Buy OEM Volvo Part # 31323210. Coil Spring (Rear). REAR SPRING. Variant code: 780Z. Suspension Coil Spring Your coil springs are not especially prone to failure, but

Spring, Helical Spring and Torsion Spring.
A Coil Spring is a spiral or helix of metal wire that is commonly made up of steel and is used in many automotive suspension systems. Coil Springs are mechanical devices that accept a weight or force from one object to absorb the energy and to prevent the surface from being damaged.

Fits S60, S60 Cross Country, S60 Inscription, V60, V60 Cross Country, XC60, XC70

Variant code: 780Z.
Suspension Coil Spring
Your coil springs are not especially prone to failure, but if they have been cut, clamped, or heated to have the vehicle lowered, your Volvo might benefit from replacing the strut springs. Excessive rust can make the springs more prone to failure. Contact your local Volvo service department to have your suspension system evaluated.