Ah yes - Dennis is correct here.  Working in the auto parts industry I've
seen this many times.  Even if the surface is still smooth and true, there
can be pad material leftover from the offending ones glazed on to the
rotor.   I would not install pads without either replacing the rotors or
prepping the surface first.   The only time I ever did a pad slap was while
travelling in Germany as a quick fix to get me on my way. The new pads need
a good surface for proper bedding. Generally the more aggressive a pad is
the more tendency it will have for the occasional squeak.   Low dust / no
noise pads = lower performance.  For some this is an acceptable trade off.
I always stick to an OE quality pad and don't really care about a bit of
brake noise.   I want my bus to stop as good as possible.

Jason

On Sun, May 10, 2015 at 10:57 AM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> What is the condition of the rotors? New or at least re-surfaced? Most
> brake
> squeals are the result of friction irregularities between the rotor and
> pads. This can be from the rotors not turning true or the surface being
> glazed or worn unevenly or having surface irregularities. One thing with
> disc brakes is that the outer diameter of the rotor is actually traveling
> faster than the center. The pads design and mounting has to take this. The
> sequel is the pads oscillating and chattering. Silencing shims can be the
> best defense. There are now also piston cushions available to fit between
> the piston and inside pad.
>
> If the rotors were not replaced or at resurfaced I would begin there.
> Remember the where limit is 13mm for these. If near or below that thickness
> time for replacement.
>
> Dennis
>
>