Vauxhall VIVARO Owner's Manual page 114

110 Dropside body
To lower the sideboard:
Release both sideboard levers by pulling
the lever outwards.
Pull the lever down until it contacts the
body and lower the sideboard carefully.
To lower the tailboard:
Release both tailboard levers.
Lower the tailboard carefully.
To raise:
Raise the sideboard or tailboard and push
firmly against the body. Push the lever up
into its recess until an audible click is heard.
Check the sideboard or the tailboard is
secure.