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How to Replace a Craftsman Lawn Mower Drive Belt

Lawn mowers are great inventions--as long as they are working. One of the common reasons that a Craftsman mower stops working is that the drive belt fails. Fortunately if the problem is caused by a broken drive belt then getting your mower working again isn't terribly difficult.

Consult your owner's manual to get the proper part number for the drive belt needed for your particular lawn mower model and purchase it.

Turn your lawn mower on its side or put your riding mower up on blocks so you can get to the underside of your mower's deck.

Clean the underside of your deck. This can most easily be accomplished by carefully scraping the underside of the deck with a long handled flat blade screwdriver. Remove any pieces of drive belt that are still attached to the pulleys that are visible.

Locate the tensioner. This is a pulley that can move when it is loosened. Use your ratchet to loosen the bolt holding the tensioner in place. Allow the tensioner to move closer to the other pulleys.

Check your owner's manual for the proper way to position your drive belt over the pulleys. On most models the drive belt simply goes around the drive pulley, the tensioner and the pulley connected to the blades, but some models are slightly different.

Pull the tensioner tight until there is less than 1/2 inch of play in the drive belt when you push on it between pulleys. Tighten the bolt holding the tensioner in place once the belt is as tight as the owner's manual suggests.

Put A Deck Belt On A Craftsman Lawn Mower

Remove the old belt from the mandrel pulley located on top of the mower deck near where the cut grass discharges. Slip the belt off the pulley by hand. This pulley may have a small belt guide that looks like a narrow piece of metal sticking up beside the pulley. Wiggle the belt between the pulley and the guide to remove it. Work it down onto the pulley with your hands. Ensure the belt is completely in the pulley grooves. If necessary, refer to the photo you took after removing the mower deck from the lawn tractor.


On some models you will need to use your long handled flat blade screwdriver to hold the tensioner in place while you tighten the tensioner bolt.

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