# Adjustable brake proportioning valve for VW dual diagonal system



## GTIspirit (Dec 13, 2002)

What do people use as an adjustable brake proportioning valve for their VW's dual diagonal brake system? For the exact reasons that *Racer_X* stated here http://forums.vwvortex.com/zerothread?id=1433567 I won't use a single prop valve like Summit sells here http://store.summitracing.com/...h.asp for both rear brakes. So how do people adjust rear brake bias, if their VW is not equipped with a factory height sensing proportioning valve on the rear axle, and they want to maintain the independent circuits but don't want to have to adjust two valves side by side?
I've been thinking of using a factory height sensing proportioning valve hard mounted, pictured here again http://forums.vwvortex.com/zerothread?id=1433567, but I'm not quite sure if I fully understand the theory of how these things work with the spring pressure on the arm.


----------



## GTIspirit (Dec 13, 2002)

*Re: Adjustable brake proportioning valve for VW dual diagonal system (*56k warning)*

Hmmm, no thoughts? Let me link the pictures for views and a better picture of what I'm asking.








_Image from Summit Racing website_
This is your typical single inlet and outlet brake proportioning valve. This won't work too well on a VW brake system with individual lines running to the rear and a dual diagonal brake system.
I can't find any dual inlet/dual outlet brake proportioning valves so a single knob adjusts both rear brakes. But I'd rather than use two separate ones like the Summit Racing style. Hence I've been thinking of adapting a VW load sensing proportioning valve for a fixed adjustment application (adjustable kneepoint, but not self-adjusting as in the rear axle location).








_Courtesy of Carmadillo, who has these brake pressure regulators at a really good price, just a hair more than a single aftermarket prop valve. _
Problem is, I understand in theory how this VW prop valve works, but not the intimate working details, so I'm not sure how to adapt it to a fixed application.
So how else do people install an adjustable brake proportioning valve on their rear brakes?


----------



## Racer_X (Jul 14, 2002)

Your two basic choices are:
* Use two of the knob type adjustable valves. 
* Use the VW load sensing regulator. 
If you can fit the load sensing regulator to your suspension, that's the best choice. If you want to turn the VW load sensing regulator into an dual channel adjustable prop valve, there's a way to do that. I don't share too much info about that valve on public forums. If you want more information, send me an email and tell me how you think it works. I can confirm if you are on the right track, or, if you promise not to publish the information I'll be happy to help out and share some information.


----------



## wjbski (Feb 1, 2003)

*Re: (Racer_X)*


_Quote, originally posted by *Racer_X* »_ I don't share too much info about that valve on public forums. If you want more information, send me an email and tell me how you think it works. I can confirm if you are on the right track, 

great idea. These valves can be tweeked enough to really waken up the front to rear bias, but it takes time and effort to do it right.


----------



## Stewz-GTI (Feb 16, 1999)

I would use two and go with these Wilwood adjustable ones:


----------

