Bob Danielson wrote:
> With my new brake MC due to arrive Friday or Saturday,
>
> The more I google "DOT5 Brake Fluid", I don't get a warm fuzzy feeling about
> it but I know a lot of you folks are using it in your cars with much
> success.
>
> What's your experience been?
>
> Bob Danielson
>
The short response since the long one did not make it:
Unless you are absolutely sure you have no natural rubber seals in your
system, the only Dot 3 or 4 you can use is fluid that specifically
states it is safe for natural rubber. This is why you do not flush your
system with mineral oil - mineral oil attacks natural rubber. Ever see
that little curl of black pop back up in your reservoir? That is the
fluid attacking a natural rubber seal and if you see it, it is already
too late.
The problem is that there are so many New Old Stock Girling / Lockheed
seal part kits floating around for calipers, slave and master cylinders
that were made of natural rubber or natural rubber blends, you do not
know what you are getting for seals. There are at least 10 rubber seals
in your brake system.
I only know of two fluids that are specified to be compatible with
natural rubber seals, and that is Castrol Crimson (or maybe Stirling?)
Brake Fluid, and Silicon DOT 5 with no Ethyl or Ester glycols.
North American formulations of DOT 3 and DOT 4 will cause natural rubber
seals to soften, swell and leak in a very short period of time. If just
one of those seals contains natural rubber and you use a NA formulation
of DOT 3 or Dot 4, it will leak.
My use is almost 5 years in a Stag, no problems or evidence of dirt in
either brake system or clutch system.
--
Glenn A. Merrell
Chairman, Triumph Stag Club USA (2007-2009)
The best trophies are miles on the odometer, stone chips in the paint, dead
bugs on the windshield!
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