Think about how often you depress the brake pedal on your daily commute to slow down. It’s repetitious, and that’s why it’s critical that your vehicle’s braking system is in tip-top condition. Things like brake pads and discs have visual indications of wear and tear but brake fluid however often goes unnoticed and therefore unchanged.
Ensuring your brake fluid is topped up to the mark on the side of the reservoir is a good start, but it’s also the condition of your brake fluid which can affect your braking performance. If you need your brake system checked, make an appointment with NRMA mobile mechanics where we can inspect your vehicle's braking system and provide advice on what is required to ensure your brakes are in top condition. We can carry out a brake fluid system flush and replace brake pads and disc rotors if required.
Brake fluids are hygroscopic, what does this mean?
Most brake fluids such as DOT 3 and DOT 4 are hygroscopic, meaning they will absorb moisture when exposed to air. The main enemy of brake fluid is moisture and this can be absorbed through brake lines or the brake fluid reservoir even when the vehicle is not driven. This is the normal process of the fluid’s life cycle but it is exacerbated in more humid conditions and climates.
After a year in service your brake fluid will absorb approximately 2% of moisture. This decreases the boiling point of your brake fluid and heightens the risk of a brake failure.
Note: Make sure you use the correct brake fluid specification as per the vehicle manufacturer’s manual.
How a low boiling point can put you and your family at risk
When driving your vehicle, your brake pads can reach extremely high temperatures and this heat is then passed onto the brake fluid which can raise the fluid temperature to over 200°C. When the fluid gets too hot, small air bubbles start to form as it begins to boil and because air is more compressible than fluid, the risk of a spongy brake pedal increases. If the fluid is repeatedly heated past its boiling point, eventually the brake pedal will travel all the way to the floor without providing much force on the brake pads, meaning you may struggle to pull up at intersections. This is called brake fade.