How to Replace a Deck Belt on a John Deere L100

Raise the front of the mower onto vehicle ramps if available. Lift the mower with a jack in lieu of ramps. Place jack stands underneath the front frame, on either side of the engine housing.

Lower the deck to the lowest setting, using the deck elevation handle. Place a folded towel or rag beneath the front lip of the mower deck. Remove the linkage retainer from the front of the deck to the lift linkage, using a pair of pliers if it is connected by a cotter pin. Use a ratchet and socket, along with an open end wrench if the retainer is a bolt and nut combination. Allow the front of the deck to fall freely onto the rag. Do not place your fingers between the front of the deck and the ground.

Remove the pilot screw from the belt housing on top of the deck. Use a ratchet and socket to remove the housing screw which is on the left side of the mower. Remove the belt housing.

Move to the right side of the mower deck. Release the tension on the deck belt by rotating the deck tension device inward, using a ratchet and socket on the right side pulley bolt. Remove the belt from the pulley closest to you. Remove the mower drive belt from the mower.

Install the new mower belt around the left side pulley first. Lay the belt across the deck toward the right side and the front of the deck. Move to the right side of the mower. Reach beneath the motor, and attach the belt around the front of the engine pulley, and keep some tension on the belt with your hand. Pull the belt toward the right side deck pulley.

Insert your ratchet and socket back onto the right side pulley, and rotate the pulley inward. Loop the deck belt around the pulley. Release the pulley tension slowly. Do not place your fingers between the pulley and the belt when you have the tensioner assembly compressed.

Check that the belt is centered on all three pulleys. Make adjustments as needed, using the ratchet and socket to release the tension and move the belt. Install the left deck guard housing back onto the mower deck. Tighten the pilot screw snug with a ratchet and socket. No torque is needed for the housing screw.

Lift the mower housing up with one arm, while you guide the linkage bolt or cotter pin back through the lift linkage and deck mounting. Insert the cotter pin through the linkage if equipped. Tighten the bolt and hardware firm, then back the bolt off 1/4-turn. Over-tightening the bolt and nut can cause the lift linkage to stick.

Lower the mower off of the vehicle ramps. Raise the mower off of the jack stands if that is what you used. Remove the jack stands from beneath the mower, then lower the mower front to the ground.