A vacuum regulator valve unit has a valve body and a coil assembly that define a chamber. The valve body has an air inlet passage opening into the chamber. A washer overlies the valve body within the chamber and has an air inlet port aligned with the passage and a valve seat surrounding the port. The coil assembly supports a shaft projecting into the chamber. A valve member is mounted loosely on the shaft within the chamber and slides on the shaft into and out of engagement with the valve seat in response to energization and deenergization of the coil. The valve body has a peripheral annular ledge that cambers the washer to assure full engagement of the washer with the valve body at the perimeter of the port. The shaft has an undercut taper that articulates the valve member to allow the valve member to align with the valve set and thereby assure full engagement of the valve member with the valve seat.