susan@ccivax.UUCP (Susan Micciche) (10/21/85)
Thanks to all who responded to my squeaky "breaks" query. I am posting
a summary for the net because I've noticed at least one other similar
query. (I feel much less paranoid about the Dealer now.)
Susan Micciche
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The Scirocco probably has the classic German brake setup - disk
brakes in front, drum brakes in rear. If you take a close look at your front
wheels you will notice that the disk and pads are exposed. When you stop, the
pads clench the disk, and asbestos dust rubs off the pads and is released into
the air. Some of it settles on the wheels, which is the dirt you are seeing.
Drum brakes, unlike disks, have the pads inside the brake drum, so dust
isn't released onto the wheels.
I think new brakes squeaking is normal.
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Some brake squeak is normal on all cars with disk brakes. When the brake
pad touches the rotor as you apply the brakes, oscillations are set up in
the brake pads and rotors. If this reaches the resonant frequency of the
pads, you get noise, which is not harmful. The only harmful noise is that
of metal-to-metal contact, indicating a problem.
THE Dirt you mention is a normal product of all brake pads as they
normally wear. It is asbestos fiber that is worn off of the pads in
normal use. With drum type brakes, this stuff stays inside the drum,
swo you never see it. Disk brakes are exposed to the atmosphere, so
the dust gets on nearby parts such as the wheels. Don't worry too much
about the health related aspects of this asbestos dust. In order to
cause lung cancer, asbestos dust must be breathed in to the lungs (this is
why brake mechanics often wear dust masks), but when you wash your wheels,
the dust is bonded to the other dirt particles on the wheels, and is washed
into suspension in the wash water, or into a wash rag, and hence does not
become airborne.
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The squeaking is probably due to a small amout of oil or dirt on either the
rotors or the pads. It's an easy thing to do, but you might have to clean
them several times until you correct the squealing. There are special
cleaners for doing this.
The dirt is from the pads wearing (normally) as you brake. It's really
annoying, I know, but it's a fact of life with disc brakes. There is a
product out that claims to protect the wheels from this. You insert it
between the wheel and the rotor. I don't remember the name or manufacturer
off hand.