Place your mower on level ground and turn off the engine. Disconnect the spark plug with your wrench to prevent any accidental starts while you work on your Murray mower.
Set the parking brake and put the shift lever into the neutral position, which is marked with an “N.”
Undo the hex nut with your socket or wrench set by turning it clockwise. Keep turning it until the rear wheels don't move when you push your mower forward.
Release the parking brake and move your mower. If it doesn’t move, tighten the hex nut by turning it counterclockwise until the unit starts rolling.
Set the parking brake and push your mower. If the rear wheels remain in place, the drive brake has been correctly adjusted. If they do move, repeat steps 2 through 4 accordingly.