Date:         Mon, 25 Nov 2002 12:20:52 -0800
Reply-To:     Mark Keller <kelphoto@HIGHSPEEDPLUS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mark Keller <kelphoto@HIGHSPEEDPLUS.COM>
Subject:      emergency brakes
Comments: To: drillock@EARTHLINK.NET
Content-Type: text/plain; charset=us-ascii; format=flowed

Mark,

Normally, Rear brakes are self-adjusting.  The Bently does not say they
are or are not.  Bentley's service interval section in the back of the
book mentions checking brake fluid level and checking brake material
thickness, it does not say to adjust rear brakes but so I assume they
are self-adjusting, even though this little trick on happens when the
vehicle is moving backwards before the brakes are applied, to generate
the force so that opposite rotation applied to  brake shoes mechanical
adjusting arm moves the adjuster star wheel which moves it one click per
iteration..  Because of this, I've seen cars that people just don't back
up enough to keep the rear brakes properly adjusted.  So under  some
operations the rear brakes may indeed need a manual adjustment from time
to time. And  it seems that they require manual adjustment when I put
new shoes on.  So brakes will self adjust and should not ordinarly  pose
an issue of the emergency brake arm contacting another metal object and
limiting the amount of emergency braking effort applied through the
handbrake.

So, I'll  take a look at my rear brakes again, they were adjusted
manually, but  there may be a issue of mechanical interferance, I
certainly can see why from the post, and were talking about several
hundred different vans, but I wasn't aware that mechanics or home
mechanics would regularly adjust the parking brake on vehicles with self
adjusting brakes and inadvertly be exceeding the range of free movenent
of the emergency brake arm whithn the drum, and thereby causeing a
mechanincal interferance rather than applying the force to the shoes and
drum.

The variables I wrote about are recognized as affecting braking force on
drum braked applications and could be  well worth looking into since
this are normal wear  and replace issues.

I believe that both the adjusment sequence and the inspection and
correction if need be of  brake/ drum fitment as well as a softer brake
material compostion should be included together in order to get at the
issue of why a particualr van's emergency brakes don't hold the vehicle
as well another van.


Sincerely,

Mark Keller
91 Carat