Topping off your car’s brake fluid anytime may not be ideal. The reason is that overfilled brake fluid reservoir may do more harm than good. So, if you have a brake fluid level at the minimum line or above it, there’s no point topping it off. Conversely, if the fluid level is below the minimum line, ensure to refill as soon as possible. However, the content must not exceed the maximum line that is designed to help you gauge the fluid input.