I have a 2006 TL base model. I have owned it since 2007. I do repairs myself. I have replaced brake pads and rotors a few times. I recently replaced the rotors, calipers, pads and hoses. The reason for replacing the calipers was I thought one of the pistons was sticking on the caliper. I had a constant sound at low speed on front left, without the brake pedal pushed of metal on metal or a squeal. The pads still had a lot of material left. I replaced everything and after a week of quiet the sound has returned. It's as if something is warped because the sound doesn't happen on full rotation only at one point in the tire rotation. I took everything apart twice now and greased pad shims. I rotated tires but the same. The tie rods and arms are solid. I am at a loss. The car on jack stands will make the noise and it sounds like it is coming from the brakes but am wondering if I looking in the wrong place. Could it be bearing? There is no roaring sound at highway speed so I wasn't looking at bearing issue. Any input would be appreciated.

 

Could there be something (debris / rust) on the hub grooves that is inhibiting a flat mating surface to the inside of the brake rotor causing a slight offset?

 

Sounds like a great suggestion. I up to looking at any idea. I try to throughly clean everything when servicing my vehicles. This is first time I've had a brake phantom that I can't figure out. Driving me nuts. Thanks for the advice!

 

Is your brake dust shield rubbing the rotor?