Abstract: A clamp assembly for an injection molding machine includes a clamp piston slidable within a housing among a clamping position, a mold break position, and a meshing position disposed axially intermediate the clamping and the mold break positions. A clamp chamber urges the clamp piston towards the clamping position when pressurized, and a return device urges the clamp piston from the clamping position to the meshing position when pressure in the clamp chamber is relieved. At least one mold break actuator is coupled to a mold break engagement surface disposed within the housing. The mold break actuator is adjustable to accommodate retraction of mold break surface when the clamp piston moves to the clamping position, and to forcefully push the mold break surface forward against the clamp piston when moving the clamp piston to the mold break position.