How Many Liters of Brake Fluid Are Needed for a Car Brake Fluid Change?
3 Answers
Car brake fluid change requires only 1 liter. It is essential to replace it with brake fluid of the same grade as the original. The brake fluid grade can be found on the brake fluid cap. The function of brake fluid is to increase the hydraulic pressure when the brake pedal is pressed, allowing the master cylinder to push the fluid. This action causes the pistons in the four-wheel slave cylinders to extend under the sealing effect of the rubber cups, utilizing the lever principle to apply force on the brake discs and pads, achieving the braking effect. Brake fluid replacement is not solely based on time or mileage but also depends on the climate and humidity of the region where the vehicle is operated. In tropical regions, it should be changed annually or every 20,000 kilometers; in cold regions, every two years or 40,000 kilometers; and in temperate regions, every three years or 60,000 kilometers.
In my years of experience in car repair, replacing brake fluid typically requires 0.5 to 1 liter, depending on the vehicle model. For small cars or sedans, 0.5 liter is usually sufficient, while larger SUVs may need 0.8 liter or a full liter. Remember to thoroughly bleed out both the old fluid and any air from the new fluid during the process, otherwise the brakes may become spongy, compromising safety. This procedure requires a vacuum pump, and step-by-step operation is crucial. Additionally, brake fluid absorbs moisture over time, lowering its boiling point. If not replaced promptly, vapor lock can occur during hard braking, potentially leading to accidents. I recommend checking it every two years or after 20,000 kilometers, referring to the vehicle manual for precise quantities. For convenience, keeping a 1-liter bottle of brake fluid on hand is most reliable. Any excess shouldn't be wasted and can be recycled. In summary, this is a crucial part of routine maintenance that shouldn't be overlooked.
I've changed my brake fluid three times myself and found the usage to be around 0.5 liters with slight variations. Last time, I was working on a small family car and used 0.6 liters of new fluid, mainly because the entire brake line needed repeated flushing to ensure no residue remained. The operation isn't difficult but requires patience—first, loosen the bleeder screw on the brake caliper, then use a fluid gun to inject new fluid until the old fluid is completely expelled. Brake fluid is corrosive, so wearing gloves for protection is crucial. Why change it regularly? Aged fluid absorbs moisture, leading to degraded braking performance and significantly increased risks at high speeds. For regular car owners doing this at home, I recommend buying a 1-liter bottle to avoid running out. Don't cheap out on off-brand fluids; branded DOT4 or DOT5.1 fluids are more suitable. Always follow the operation guide carefully—safety first, no exceptions.
