Re: Part/repair advice wanted

[Steve Bradley <scscomp@mindspring.com>]

Melissa & Jim wrote:

> On 30 Nov 97, Ginger D.&Peter P. wrote:
>
> >       Jim mentioned that cheap disk brake pads don't tend to squeel.  Where
> > do I get cheap T3 pads (Repco I think)?  Does NAPA actually sell T3
> > parts?
>
> Probably.  Our pads actually fit a number of cars, so all they have
> to do is look up and find out which part of their stock we use.
>

This note on squeeling disc brakes. A local auto repair radio talk show in
Atlanta has a mechanic named Sam Memmolo on it. He says the reason disc brakes
squeek is that the rotors have probably been turned using a directional cutting
tool (the kind on just about every brake lathe in mechanic shops).

These directional cutting marks cause the pad to "dance" on the surface of the
rotor when pressure is applied, thus causing them to vibrate against the pad
holders and make a noise. The cutting marks can also cause new pads to
prematurely fail, depending on the type of pads used.

He says the original cut on the OEM rotors is done using a helical cutting tool (
makes curved cutting marks across the face of the rotor instead of parallel to
the direction of rotation of the wheel).

He comments that you can smooth down these cutting marks by mounting the rotor,
spin it and sand it with 320 grit emery cloth, moving the paper back and forth
from the hub to the outer rim of the rotor to remove the directional cutting
marks of the brake lathe. He says the smoother the surface, the less the squeel.

Steve B.