I've gone to the Castrol Dot 4 LMA (low moisture absorption)...
http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9012213&c
ontentId=7024043

Which by the way, they have upgraded to Full Synthetic.
Product Description
Provides Superior Lubrication for Anti-Lock Braking Systems (ABS).
Recommended for all U.S. and foreign vehicles with DOT 3 and DOT 4
requirements including GM Ford and Chrysler. - Exceeds DOT 3 and DOT 4
requirements. - Unique Low Moisture Activity (LMA) formulation provides
maximum protection against vapor lock brake failure. - Maintains a higher
boiling point than conventional brake fluids. - Superior protection against
chloride and zinc corrosion of braking system parts. - Ideally suited for
Audi BMW Jaguar Mercedes-Benz Porsche Saab Volkswagen Volvo Honda Acura and
many other brake systems. - Exceeds specifications SAE 1703 SAE 1704 ISO
4925 JIS K2233 and FMVSS No. 116 DOT 3 and DOT 4.

Still a spec to VW and haven't had ANY issues on a complete system redo for
our friend 90 Westy. (new MC, Front Calipers Rotors, Rear Cly etc.).

Jack

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mike Collum
Sent: Thursday, September 25, 2008 1:54 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Help-need advice and mechanic in Davis CA

In that you're from the frozen north ... where chemicals are put on the
roads in winter, I'm betting that a steel brake line rusted then blew
under pressure.  A mechanic here in Houlton, Maine says he's replaced
more steel brake lines in the last 3 years than in all the 15 years
prior.  They're using a different road treatment nowadays and thorough
brake line inspection is routine.

DOT4 brake fluid has a higher boiling point than DOT3 and is a better
choice.  The two are compatible.

Mike