Brake Pedal

Hello Everyone,
Question for anybody here before I have a get my head down into the footwell. When pressing the brake pedal on my car it gives off a hiss of air. Is this normal? Do I have a worn seal? It's especially noticeable when starting the car as no engine noise. Brakes work fine.
Thanks
 
Hello Everyone,
Question for anybody here before I have a get my head down into the footwell. When pressing the brake pedal on my car it gives off a hiss of air. Is this normal? Do I have a worn seal? It's especially noticeable when starting the car as no engine noise. Brakes work fine.
Thanks
More than likely normal servo noise, or the brake pedal would be rock hard