A method to disassemble a mast assembly having a substructure including a first and second section, a first and a second cylinder, and a lower mast section. The method includes the steps of disengaging a pair of front mast legs of the lower mast section from a pair of front leg supports. The pair of front leg supports are moved from an operational to a transport position. The lower mast section is lowered from a vertical to a horizontal position by retracting the first cylinder and the second cylinder. A mast center spreader is thereafter removed from the lower mast section. A center drill floor section is removed from between the first substructure section and the second substructure section so that a combination of the first substructure section, the first cylinder and a portion of the lower mast and a combination of the second substructure section, the second cylinder and a portion of the lower mast may be transported.