Brakes Tell You When Something’s Wrong
If your brake pedal feels spongy, vibrates or needs to be pushed further than usual, or your vehicle pulls to the side when braking, or you hear squealing or grinding noises… It’s time to have your car serviced.
To prevent damage from moisture entering the braking system and to assure reliable performance, your brake fluid should be changed periodically.
Regular brake service is a prevention against rust and corrosion and will help avoid more expensive repairs in the long run. Even if your brakes seem to be working well, an inspection could reveal potential problems that can be solved before any costly damages occur.
Generally braking systems work with brake fluid and hoses connecting the master cylinder to each wheel's brake. Pushing the pedal creates hydraulic pressure that sends fluid from the master cylinder through the hoses to the brakes.
Source: Brakes - NAPA AUTOPRO