Brake Fluid: Why It Needs Changing and How Often

Brake fluid transmits the force from the brake pedal to the brakes. Most types absorb water from the air over time, lowering their boiling point and encouraging corrosion inside the brake system.

That is why manufacturers specify a regular change interval.

How often

Many manufacturers recommend changing brake fluid every two years, but intervals vary. Check your service schedule.

Why it matters

Under heavy braking, especially on long descents, moisture-contaminated fluid can boil, creating vapour bubbles and a spongy pedal. Moisture also corrodes internal components.

Signs of a problem

▸Soft or spongy brake pedal
▸Brake warning light
▸Fluid level dropping

Testing

Garages can test the fluid's moisture content or boiling point. Dark fluid can suggest it is old, but colour alone is not a reliable test.

Who should do it

Changing brake fluid involves bleeding the system to remove air. It is best done by a qualified technician unless you have the right tools and experience.

CAUTION: This is general automotive information, not professional mechanical advice. Always follow your vehicle manufacturer’s specifications and service schedule, and have brakes, steering, tyres, and other safety-critical systems inspected by a qualified mechanic.

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