Braking noise- sucking/ suction sound

[DoubleARanch]

I just noticed this today, I dont know if it just started doing it today or not but when i press the brakes there is a suction/ sucking kind of sound. It sounds like its coming from where the master cylinder is at. through the firewall. the only thing ive done today with it was drive to work and i put a new exhaust on and then drove to town and thats when i started hearing it.

thanks for any help, im new to this forum so i hope you guys can help me out some

[DoubleARanch]

I really need some help with this guys