Install the piston in the brake caliper

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.

Fig 1: Applying Thin Layer Of New Brake Fluid To Cylinders, Piston And New Sealing Ring

Courtesy of VOLVO CARS OF NORTH AMERICA.

Blow the ducts clean using compressed air.

Apply a thin layer of new brake fluid to the cylinders, the piston and the new sealing ring.

Install:

the piston in the caliper. Carefully press the piston to the bottom
the dust boot in the groove on the piston. Check that everything is positioned correctly
the rubber sleeves in the caliper for the locating pins.