UFO conversion options

Tom Mullane tmullane at snet.net
Thu Sep 26 22:00:03 EDT 2002

Message: 12
Date: Thu, 26 Sep 2002 15:35:44 -0400
From: C1J1Miller at aol.com
To: b.m.benz at prodigy.net (Bernie Benz)
Cc: 200q20v at audifans.com (200q20V mailing list)
Subject: Re: UFO conversion options


The rusted area is quickly polished; if you scrape at it, the center
ed area is very hard, and is not affected by the scraper; the outer
shiny m=
etal looking part flakes off exposing the true metal surface... perhaps
 not explaining what I've observed very well.


To elaborate:

It is like the surface of the rotor that contacts the pad is too hard
for rust to attack, so it attacks from the side, working its way behind
the .25 MM shiny thickness that contacts the pads.  It starts at the
inside and outside edges, then works toward the center of the ring.  As
it moves in, the contact surface flakes off like thick paint, leaving a
thinner and thinner strip in the center, like a road getting more and
more narrow.  In the area that no longer makes contact with the pad, the
rust is free to erode the rotor, unless the pads make contact with it
again as they wear.  It this happens, it can be pulsation city.

It doesn't take much erosion to reduce braking power drastically.

I have seen this mainly on rear discs that get light use.

I don't know if this is any clearer...


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