A leakage arresting system comprising a novel gas arrestor for installation on an interrupted pintle shaft in a pintle-type valve, such as an exhaust gas recirculation valve for an internal combustion engine, for preventing leakage of gas and moisture along the pintle shaft into the actuator, to prevent corrosion and failure of the actuator. The system comprises two elements: a pintle shaft which is interrupted outside the actuator, and a positive vapor block in the form of a cup-shaped arrestor disposed across the pintle interruption. The invention is applicable to both unbalanced and force-balanced valves.