Q: high pitched noise from the back on 2008 Ford Edge

Only upon acceleration one side lightly let off the gas it will go away if I push down on the pedal in the hype it's comes back I thought it was the belts replaced it that was not it noticed now it's coming from passenger side valve cover help

It may sound like the noise the rear wiper washer makes when it has not been used for awhile. It's not the normal high-pitched squeak when brakes need to be replaced. Sometimes the noise occurs while driving on uneven roads. It's sporadic, usually when the a/c is on; in all types of weather - sunny, rainy. Sometimes it appears after driving in rush-hour traffic for 30+ minutes, other times it appears in a few minutes when driving. Unfortunately I am unable to duplicate the noise for a mechanic to hear.

The noise is more of a "whine" - fairly quiet - and only when the car is actually moving forward while the brake is applied - noise is never heard while backing up with the brake applied. The frequency of the noise varies a bit but centers around 330 Hz. Noise is heard when braking at very low speeds (around 10 mph or less). Brake fluid level is normal. The noise can persist for a few seconds after foot is removed from the brake pedal. Heard the moment foot is applied to the brake pedal at low speed - even when braking is very gentle. Despite the noise, the car appears to brake normally but I am concerned of a potential problem.