24 March 2026
Are you looking to change your brake fluid but unsure which fluid you should use for your car? Learn what brake fluid is, how often it should be changed and which brake fluid you need for your vehicle with our helpful guide.
Brake fluid, also known as hydraulic fluid, is crucial for lubricating parts of your braking system and for transferring hydraulic pressure through the braking system. When the brake pedal is pressed down, the brake fluid applies hydraulic pressure to the brake callipers, which causes the brake pads to press against the brake discs to slow down your vehicle and bring it to a stop. Your braking system will be ineffective if you do not keep the brake fluid topped up or if you don't choose the correct brake fluid for your vehicle.
The amount of brake fluid a car needs is actually quite small compared to other fluids like engine oil, because it only fills the brake system rather than being consumed during use. Most passenger vehicles typically require around 0.5 to 1 litre of brake fluid to completely fill the system, but in normal situations you won’t need to add that much. If you’re just topping up, it’s usually only a small amount to bring the fluid level back up to the “MAX” line on the reservoir. However, if you’re performing a full brake fluid change or bleeding the brakes, you may need closer to a full litre to ensure all old fluid is flushed out. The exact amount can vary depending on the size and type of your vehicle, so it’s always best to check the owner’s manual for the manufacturer’s recommendation.
Typically, vehicle manufacturers recommend your car’s brake fluid be changed at least once every two years or every 24,000 miles. However, as recommendations can differ, check how often to change the brake fluid in your vehicle's handbook or book a free brake check at your local Setyres garage online. Following your car manufacturer's recommendations for changing or topping up brake fluid will help to maintain the quality and lifespan of your vehicle's brakes.
There are many brands and types of brake fluid available. However, these can be classified as follows:
The most commonly used brake fluids are DOT3 and DOT4, although DOT 5.1 is also used in some modern vehicles and high-performance applications due to its higher boiling point and improved performance under extreme conditions – you can find out which brake fluid you need for your car by checking your vehicle handbook.
The DOT (Department of Transport) rating refers to the boiling point of the fluid. The higher the DOT rating, the higher the boiling point and performance quality of the brake fluid. High-performance sports cars, for instance, would require a higher DOT rating of brake fluid such as DOT 5.1, which offers similar compatibility to DOT 3 and DOT 4 but with enhanced performance.
No, you can’t just use any brake fluid brand without checking a few important things first. What really matters isn’t the brand name, but whether the fluid meets the correct specification (DOT rating) for your car. Brake fluids are made to standardised ratings like DOT 3, DOT 4, DOT 5, and DOT 5.1, and your vehicle is designed to work with a specific type. As long as the brand you choose meets the same DOT specification listed in your owner’s manual or on the reservoir cap, it is generally safe to use, even if it’s a different brand.
However, you should never use the wrong type of brake fluid, even if it’s from a well-known brand. Different types have different chemical compositions, and using the wrong one can damage seals, reduce braking performance, or even cause brake failure. For example, silicone-based DOT 5 fluid is not compatible with the more common glycol-based fluids like DOT 3, DOT 4 or DOT 5.1, which is also glycol-based and compatible with DOT 3 and DOT 4 systems (unless otherwise specified by the manufacturer) and they should never be mixed.
In short, you can use different brands, but only if they match the exact specification your car requires. Always check your owner’s manual first when it comes to brakes, using the correct fluid is far more important than the brand name.
Technically, while some brake fluids can be interchangeable, we would advise referring to your vehicle handbook's recommendations. Choosing a different DOT rating can be dangerous as the brakes can be damaged, and your vehicle's performance can be detrimentally affected.
Topping up your car’s braking system with the wrong brake fluid can affect the integrity and responsiveness of your brakes. You should check the vehicle handbook to ensure you choose the correct brake fluid. Need to book a free brake check?
If you’d like to book a free brake check today, visit our brakes page. Alternatively, if you need advice about your brakes or want to book a repair, check our vouchers to save money and locate your nearest Setyres branch, or contact a member of our team on your local dedicated branch page.