How to Check the Brake Fluid Level?

[StBrady]

Braking is a critical safety concern for car owners, so it should never be taken lightly. Brake fluid is one of the key components. Below is a simple method to help you determine whether the brake fluid you are using is of good quality. Pour a small amount of brake fluid into your palm and gently rub it with your fingers. If it is good-quality brake fluid, you will immediately feel warmth in your palm, and the more you rub, the more intense the warmth will become. If the brake fluid is fake or of poor quality, it will heat up very slowly. There are three types of brake fluid. For the safety of you and your family, always choose reliable and reputable manufacturers when purchasing brake fluid. The working pressure of brake fluid is generally 2MPa, and can reach as high as 4~5MPa. All liquids have the property of being incompressible. In a sealed container or a pipeline filled with liquid, when pressure is applied, the liquid quickly and evenly transmits the pressure to all parts of the liquid. Hydraulic braking operates based on this principle.

[McKaylee]

I usually wait for the car to cool down completely in the parking lot before opening the engine hood, then locate the round canister with the steering wheel icon. There are two marked lines on the transparent wall of the container—the fluid level should stay between MIN and MAX when the engine is cold. If it drops below MIN, you must immediately visit a mechanic to check for leaks in the system. Last week, my neighbor’s SUV suddenly had soft brakes due to brake fluid leakage—this is something you can’t afford to overlook. Remember never to check when the engine is hot right after turning it off, as high-temperature fluid may splash. Also, avoid letting dust fall into the opening, as it could affect braking performance.

[DelGenesis]

As someone who frequently drives long distances, I've developed a habit of checking fluids every Wednesday. After lifting the hood, I go straight to the brake fluid reservoir, which is usually connected to the master cylinder near the base of the windshield. Wiping off the dust from the reservoir wall with a finger reveals the fluid level, often at the two-thirds mark in new cars. If the fluid level drops more than 5mm in a month, it's likely due to severely worn brake pads or a leaking wheel cylinder. Last time my car's fluid level dropped abnormally, it turned out to be an aged seal in the left rear wheel cylinder, which I replaced in time to avoid brake failure. Pay extra attention during the rainy season—a rippled oil film at the bottom of the reservoir indicates the brake fluid has absorbed water and deteriorated.

[LaElliot]

Here's a 10-second check method: When the engine is cold, locate the white translucent reservoir labeled BRAKE FLUID in the engine bay. I usually press my phone's flashlight against the tank wall—the reflected light band of the fluid level should fall in the center of the grooved area. During my last service, the mechanic mentioned that for Japanese cars like mine, rapid brake fluid level drop often signals the brake pads are down to just 3mm. For older models, note that some metal reservoirs require unscrewing the cap to check the fluid level—handle this with caution.