What is the function of brake fluid, and why change it.
When you apply pressure to the brake paddle, the brake fluid transfers this force to the brake caliper pistons; and the piston pushes the brake pads onto the brake disc. Therefore, your car stops.
The ability for brake fluid to transfer force comes from its incompressible property. Unlike liquid, vapor is highly compressible. Hence, the existence of vapor along with the brake system brings negative effects to the hydraulic transfer of the force. In the worst case, it may result in brake failure.
Although brake fluid is subjected to very high temperature and has a very high boiling point. It degrades slowly over time, and the boiling point decreases as well. This is because of two reasons:
1. Repeatedly heating up (heat emitted from the friction between the brake pad and brake rotor) and cooling down.
2. Contamination, including moisture, shred, rubber, and rust, could cause corrosion to calipers, wheel cylinders, master cylinders, ABS control valves, etc.
When to change
It is recommended to have the brake fluid flushed every 50000km or 2 years, or whenever there is a leakage.
• Road test to value system performance.
• Perform system flush of worn-out brake fluid and any contaminants.
• Up to 1L of brake fluid.
• Comprehensive evaluation of your braking system.
• Detailed estimate for items requiring adjustment, repair or replacement