How to Level a Deck on a John Deere X300
Park the lawn mower safely on a level surface, set the parking brake and remove the key from the ignition switch. Inflate the tires if needed to the correct pressure (correct PSI is listed on the outside of the tire). Turn the mower adjustment knob under the operator seat to the 2.75 position. Press the mower lift pedal on the left side of the fender deck. Push down on the mower release latch on the dashboard and release the pedal to lower the deck.
Remove the mower deck level gauge stored in the middle of the mower adjustment knob. Lay the gauge under the lip, on the left side of the mower deck. The gauge should just slide under. If not, adjust the nut located just above the deck hanger at the rear of the tractor, using the wrench. Turn the nut clockwise to raise the mower and counterclockwise to lower until the gauge just slips under the rim of the deck. Repeat this step for the right side of the mower.
Slide the gauge up to the bracket at the front of the mower deck, the roller gauge wheel is bolted to this bracket. Loosen the two nuts equally at the rear of the draft rod assembly that connects the front of the mower deck to the frame. Adjust the two nuts at the front of the draft rod assembly; turn the adjustment nuts each equally, turn clockwise to raise the deck and counterclockwise to lower the deck, until the gauge just slides under the bracket.
Return the gauge to the storage position in the mower level knob.