Changing brake fluid, general
WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
When should the fluid be changed?
It is recommended that brake fluid is changed every other year. In the event of heavy and frequent braking, such as mountain driving or in tropical climates with high humidity, the brake fluid must be changed every year.
Why change?
The brake fluid is hydroscopic, i. e. the fluid absorbs water molecules from the air. This occurs via the brake hoses and the brake fluid reservoir, which is made of rubber and plastic, and is not impervious to water molecules.
High water content lowers the brake fluid's boiling point greatly, and causes corrosion in the brake system.
This damages the brake system, and reduces the braking effect.
NOTE:
Use only Volvo Genuine brake fluid (minimum) DOT 4+. Never reuse brake fluid. Always keep brake fluid in its original packaging and well sealed.