The answer to this is dependent on whether the damper is a compression or extension damper; each having specific orientations and should be mounted as follow:
Extension Dampers
Extension dampers should be mounted ‘rod down’ to ensure consistent damping throughout the stroke.
Mounting the damper ‘rod up’ will result in little or no damping.
Compression Dampers
Compression dampers should be mounted ‘rod up’ to ensure consistent damping throughout the stroke.
Mounting the damper ‘rod down’ will result in little to no damping.
Lubrication of the main seal is not a problem due to the high volume of oil used in the damper.