Date:         Sun, 10 Feb 2002 23:26:35 -0800
Reply-To:     Leon Korkin <korkwood@WSHOST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Leon Korkin <korkwood@WSHOST.NET>
Subject:      Re: A Snow Story (Whoa-vanagon!!!) and Lessons Learned
In-Reply-To:  <3f.4c1c1a3.296fb38d@aol.com>
Content-Type: text/plain; charset="ISO-8859-1"

Ben,
This is brake proportioning valve even though VW calls it brake pressure regulator.
You described its location correctly. The ordnary pressure regulator just reduces
pressure in outlet according to how it is adjusted.
BPV splits pressure in such way as the front brakes get almost 2 times the pressure
vs rear brakes to prevent locking up. It is preset by spring inside. It may vary somewhat
by inertia when driving.
Leon



1/10/02 7:18:37 PM, BenTbtstr8@aol.com wrote:

>In a message dated 1/10/02 6:18:41 PM Pacific Standard Time,
>korkwood@WSHOST.NET writes:
>
><< They all come with one. I cleaned few of them, they quit working after
> many years of use, accumulating lots of gunk and freeze. >>
>
>
>Leon,
>
>I believe you are talking about a brake pressure regulator. These are located
>just to the inside of the front frame rail on the passenger side on US spec
>vans. They are set to permit a fixed pressure tot he rear brakes so they do
>not lockup before the front.
>
>Chris is referring to a brake proportioning valve (BPV). To me that
>translates to an adjustable brake pressure regulator. Most such as the ones
>installed in VW Fox wagons, Golfs and Jettas have an arm attached to the rear
>axle. As you load more equipment in the rear the BPV changes the brake bias.
>Sorta like a primitive ABS.
>
>He may also be referring to a cockpit adjustable proportioning valve which
>you can adjust while in the driver's seat. You can change the braking
>characteristics of your vehicle easily that way.
>
>Installing one of these manually adjustable guys should be done with extreme
>caution as some of you who have seen me testing a rear brake conversion on
>one of my cars. If you permit too much pressure to go to the rear, they will
>lockup. Then you WILL experience what it's like to be a Hollywood stunt
>driver. Just make sure the spectators give you enough room when you do that
>180° turn.
>
>Hafta put one of these on my Vanagon once I get my rear brakes done.
>
>BenT
>to stop well
>
>