Depressurize the Brake System
WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.
Close the cock on the pressure line. Open a nipple and close it again.
Checking for air in the brake system and for brake fluid leakage.
See Checking For Air In the Brake System And For Brake Fluid Leakage