Purpose and Specifications

Castrol 15C540 React SRF Racing Brake Fluid is a premium DOT 4 fluid designed for high-performance braking in cars, motorcycles, and light trucks. It delivers exceptional heat resistance with a dry boiling point up to 325°C to prevent vapour lock during intense stops, and a wet boiling point of 270°C that holds up over time. Free of nitrites, this nitrite-free formula protects against corrosion while staying compatible with DOT 3 and DOT 4 systems. Comes in a 1-liter bottle for easy flushing and refill.

When to Use / Replace?

Use Castrol 15C540 in demanding conditions like racing, rallying, or heavy towing where brakes get extremely hot. Replace every 18 months for racing use to maintain peak vapour lock protection, or every 2 years for street driving per manufacturer guidelines. Shelf life is typically 3-5 years unopened if stored cool and dry. Flush the system completely before switching from standard fluids to unlock its full high-temp benefits.

• Ideal for disc and drum brakes (not mineral oil systems)
• Sustains performance longer than regular glycol fluids
• Miscible with DOT 3/4 but best used pure

FAQ

Is Castrol 15C540 safe for my daily driver? Yes, it's backward compatible with DOT 3/4 systems and excels in hot conditions without spongy pedal feel.

How often should I change it? Every 18 months for track use, or 2 years for road cars to avoid moisture buildup lowering boiling point.

What's the boiling point advantage? Dry up to 325°C, wet 270°C – stays firm when cheaper fluids boil and fade.