The L120 John Deere Mower, usually branded with Sabre/Scotts instead of John Deere, comes equipped with a dual-blade mower deck that measures between 42 and 48 inches depending on which deck John Deere installed. The process for leveling the mower deck is the same for many models including L100, L108, L110, L111, L118 and L130. When you level the deck, you will level it from left to right and from front to back.
Park the L120 on hard, stable, level ground.
Position a 2-by-4-inch piece of wood under the daft arm on the front of the mower deck. The daft arm is the metal bar that connects the deck to the mower. Position two other blocks of wood under the rear edge of the mower deck on both the right and left sides.
Lower the lift lever to drop the mower deck to its lowest position. The mower deck must rest on the wooden blocks. Grip the daft arm on the front of the mower deck and pull on it. The daft arm should allow some movement. This indicates that the daft arm has no tension holding it.
Locate the larger square black bracket on each side of the mower deck. The bracket holds the deck onto the bottom of the tractor. Loosen the leveling nut on each bracket with a 15mm wrench.
Raise the lift lever to its highest position and then lower the lift lever to the notch between the number one position and the number two position.
Push down on each of the black leveling brackets to take out any slack in the brackets.
Tighten the bolts loosened in step four to 40-foot lbs. of pressure with a torque wrench.
Turn the adjusting nut on the end of the daft arm with a wrench until it starts to lift the mower deck off the wooden blocks.
Raise the lift lever to the number three position and then turn the daft adjustment nut 1½ turns counterclockwise to set the correct downward pitch from front to back.