Recently replaced the rear brake pads on my 1997 RL 3.5. I had just purchased the car and the pads were very worn. Shortly after replacing the pads, I started to hear a low pitched whine, almost a moan coming from the driver's rear wheel sometimes when I drive or when I accelerate from a stop. If I tap the the brakes, the noise will interrupt, but immediately return. I'm very concerned about this noise, but don't have any idea what it could be.

The hub and bearing is worn out and needs to be replaced. Get this done immediatly as it can cause an accident if it locks up completely.