How to Replace a Drive Belt on a Craftsman Lawn Mower

The first step is to put on your gloves and place your craftsman lawn mower on flat ground like a garden shed or garage, as a sloped surface will make it challenging to work on it. Before commencing, ensure you turn off the ignition and remove the key. 
To avoid electrocution, remove the power cable and the spark plug. Tightly seal off the fuel tank to eliminate chances of fuel leaks. You can use a polythene bag to cover the fuel tank opening and then tighten the cap.

You will need to drain the gas and oil to be able to replace the drive belt without issues. You’ll need to tip the mower on its side.

 Using a brush, clean the dirt on the deck and the debris on the shaft. Cleaning not only makes your replacement task easy but also improves the overall lifespan of the mower.

To be able to access the drive belt for removal, you need to loosen the crankshaft pulley. To do this, use a socket wrench to turn the flywheel bolt clockwise. Turn the crankshaft pulley counterclockwise until you bring it out. At this point, free up and remove the old and worn-out belt. Remember to pay attention as you remove the drive belt as it may be under tension.

First, at this stage, lower the front wheels back to their initial position by removing the wooden block. Insert the new belt via the deck’s front while ensuring there is contact with the transmission pulley. Settle the belt on the transmission pulley by pulling the hood upwards, and once done, lower back the front hood. 
Then, lift the front wheels by pressing the rear handle and placing a block of wood under the deck. Using a socket wrench, tighten the belts by turning them in the counterclockwise direction. Reinstall the crankshaft pulley to its initial position by turning it in the clockwise direction. Then carefully attach the crankshaft pulley with the drive belt.

Using the screws, settle the crankshaft pulley with the blades. Using the socket wrench, tighten the attaching screws. Once the blade is in place, you can lower the front deck again by removing the block of wood.

Now, it’s time to test whether the drive belt replacement is successful. Unseal the fuel tank by removing the polythene sheet under the fuel tank cap. Reconnect the spark plug and the power cable to the battery. Start the craftsman mower and try to mow while monitoring its precision, cutting speed, and movement. 
Also, listen for any weird noises from the mower. If everything is working well, then you can go ahead to mow your lawn. However, if you hear squealing noises or notice something abnormal, you might need professional help.