Brake fluid guide: when and why to change it
Brake fluid absorbs moisture over time — here's when to replace it.
Brake fluid is hygroscopic — it absorbs moisture from the air. Over time this reduces performance and increases the risk of boiling under hard braking. Rule of thumb: replace every 2 years or 40,000 km. Check your manual for the required grade (DOT 3, DOT 4, or DOT 5.1).