Check the brake disc
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.
Check brake disc friction surfaces.
If the brake disc displays signs of out-of-true, check its lateral run out. See Brake disc rear, calibrating .
Replace the brake disc if it displays signs of heavy wear, variable thickness or similar. To replace, see Brake disc rear, replacing .
NOTE:
Minimum recommended disc thickness/replacement limit = 10.0 mm. Minimum recommended disc thickness when installing new brake pads = 10.7 mm.