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Re: Silicone brake fluid

To: ingate@shiseis.com (Shane F. Ingate)
Subject: Re: Silicone brake fluid
From: "Chris Lillja" <Chris_Lillja@Pupress.Princeton.Edu>
Date: Tue, 12 Aug 1997 13:34:36 EST
Cc: triumphs@Autox.Team.Net
Organization: Princeton University Press
Shane-

I'm surprised at you. Ken's article said that Dot 5 most certainly
does NOT absorb water in any way. As a matter of fact, it is so
Impervious to water that any water in the system will puddle in a
certain spot -- possibly encouraging corrosion in that spot.
Baywatch aside, water and silicone do not mix ;>}. If the changeover
is done properly and completely, water can not get in to the system
at ALL.

And I quote:
"Advantages: 
          DOT5 doesn't eat paint. 
          DOT5 does not absorb water and may be useful where water
          absorption is a problem. DOT5 is compatible with all rubber
          formulations. (See more on this under disadvantages, below.)
Disadvantages: 
          DOT5 does NOT mix with DOT3 or DOT4. Most reported problems
          with DOT5 are probably due to some degree of mixing with
          other fluid types. The best way to convert to DOT5 is to
          totally rebuild the hydraulic system. Reports of DOT5
          causing premature failure of rubber brake parts were more
          common with early DOT5 formulations. This is thought to be
          due to improper addition of swelling agents and has been
          fixed in recent formulations. Since DOT5 does not absorb
          water, any moisture in the hydraulic system will "puddle" in
          one place. This can cause localized corrosion in the
          hydraulics. Careful bleeding is required to get all of the
          air out of the system. Small bubbles can form in the fluid
          that will form large bubbles over time. It may be necessary
          to do a series of bleeds. DOT5 is slightly compressible
          (giving a very slightly soft pedal), and has a lower boiling
          point than DOT4. DOT5 is about twice as expensive as DOT4
          fluid. It is also difficult to find, generally only
          available at selected auto parts stores." 


.  There is an excellent
> article by Ken Streeter at the VTR pages.

I'll say....

Has anyone on this list removed a master cylinder without spilling a 
little brake fluid on the paint underneath it? Even after draining 
it?

Anyway I can say I am VERY pleased with the DOT5 in my TR4A. Even 
though it still stings when you get it in your eyes. Ask me how I 
know....

"Still ride in triumph over all mischance..." - Shakespeare

Chris Lillja
TR4A
Norton Commando
Spit MKIV

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