Keeping your car’s fluids at the correct levels is a critical part of vehicle maintenance. These fluids ensure that your car ...

The vent allows air into the reservoir as the brake fluid level ... it's time to flush and fill brake fluid and replace the master cylinder gasket/seal. Check brake fluid level monthly and test ...

but like brake calipers, sometimes it can spring leaks or otherwise fail, and it must be rebuilt or replaced. The master cylinder is topped by the brake-fluid reservoir, which must be kept full.