Had a complete front brake overhaul done last July of '06. Pads,
calipers, rotors, grease seals... all replaced on both sides.

For the last month or more I have had a rather high pitched warbling,
squealing sound coming from somewhere most noticeable during highway
driving where the speeds are 50mph or so. Sometimes there almost
continuous and sometimes not that bad. Usually takes 15 minutes of
driving to hear it.

Seems to be the front wheels as opposed to the rear. Pressing on the
brake pedal about 1/4 of the ways down and it goes away until I release
 it. This always works to stop it no matter how loud it gets.

At first I thought bearings. Garage (Goodyear) checked and said they
were fine. Someone told me check the brake pads. That there is some kind
of signal device that rubs the rotor if they are word out.

Took it back and they said pads "had plenty of life left". They said
they adjusted the rear brakes and it was now OK. $50 for that. They took
it for a ride and "heard nothing".

Sound was there as soon as I drove it the next day. Someone else told
me it sounds like glazing of the pads. If they were set too tight on the
install they will overheat whild driving and a glaze will result and
this squeal is the proof. Confirmed by pressing on the pedal to increase
pad to rotor pressure.

Any thoughts?