps on how to remove a lawn mower blade and replace it with a new one.

What to do before changing a lawn mower blade

Most lawn mowers follow the same steps for changing a blade but, check your mower’s user manual before getting started. You may also want to confirm the following before changing mower blades:

  • Blade style: Most lawn mower blades are universal, but some mowers require a unique style. Check your manual or look to see which blade is currently on your lawn mower and use that as a guide when buying new mower blades.
  • Bolt size: The bolts used to secure lawn mower blades are often 1/2 inch, 5/8 inch, or 3/4 inch. Make sure you have access to a socket wrench that works with the size of bolts on your mower.
  • Regular or reverse-threaded bolt: Standard bolts follow the universal "righty-tighty, lefty-loosey" guide. However, some lawn mowers are reverse-threaded, meaning you turn right to loosen and left to tighten. Confirm which direction you'll need to turn the bolt when you remove the lawn mower blade.

Replacing push mower blades

These steps can help assist you with a push mower blade replacement:

  1. Disconnect the spark plug and ignition wire. This is an important safety precaution to take before you remove a mower blade.
  2. Siphon out the gas. Transfer gas that's currently in the lawn mower to a fuel container. Otherwise, fuel may spill out and cause a mess while you work.
  3. Allow access to the underside of your mower. Raise your lawn mower on a lift or carefully lay it on its side. You can also take this time to wipe any grass and dirt residue from the blade with a handheld brush.
  4. Put on gloves. Lawn mower blades are sharp, so you'll want to keep your hands protected.
  5. Loosen the retaining bolt on the blade. Use a socket wrench, turning left for a standard bolt and right for a reverse-threaded one. Consider placing a wooden block under the blade to prevent it from moving around.
  6. Replace the lawn mower blade. Once the retaining bolt is off, the old blade will also come right off. Put the new blade on, making sure it's correctly aligned. Most blades include printed directions such as "this side up" or "grass side."
  7. Tighten the retaining bolt. Put the retaining bolt back in place and tighten it. Ensure the blade doesn't wobble — if it does, screw the bolt tighter. Take extra care during this step, as the new blade will likely be much sharper than the old blade you removed.
  8. Reset the lawn mower. Turn the lawn mower so it's upright, replace any fuel you siphoned out earlier, and reattach the spark plug and ignition wire.

Now you're ready to get out and give your lawn a perfect cut.

How to replace lawn mower blades on a ride-on mower

Ride-on mowers follow a similar process but require a few extra steps:

  1. Turn off and unplug the mower. Remove the key and unplug the spark plug for safety.
  2. Lower the mower deck. Set it to the lowest point it can go.
  3. Remove the mower deck. Disengage the blades and release the blade belt. Unscrew all the bolts and brackets that connect the mower deck to the main body of the lawn mower. (Remember to keep note of where everything goes, as you'll need to replace these bolts and brackets when you're done.) Disengage the blade cable, and the mower deck will slide out from under the ride-on mower.
  4. Flip the mower deck over and change the blades. Follow steps five through seven from above to change the mower blades.
  5. Replace the mower deck and reconnect everything. Flip the mower deck back over and replace the bolts and brackets to reconnect it to the main body of your lawn mower. Raise it back up, put the spark plug back in, and you're good to go.

Keep these easy steps in mind, and you'll never have to pay for a blade replacement service again. Tractor Supply Co. is your shop for mower equipment and the tools you need to achieve a beautiful, healthy lawn.