What am I looking For?

[hlava]

I've got a weird sound coming from the front driver side, maybe from the
wheel area. It might be happening on the other side, also, but I can hear
the front driver side because I have the window down.

It doesn't sound like a clicking noise, I don't notice it when I don't apply
the brakes, or at least it's so low I can't hear it w/o the load on the
wheel from the brakes. It's kind of like a whirring/shushshush sound when I
apply the brakes and is speed dependent.

I've pulled and looked at the calipers, rotor and pads... I thought the
calipers may be slipping, if that's possible. The rotor doesn't appear to be
warped, no uneven pad wear or scoring marks on the rotor.

My next thought is the axle, but everything looks clean and I get no extra
wiggle when I have the front in the air. And, the front drivers half shaft
has been replaced in the past by the previous owner.

It almost sounds, under harder load when braking, that the brakes are
"dragging" or grinding.

I'm a bit puzzled.

Thanks for your time,

Mark