Brake pedal while stopping at low speeds, it makes the spring-kind noise

Hello. When I release slowly from the brake pedal while stopping at low speeds, it makes the spring-kind noise from the pedal. It is somewhat faint but it comes on and off. The dealership thought the noise was from brake switch but even after replacing that, the noise is still there. The sound is kind of different from clanking or squealing sound but so I checked it out I need front brakes please help me do the job.