The top of the battery may get wet with rain water etc., because measures to protect the battery from water are not sufficient, and therefore, if the battery is a different type from the one installed at factory due to replacement, water may get into the inside of the battery depending on the shape of the top of the battery. If this occurs, the battery liquid level may rise and overflowed liquid may spatter onto the ABS hydraulic unit or the brake pipes, causing corrosion. At worst, brake fluid could leak, which results in reduced braking efficiency.