Brake fluid is one of the most overlooked fluids in a car, yet it is the link between your foot and the brakes. Checking it takes two minutes and can catch a problem before it becomes dangerous.
Find and read the reservoir
The brake fluid reservoir is a small translucent tank near the back of the engine bay, usually on the driver side. It has MIN and MAX marks on the side. The level should sit between them. A level that has dropped can mean worn brake pads, since fluid moves out to the calipers as pads wear, or it can mean a leak.
Check the colour
Fresh brake fluid is clear to light gold. As it ages it absorbs moisture and turns dark brown. Dark fluid has a lower boiling point, which is exactly what you do not want under hard braking. If it looks like weak coffee, it is time for a change.
When to change it
Most manufacturers suggest a brake fluid flush every two to three years regardless of mileage, because the fluid absorbs water from the air over time. If your pedal feels soft or spongy, get the fluid and brakes checked sooner.
Frequently asked questions
Can I top up brake fluid myself?
You can top up with the correct DOT fluid for your car, but a dropping level usually points to worn pads or a leak, so find the cause rather than just refilling.
What happens if brake fluid is too low?
Air can enter the system and the pedal goes soft, which lengthens stopping distance. Do not drive far with a low level.
Keeping the whole braking system healthy matters. See our brake guides for pads and related parts.
