Volvo S40 Owner's Manual page 151

06 Starting and driving
Detachable towbar
Removing the towball
– Insert the key and turn it clockwise to the
unlocked position.
06
150
– Push in the locking wheel (1) and turn it
anticlockwise (2) until you hear a click.
– Turn the locking wheel down fully, until it
comes to a stop. Hold it in this position
while pulling the towball rearward and
upward.
WARNING
Firmly secure the towbar's loose towball if it
is stored in the car's cargo area.