Everything you need to know about brake fluid
Every car needs a variety of fluids to run, with each of them serving a different and important purpose to ensure you get safely from A to B. Some of them we’re aware of: we use wiper fluid to clean the windscreen, and we fill our own tanks with petrol or diesel. But some of them we can’t see, like lubricant and engine oil. The star of today’s article, brake fluid, is one of the latter. But make no mistake: just because we don’t see it or hear about it as often doesn’t mean it’s less important. Today, we’re giving you the ins and outs of brake fluid: what it does, what maintenance is required, and how to tell if there’s a problem to ask your mechanic about.
What is brake fluid?
Brake fluid is one of the most important components of a safe and functioning engine. In fact, it’s what your brakes need to actually bring your car to a stop! Essentially, it turns force – of your foot on the pedal – into pressure – of brake pads onto wheels – to slow a vehicle down. Let us break that down a bit more. Brake fluid acts as a hydraulic fluid: when you press your brake pedal, you compress the cylinder holding the fluid. This compression forces the fluid out of the cylinder with force, amplifying the force of your foot on the pedal. The brake pads then squeeze the brake disc, which ultimately slows down your wheels and brings you to a stop.
Brake fluid maintenance
Brake fluid is hygroscopic, meaning it readily absorbs and retains moisture. This is perfect for a hydraulic braking system: it means any excess water created during the compression process won’t get the chance to stick around and rust your engine. But there is a limit to how much moisture it can absorb. Eventually, it will have exhausted its ability to bond to water molecules and will no longer function as intended, leaving the brakes at risk of malfunctioning. That’s why maintenance is so crucial. As a general rule, brake fluid should be replaced every 2-3 years depending on distance driven in that time.
