[alfa] RE: Time for Brake MC

[Joe Elliott <jee@xxxxxxxxxxxxxx>]

I think I know a thing or two about rust from empirical experience 
(those of you who have seen my car know what I'm talking about). 
There's no reason why a DOT 3/4 brake fluid would promote caliper 
piston corrosion unless the caliper is leaking, and even then I find 
it unlikely since they're not painted, and are obviously made of a 
metal that can stand up to brake fluid.  DOT 5 on the other hand will 
leave you with a pocket of pure water right behind your caliper 
pistons, as Jeff eluded to, that will rust the pistons from the 
inside out, not to mention boil almost immediately should you give 
your brakes the slightest workout, and leave you with 
practically-useless brakes.  If you're happy with it, fine, but don't 
delude yourself as to the potential benefits.  I'll also say that if 
I were a tech inspector I'd be reluctant to let you on a race track. 
I know I'd rather change brake fluid every 2 years rather than take 
the risks associated with silicone fluid.  And for what it's worth, 
my car sat outdoors in the rust belt for 3 years before I bought it, 
with DOT 3 fluid in it, and to this day (4 years and over 30,000 
miles later) the front calipers are doing just fine.  (I run ATE 
Super DOT 4 fluid.)

Joe Elliott
'82 GTV-6

At 3:40 AM +0000 10/23/03, alfa-digest wrote:

> Date: Wed, 22 Oct 2003 22:26:08 -0400
> From: "Jeff Greenfield" <alfaguy@domain.elided>
> Subject: RE: [alfa] RE:  Time for Brake MC
>
> I hate to open the silicone vs conventional brake fluid thread again, but
> ...
>
> I've seen more than a few cars in the North East that are stored during the
> winter that when filled with silicone fluid the calipers rusted as badly (if
> not worse) than cars filled with conventional fluid.
>
> Problem is that the silicone fluid does not mix with the moisture that is
> absorbed into the system. This means that the moisture settles out and tends
> to accumulate in the lowest part of the system which is usually the brake
> caliper(s).
>
> Conventional (DOT 4) fluid will absorb the moisture and as long as the fluid
> is changed every 1 to 2 years you will seldom have a problem with corrosion
> in the system due to moisture.
>
> BTW, in case anyone is wondering ... the LMA in Castrol DOT 4 brake fluid
> stands for 'Low Moisture Affinity' :-)
>
> Now, I'm sure some of you may have other opinions pro and con, this is just
> mine and you are more than entitled to yours. I really don't want to see 100
> or more messages in the next few days regarding the pros and cons of
> silicone brake fluid. I'm gonna stay out of it from here on in ...
>
> I now return you to your regularly scheduled discussions of free Berlinas,
> 164 fault codes and stepper motors, spica vs weber debates, and the proper
> methods of engine break in procedures :-)
>
> Jeff
>
> - -----Original Message-----
> From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided] On Behalf Of Gil
> Gagne
> Sent: Wednesday, October 22, 2003 8:50 PM
> To: alfa-digest@domain.elided; jee@domain.elided
> Subject: [alfa] RE: Time for Brake MC
>
> Joe,
> Alfa owners in the rust belt states certainly have a different opinion
> of DOT 5 brake fluid than you do. Some of us have been using it for
> years and years without the problems casually attributed to it such as
> soft pedal. Once properly installed, you can forget about caliper piston
> rust, a distinct advantage for vehicles stored six months of the year.
> Gil
> Port Orange, FL
> 1985 Spider
>
> > Simply put, don't use DOT 5 fluid in any vehicle that's
> > driven seriously.  That stuff's for military trucks, Harleys, and
> > museum piece vehicles.  And I think some fools use it in go-kart
>  >racing, although I can't imagine why.
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