Brake spring noise?

I noticed about a week ago that my brakes make a "spring" type noise when I am slowing down. This usually happens when I am working on a complete stop. I did notice it also when stopping on a steep downhill. They don't make this noise consistently but enough that I have noticed. This sounds like it is coming directly from the brake pedal area. I checked to see if anything was loose or obviously out of place but found nothing.

Seems weird since I have never had any other vehicles do it. When I was driving big rigs I had one truck that literally had the brake pedal come loose. I had noticed something was off a few minutes prior but thought I would just check it at my next stop that was just a few miles down on some back roads. The brake pedal came loose as I tried to stop. Luckily I was in the middle of nowhere so I slowed down as much as I could and just used the parking brake to stop me. I tightened everything up and went back to the shop so the mechanic could double check things.

 

Forgot to mention that my truck has about 16,000 miles. No off-roading. Has driven through a bit of snow but nothing major. Just a few inches. Handled pretty well for a rear wheel drive.

 

Bring it to the dealership and bring this to their attention. It's a safety hazard.