A flexible mower deck includes a center deck with a plurality of rotary cutting blades rotated by a belt engaging a driven pulley for each blade. A first wing deck and a second wing deck are pivotably attached to a first end and a second end of the center deck. Each of the wing decks are pivotable between a lowered mowing position and a raised transport position. A height of cut mechanism on each of the first and second wing decks raises and lowers the wing deck and includes a four bar caster wheel level mechanism holding a caster wheel sleeve in front of the wing deck in vertical alignment at any height of cut.