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