Date:         Thu, 5 Feb 2004 02:49:16 EST
Reply-To:     THX0001@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         George Goff <THX0001@AOL.COM>
Subject:      Re: Metalic brakes / Brake Squeal
Content-Type: text/plain; charset="US-ASCII"

In a message dated 2/2/04 7:50:29 PM, dhaynes@OPTONLINE.NET writes:

<< Brake squealing is not actually
caused by the pads and rotor rubbing but the movement of the pads in the
caliper housing or in the case of drum brakes, the shoe rubbing on the
backing plate. Better brake pads will now often have a silencer shim
built in. If not, replace it. Also, brake silencing goo will help
applied to the back of the outer pad. Hi temp. caliper grease should be
used where the pad backing plate sits in the carrier. >>

Regarding disc brakes:
While it is possible for a caliper to be misaligned because of poor repair
work, damage or as the result of faulty manufacturing, which can cause the
brakes to squeal until enough pressure is applied to force the caliper into
alignment, a frequent cause of brake squeal is that the rotor is not being clamped by
equal but opposite forces on both of its faces.  If the brake system has been
neglected, the simple act of retracting the caliper pistons to install fresh
pads can cause a piston to bind to one degree or another.  Whenever the
pistons are retracted for pad
replacement, they are forced into a portion of the caliper bore which has
become a reservoir for all the crap in the old brake fluid.  Whatever is in there
can interfere with the sure and smooth movement of the piston.

Applying "brake silencing goo" is at best a Band-Aid which only dampens the
vibration and might mask a serious mechanical defect.  I once had a 70 mph
get-off right after a mechanic thought that, instead of changing out the caliper,
"goo" was the cure for the squealing brakes of my new bike.  Once the
dealership paid my attorney's tab with a little left over for me, they saw the light.

Grease should never be applied to the pad seats of the caliper; just clean
the seats thoroughly.

George