Why does the brake become harder after changing the brake fluid?

[IsaacRose]

After changing the brake fluid, the brake becomes harder for the following reasons: Normal phenomenon: It is actually a very normal phenomenon for the brake to feel too hard right after changing the brake fluid, as it requires a period of time for the new brake fluid to break in. Solution: Simply lightly press the brake more frequently while driving to accelerate the break-in process of the brake fluid, and the original pedal feel will soon be restored. However, the quality of the brake fluid also plays a role, so it is best to purchase from reputable sources to avoid unnecessary expenses. But if the pedal feel becomes significantly softer, it is likely due to errors during the replacement process, causing air to enter the brake lines, which needs to be promptly bled out.