Headlamp wiper arm

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.

Lift up the protective cover over the nut
Slacken off the nut a few turns. Leave the nut in place to protect the threads on the shaft journal
Remove the wiper arm from the shaft journal. Use a pipe wrench supported against the nut
Remove the nut and wiper arm
Disconnect the hose.