[Healeys] silicone brake fluid

Sun Jun 16 10:50:11 MDT 2019

Entirely correct.

DOT4 will be perfect for most users. DOT5 for the silicone boys. DOT5.1 
is similar to DOT4 but is upgraded to more or less the same properties 
(e.g. boiling point) as DOT5 but absorbs water and is compatible in 
practically all classic car braking components. It is better suited to 
extreme driving compared to DOT4. It may also have a harder pedal as it 
is non-compressable. DOT5 is slightly compressible and can feel a bit 
spongy when you are not used to it. Most won´t notice anything.

ALL brake fluids should be replaced on a regular bases, usually every 2 
years, in very damp environments more often.

Kees Oudesluijs

Op 16-6-2019 om 18:15 schreef simon.lachlan at alexarevel.plus.com:
>
> When this came round last time, I did a little digging and came up 
> with this, which I believe I may have inflicted on you before. It was 
> written for our local (UK) club magazine but I’m sure that most of it, 
> if not all, is universal. It’s more about what mixes with which rather 
> than which rots what. If you get my meaning….
>
>  1. All brake fluid is “synthetic”…it’s not a “natural” product.
>  2. Most synthetic fluids are NOT silicone. They are polyethylene
>     _glycol_ ether based.
>  3. DOT 3 & 4, which can be mixed, are not silicone. They are glycol.
>  4. DOT 5, which cannot be mixed with 3 or 4, is silicone. Can’t be
>     mixed with anything!
>  5. DOT 5.1 is glycol based and cannot be mixed with DOT 5.
>  6. DOT 5.1 can be mixed with DOT 3 or 4, as both are glycol based.
>
> Simon
>
> *From:*Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Bob Spidell
> *Sent:* 16 June 2019 16:34
> *To:* healeys at autox.team.net
> *Subject:* Re: [Healeys] silicone brake fluid
>
> I've used silicone BF in my BJ8 for close to 30 years (and when I 
> replaced the brake MC, 15-20 years and 80-100K miles ago, I 
> disregarded the same warning).  As somebody mentioned, your problem is 
> symptomatic of the 'check valve'--aka 'foot valve--malfunctioning or 
> damaged.  I had similar problem with my brakes on a long road trip; 
> had to pump the pedal a couple times on every application (for a 
> couple thousand miles).
>
> We put the highly-touted Castrol BF in our 100M after a thorough 
> restoration--with all-new brake system--and the fluid jelled when that 
> car sat for a couple years.
>
> Side note: Most BFs are calling themselves 'synthetic' these days.  
> Are they a new formulation, or just jumping on the bandwagon as, 
> AFAIK, BF has always been synthetic (the glycols used don't occur in 
> nature)?
>
> Bob
>
> On 6/16/2019 7:44 AM, Team.net wrote:
>
>     I have used silicone in all my british cars for 25 years with no
>     problems
>
>
>     On Jun 16, 2019, at 09:31, HealeyRick <healeyrik at gmail.com
>     <mailto:healeyrik at gmail.com>> wrote:
>
>         Apparently, silicone can cause swelling of the seals in
>         Girling and Lockheed systems: http://www.gomog.com/brakes.html
>         I have a Howe hydraulic clutch in my Nasty Boy, and that also
>         came with the advisory not to use silicone fluid.
>
>         Rick Neville
>
>         On Sun, Jun 16, 2019 at 8:24 AM Brian Drab <bgdrab at redzone.ca
>         <mailto:bgdrab at redzone.ca>> wrote:
>
>             Last week I completed a driving tour in our BJ8. It was a
>             great tour and everything ran well except for one thing.
>              4 or 5 times, when I used the clutch, the clutch master
>             cylinder bypassed. The rest of the time it worked well. As
>             I don’t want to be caught without a clutch at a later date
>             I am changing the clutch master cylinder. I have received
>             a replacement and am preparing to install it.
>
>             On the box is a quick summary of the bleeding procedure
>             under a warning – “Using Silicon Brake fluid will void
>             warranty”. I have used silicon fluid for well over 10
>             tears and never experienced any problems with it and have
>             never seen or heard of this type of warning before. I have
>             never heard of any destructive qualities of Silicon fluid.
>
>             My question is – does anyone have any idea what it is about.
>
>             For me to change to Dot4 fluid is quite a big deal as I
>             would be changing out the clutch as well as the brake
>             system seeing as they share a common reservoir.
>
>             I’d appreciate any comments on the warning.
>
>             Brian Drab
>
>             BJ8
>
>
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