The rear brakes on a Vanagon do a lot to help stop the vehicle. The 2" wide by 10" diameter offers a lot of surface area. Having the rear brakes working properly and using a good friction material makes a lot of difference. The main reason that most of think the brakes suck is because we can't get good friction material back there. From the factory the rear linings were a semi-metallic similar to what you find on some front disc pads. They had "bite". 

I tried getting a set of these some time back and they were not available for the Vanagon. Don't know if that was just a stock issue back then. 

FWIW the Go-Westy shoes fit without needing to shim out the lower shoes mounts. There does not appear to be anything special about the lining material. 
Auto-Zone carries new shoes for a really good price. They will need 3-4mm shims on the bottom, more if the drums are worn. The lining on this seems to work well after they get seated. I am still searching for a good shoe for the Vanagon. I used the dealer stuff until it became NLA.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Jim Felder
Sent: Monday, October 6, 2014 2:06 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Porterfield R4-S Rear Brake Shoes

They would have to be some mighty good shoes to show a noticeable improvement on the rear brakes.

Jim

On Mon, Oct 6, 2014 at 12:59 PM, Neil N <musomuso@gmail.com> wrote:

> Hi all.
>
> For various reasons, am considering upgrading rear brakes to these:
>
> http://porterfield-brakes.com/images/portstrt2008_11_06_02_45_30.pdf
>
> If anyone is running these, did you find a marked increase in braking 
> performance?
>
> I'll email porterfield but does anyone know it the lining on these is 
> as thick as the OEM dealership shoes?
>
> Thanks
>
> Neil.
>
> --
> Neil n
>
> Blog: tubaneil.blogspot.ca
>
> '88 Westy http://tinyurl.com/c8rlw6p
>
> '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
>
> Vanagon VAG *Gas* inline-VR Engine Swap Group:
>
> http://tinyurl.com/d7gd5ej
>