[SEL] OT. Brake fluids

[Jim Hardman]

Rob, are these fluids really compressible?  No entrained gas bubblets?  Not 
many liquids really compress.  The whole world of hydraulics relies on near 
incompressibility and brake systems are a good example.

Perhaps I'm showing my ignorance, but I'm surprised that any gas-free 
liquids compress.

Elastomeric rubber does not compress unless there are air bubbles.  It 
deforms just fine, but squeeze it in here and it bulges out over there.  I 
thought gas-free liquids were the same way.

Jim in Vermont


----- Original Message ----- 
From: "Rob Skinner" <rob at rustyiron.com>
To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
Sent: Monday, May 18, 2009 6:14 PM
Subject: Re: [SEL] OT. Brake fluids


> Hi, Curt.  This is a subject over which I spend an abnormal amount of
> time pondering.  In a nutshell, you can mix DOT 3, DOT 4, and DOT 5.1
> without adverse effects to the system.  They are all glycol based.
>
> DOT 5.0 is silicone based, and you can not mix it with the others.
> 5.1 is several times more compressible than glycol based fluids and
> can allow a spongy feel.

> Rob Skinner
> Antique Stationary Engines
> La Habra, California
>
> rob at rustyiron.com
> www.rustyiron.com