Five years ago, I replaced my LMA fluid with silicone by pouring it into the
master and pumping until I saw the silicone come out at the slaves.
I have never had any problems with my system since. '77 MGB
Bill
----- Original Message -----
From: Florrie & Allen Bachelder <bachldrs@swva.net>
To: <mgs@autox.team.net>
Sent: Monday, November 29, 1999 9:43 PM
Subject: Re: Brake fluids and rubber parts
> Finally, after listening to the debate for years, ' thought I'd try DOT 5
> myself last summer. Despite THOROUGH flushing, in less than 400 miles my
> calipers were leaking. In 15 years and untold hundreds of thousands of
> miles, I have NEVER had an MGB caliper leak. You can bet I was back on
DOT
> 4 LMA (and new calipers!) in a matter of hours! I learned my lesson.
>
> Allen
>
> >From: Tab Julius <tab@penworks.com>
> >
> >Not to dig up an old thread :) but recalling the conversation on silicone
> >brake fluid and all that fun stuff, and came across this on the
> >mgcars.org.uk site....
> >
> >--------------------
> >A Tip for all MG's with Pressure Type Brake Light Switches
> >by Paul Kile, Fair Oaks, California
> >
> >For all of you with MGs that have pressure type brake light switches (
> >MGA's and MGBs/Midgets with single circuit brakes) - DO NOT use silicone
(
> >DOT 5 ) brake fluid in these systems, unless you want to replace your
brake
> >light switch every three months or so. Although none of the recent
debates
> >on silicone fluid seem to mention this, I have had three brake light
> >switches fail on two different cars, both using silicone fluid. Others on
> >the Internet have noticed this also. It appears that the silicone fluid
> >acts as an insulator and prevents the switches from making contact.
> >
> >The solution? Stick with DOT 4 fluid and change it yearly, or put in a
> >mechanical type switch on the brake pedal.
> >
> >--------------------
> >
> >'s true?
> >
> >- Tab
> >'78 B
> >
> >At 01:54 PM 8/30/99 -0700, Max Heim wrote:
> >>No, I think you are a little confused. *Silicone* brake fluid has never
> >>been accused of dissolving seals (or anything else). That is its chief
> >>benefit. DOT 3 or 4 brake fluid is notorious for dissolving paint
> >>everywhere it drips. It has also been known to dissolve the seals on
> >>LBCs, *except* for Castrol GT LMA brand fluid. Why is this? Who knows?
> >>DOT 3 and 4 are performance specs, not materials specs, so it is
possible
> >>that Castrol uses a different formulation than Pep Boys, Mechanics
Brand,
> >>etc. At any rate, there is plenty of evidence in on this subject, and
the
> >>recommendation is clear:
> >>
> >>Use exclusively Castrol GT LMA brand DOT 4 brake fluid, *or* completely
> >>flush your system and convert to silicone brake fluid (DOT 5, any
brand),
> >>since silicone fluid is incompatible with the other variety.
> >>
> >>Note that DOT 5 is not an "improved" spec compared to DOT 4, it is
merely
> >>a different chemistry with different benefits. DOT 4 = higher boiling
> >>point; DOT 5 = non-corrosive.
> >>
> >>Some people may not have had any trouble with "off-brand" DOT 4 fluid in
> >>their MGs -- if so, congratulations, but be aware that there are many
> >>different sources for brake system rubber components . The next time you
> >>rebuild, you might not be so lucky.
> >>
> >>'nuff said!
> >>
> >>
> >>James Nazarian Jr had this to say:
> >>
> >>>I have had dot 5 (silicone) in my brakes and clutch of my mg for about
5
> >>>years now and I haven't had a single problem. My understanding is that
> >>>the original and early replacement seals couldn't stand up to silicone,
> >>>but that the newer replacement seals (within the past 5 years or so)
are
> >>>designed with a slightly different compound will have no problems with
> >>>silicone. I don't know the difference in the two kinds of rubber or
> >>>fluids, but I would guess it is related to the same properties that
make
> >>>dot 3/4 take off paint and dot 5 prevent paint from bonding. So far I
> >>>haven't had any problems with the silicone, but I think there must be
some
> >>>truth to the rumor so I would make sure the seals in m/c and s/c are
> >>>fairly new.
> >>>
> >>>James Nazarian
> >>>'71 B roadster
> >>>'74 BGT bastardization with big aluminum heart :)
> >>>'63 Buick 215 cubic inch 'heart'
> >>>
> >>>On Sat, 28 Aug 1999, Larry Hoy wrote:
> >>>
> >>>> Ken Payne said (in part)
> >>>>
> >>>> > I used AP550 for a while ... and [it] seemed to be harder on some
seals.
> >>>>
> >>>> So can anyone tell me about rubber seals?
> >>>>
> >>>> What's the deal with certain brake fluids destroying certain fluids?
> >>>>
> >>>> Is this problem a thing of the past? Some how I gotta think that
today's
> >>>> brake rubber parts must be compatable with DOT 3, 4, and 5 brake
fluids?
> >>>> Can anyone enlighten me?
> >>>>
> >>>> Larry Hoy
> >>>>
> >>>>
> >>>
> >>>
> >>
> >>
> >>--
> >>
> >>Max Heim
> >>'66 MGB GHN3L76149
> >>If you're near Mountain View, CA,
> >>it's the red one with the silver bootlid.
> >>
> >>
> >>
> >
>
> mg-mg-mg-mg-mg-mg-mg-m-gmg-mg-mg
>
> Allen Bachelder
> '73 B - "done"
> '76 B - daily driver
> '73 GT - awaiting front wings
> '65 B shell - awaiting paint
> '67 GT - awaiting everthing
> '57 ZB - parts car or resto-candidate? - awaiting decision
> '49 YT - in "progress"
>
> mg-mg-mg-mg-mg-mg-mg-mg-mg-mg-mg
>
>
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