The noise is caused by the pads vibrating in the callipers.
If you did not get pads with shims you will get this noise.
You need to put anti squeal on the back of the brake pads. It comes in a can
and you spray a little on the back of each brake pad. Let it dry for a few
minutes and install the pads.

Hey all, I just did my first ever front brake job on my 97' Chevy
Malibu.  I got wearever rotors and bendix pads.  After I replaced them
and test drove it all seemed fine.  But after about 5 to 10 miles of
driveing i noticed a squealing noise when ever I was slowing down and
going around 10mph.  My breaking does not pull my car, and it seems to
be stoping just fine, but the nosie is ear pearcing.  Any ideas would
be of great use.  Thanks in advance.