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Re: Silicone Brake Fluid vs DOT3 or 4

To: Chris Lillja <Chris_Lillja@pupress.princeton.edu>
Subject: Re: Silicone Brake Fluid vs DOT3 or 4
From: "M. Secrest" <msecrest@erols.com>
Date: Mon, 01 Feb 1999 16:43:47 -0500
Cc: "Michael L. Coop" <mcoop@amfam.com>, triumphs@autox.team.net
Organization: Up With Everything
References: <199902011452.JAA05159@mail.pupress.princeton.edu>
Chris Lillja wrote:
> 
> Michael, this topic always starts major controvercy.
> 
> The bottom line seems to be:
> 
> Both types of fluid work very, very well, especially in properly maintained
> brake system in a street driven car.
> 
> Dot 3 or 4 is inexpensive, a bit easier to bleed, absorbs water, and
> is a highly effective paint stripper.
> 
> Dot 5 is expensive, a little harder to bleed, does not absorb water, and is
> harmless to paint.
> 
> In my TR4A, which has decent paint, I use silicone. Which is a good thing,
> because occasionally a drop gets on the painted surfaces. It doesn't seem to 
>be
> that hard to bleed this simple brake system and the pedal is very firm -
> especially since I installed braided stainless lines.
> 
> All my other vehicles use regular Castrol LMA Dot 4. Which also seems to work
> great. I'm SUPER careful not to get any fluid on anything.
> 
> If you're the kind of guy who can pull a brake or clutch master cylinder
> without getting any brake fluid on anything, you're a better man than me. I
> salute you.
> 
> These fliuds DO NOT MIX. When mixed, even in tiny residual amounts left in a
> drained brake system, they turn into an acidic, seal eating, metal corroding,
> mess. If a system is going to be converted from DOT 4 to DOT 5 it really 
>should
> be totally cleaned out, every single inch of hose pipe and every singe
> component.

I'll agree absolutely with everything Chris has said.  However, I have 
noticed
that the price of DOT 5 has been coming down as it becomes more readily
available -- not that it's expensive to begin with -- and even the 
small auto parts stores are beginning to carry it.  I've also not
heard that a mixture of DOT 4 and 5 creates a terminally caustic
chemical -- and the manufacturer of at least one version recommends
a simple flush-out-old-fluid-with-DOT 5 approach, which I did a year
ago on my GT6 with no problems so far.  

--
Martin Secrest
73 GT6
72 TR6

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