Date:         Thu, 9 Jun 2011 03:19:27 -0400
Reply-To:     Bill Glenn <idahobill@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Bill Glenn <idahobill@GMAIL.COM>
Subject:      Re: syncro - heads up on potential power steering line issue

>At 05:30 AM 6/8/2011, Frank Condelli wrote:
>>         Well, there's a novel idea !  A plastic covered cable
>> wearing through a metal line !  I don't think so.

and>

On Wed, 8 Jun 2011 10:01:01 -0400, David Beierl <dbeierl@ATTGLOBAL.NET>
wrote:

Frank, it's perfectly plausible.  Machinists use the principle for
>fine fitting/sizing of parts, using a tool called a lap which is made
>of a soft material (often copper) charged with abrasive.  Rust
>particles and road sand are perfectly valid abrasives for steel, and
>there could also be fretting corrosion occurring.

Not only is it plausible, I have experienced it.  About forty years ago I
installed adjustable air shocks on a small pick-up truck.  The shocks were
supplied with Schrader valves that I mounted on the rear bumper of the
truck, and small hard plastic lines of about 1/8" diameter were supplied to
connect the Schrader valves to the air shocks by way of compression
fittings on each end.  The shocks were of course adjusted by varying the
air pressure.  I remember not being impressed with the use of the plastic
lines, thinking them inferior.

Many years later I was pulling in to a parking space in front of a glass
storefront when I suddenly lost all braking.  I just barely managed to
engage the parking brake and stop before hitting the building.  Upon
investigating the loss of braking, I found that I had secured one of the
plastic lines of the air shocks in such a way that it crossed a steel brake
line and the plastic line had worn a groove in the steel line without there
being any sign of wear on the plastic, none at all.  The groove had finally
worn through the brake line, allowing the brake fluid to squirt out when
the brakes were applied.

This made quite an impression on me at the time because it seemed so
counter-intuitive, and because had the brakes failed in just about any
other circumstance, the consequences could have been grave.

Ever since I have been very careful to stay away from brake lines when
attaching anything to the underside of a vehicle.

Bill