Ford Vacuum Check Valve Direction Diagram - Airflow & Black Vacuum Side

This document is Figure 125, titled 'Vacuum Check Valve,' from an automotive reference manual. It is a line-drawing schematic showing three different styles of vacuum check valves used in engine vacuum/emissions systems. An arrow at the top labeled 'DIRECTION OF FREE AIRFLOW' indicates the orientation in which air can pass freely through each valve. A callout pointing to one end of each valve identifies the 'VACUUM SIDE: BLACK,' telling the reader that the black-colored side of the valve is the side that faces the vacuum source. The illustration reference code A6067-D appears in the lower right corner. From this figure, a reader can learn how to correctly orient a vacuum check valve when installing or replacing it: the black side goes toward the vacuum source, and free airflow moves in the direction of the arrow shown. The drawing depicts three common body shapes (a barrel/disc style and two cone/tapered styles) so the identification applies regardless of which physical variant is fitted to the vehicle. The scan was uploaded alongside 1990 Ford Bronco and Mustang emissions diagrams, suggesting it is used for servicing those vehicles' vacuum systems.