On my 1998 ML320 with 115,000 miles I am getting a clicking sound when braking at low speed. It seems to be coming from the front portion of the vehicle. It may also be there at higher speeds but if so is be masked by the additional noise.
I thought it was the plastic portion of the brake sensors grabbing. I have replaced the front rotor and pads with no difference in the noise.
You do not hear it with the windows up, but it is very noticable when they are down.
Has anyone else had this noise or have any idea what it might be?

1998 ML320 115,000 miles