To begin with those boiling points are for "wet" fluid. In other words
saturated with water which would also mean it has been in use way too long.
Next, if you do get the fluid in the calipers near that hot your are also
already in trouble. I have seen the effects of bad or overheated brake fluid
causing loss of pedal. But seriously, the Dot 4 is higher performance
standard and the fluids are interchangeable. Dot 5 is an even higher
standard but it is usually silicon based instead of glycol so those cannot
be mixed. A quart is enough to flush the system even with the manual
transmissions with the clutch.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
JRodgers
Sent: Monday, December 30, 2013 11:12 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Break Fluid - DOT 3 vs DOT 3/4 Vs DOT 4

Dot 3  =  Boil point 280
Dot 3/4 = Boil Point 480
Dot 4  =  Boil Point 512

In looking at Brake Fluids tonight - "ol Red needs a refill - I found these
numbers.

The shelves were full of DOT 3 and 3/4 but only one little can of Dot 4
- And I wanted a 32 oz container at least.

Question: Would the Dot3/4 be safe for use in the Vanagon. I'm suspicious of
it - but there are copious amounts available. But the boil point is 32
degrees below the DOT 4.

Comments?

Thanks,

John