I'm running silicone fluid in my '72 Midget, going on 5 years with no
problems. I'm going to go back to Castrol Girling fluid, for the '73
that I'm working on, now, and flush/renew the fluid in the system every
two years, like the shop manual recommends, just to see what sort of
service life I can get.
One warning, about silicone brake fluid, however: It is not a good idea
to use in a vehicle with vacuum servo assisted brakes. The reason, as
detailed in an article I read in Vintage Truck Magazine (published by a
Porsche 356 guy, and has some EXCELLENT technical articles......and I
like old trucks), is that in the event of a fluid leak, into the servo,
and with a servo leak too, brake fluid is drawn into the combustion
chambers. Conventional brake fluid just burns off, with no residual
effect (other than the eventual loss of brakes), while silicone fluid
"cokes", leaving a silica sand residue...... Who'd a thunk it?
Oh, BTW, the VT article said that, as long as the seals didn't react
(swelling) to the silicone, you needn't flush the system (to remove the
DOT 3 or 4 fluid), and change the seals when converting to silicone.
The silicone and DOT 3 or 4 fluids will NOT mix/combine to form
something else. So, no worries, mate.
Bud Osbourne (tickled to be back from a computer "issue")
-----Original Message-----
From: owner-spridgets@autox.team.net
[mailto:owner-spridgets@autox.team.net] On Behalf Of Frank Clarici
Sent: Monday, March 27, 2006 5:43 PM
To: SDOliner@aol.com
Cc: spridgets@autox.team.net
Subject: Re: Brake fluid question
Ok, I know Allen hates sillycone brake fluid, he always did ;)
But I have had it in the A40 since 1997 and other than the NOS clutch
master giving up it's seal, no other componants have failed.
I wish I can say the same about PIECES which is still running DOT 4.
10 or 11 years old now and on it's 3rd brake master, and at least it's
second clutch hydraulics set.
I know a guy with silicone in his big Healey, 12 + years and no
hydraulic troubles.
My Bugeye is now on silicone, no problems in the past 3 years.
The rally car is on silicone too but it's too soon to tell on that car.
It seems to me the seals fail after 4 or 5 years with DOT 4 even if the
cylinders are new.
Yes you have to start fresh with all new cyls or seals before using
silicone.
Silicone is PURPLE for that very reason. Do distinguish it from the
others.
If you shop silicone fluids, you will find it from $7 a QUART to $20 a
PINT. Kar Parts has the $7 a qt stuff. Pep boys has it for $19.95 a PT
so do shop it. And yes I know qts is twice as much as pts.
--
Frank Clarici
Toms River, NJ
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