How to tell your brake fluid needs changing

Brake fluid is a special hydraulic fluid composed of synthetic additives, corrosion inhibitors and used to operate brake systems. Brake fluid is used in the brake systems of motor vehicles to build pressure when applying brakes. You may need to use a periodic (time based) maintenance schedule or inspection of brake fluid colour and level in the brake fluid reservoir.


When you apply your brakes they use friction to stop the wheels. This process generates a lot of heat. Brake fluid must have a recommended glycol base with special qualities such as a wide temperature range, high boiling point with low volatility, correct viscosity, resistance to corrosion and ageing with good compatibility with sealing components of your brake system.


Did you know that for every 10,000 – 15,000 kilometres an average driver will apply the brake pedal 75,000 times? It is recommended that you renew your car’s brake fluid every 40,000 – 50,000 kilometres. Brake fluid by design tends to attract moisture from the atmosphere through rubber seals and openings. Moisture causes corrosion.


Although brake fluid is designed to withstand corrosion overtime the corrosion inhibitors deteriorate due to age and the intense heat. This will also reduce the boiling point (ability to withstand heat), lower the volatility as well as affect the viscosity (thickness and ability to flow freely).

 You should therefore use the age factor to periodically renew your brake fluid. In the absence of a vehicle’s service history carry out a precautionary brake fluid service. In the event that your brake fluid has changed colour to dark brown act even faster to replace it. You can inspect the brake fluid level and colour using the reservoir attached to the brake master cylinder.

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