What was found
PILOT REPORTED RIGHT VACUUM PUMP WARNING LIGHT WAS ON. DURING TROUBLESHOOTING, DISCONNECTED HOSE FROM RIGHT SIDE OF CHECK VALVE MANIFOLD TO CONNECT TEST KIT AND DISCOVERED TWO MISSING RIVETS, TWO RIVETS ABOUT TO FALL OUT AND TWO LOOSE RIVETS ALL ON THE RIGHT SIDE OF CHECK VALVE ALLOWING VACUUM AIR TO LEK OUT BETWEEN, THE VALVE DIAPHRAM. PROBABLE CAUSE IS VIBRATION FROM ENGINE , ACTING ON HOSE CONNECTED THIS END, CANNOT SEE AT THIS TIME, ANY OTHER ROUTING OF HOSE.