Section 9 (Abs/Traction Control - Repair (E46)): Servicing
WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 2004 BMW M3, 2004 BMW 330xi, 2004 BMW 330i, 2004 BMW 330Ci, and 2004 BMW 325xi. However, it is still accessible from the selected car via links, so may be relevant.
Use brake fluid called for in owner's manual or stated on sticker on expansion tank. Brake fluid should be replaced every 2 years. See BLEEDING BRAKE SYSTEM . Over time, brake fluid will retain moisture from air and could cause brake fluid boiling point to drop from 464°F (240°C) to 320°F (160°C).