Quick Summary: (This is a "list consensus", so individuals may disagree.
I hope this formats OK)
PRO: CON:
DOT 3 Cheap Eats natural rubber seals
Easily available Eats paint
Lower boiling point
Actually draws water from air
DOT 4 Cheap Eats paint
Doesn't eat natural rubber Still draws water, but not as
much
Higher boiling point
DOT 4+ Draws almost no water Eats paint
Very high boiling point More expensive than DOT 4
Doesn't eat seals Harder to find
DOT 5 / Doesn't eat paint Expensive
Silicone Doesn't eat rubber Difficult to bleed all
the air out
Very high boiling point You should only change over when
Doesn't draw water at all replacing all the
rubber in the system.
Relatively easy to find.
Consensus:
DOT 3 DO NOT USE!
DOT 4 OK
DOT 4+ OK
DOT 5 Depends on who you ask.
PERSONAL OPINION:
Some people complain that DOT 5 / Silicone (a) gives a softer pedal, (b)
causes systems to leak, and (c) allows water to pool in the hydraulics
(because it won't absorb it). I have been running silicone for 3 years now
without a problem. I figure that (a) anything will give a soft pedal if
you don't get all the air out, which is more difficult with silicone, (b)
Since silicone causes rubber to swell less DOT 4, a system changed over
without replacing all the rubber in the system will leak, and (c) I can't
figure how the water that would hypothetically pool would get in there in
the first place.
Anyway, as far as I know everyone agrees that you won't go wrong with DOT 4
or 4+. People who are really worried about screwing up their brand new
paint tend to go for DOT 5.
Chris Kotting
ckotting@iwaynet.net
P.S. "Silicon" is a mineral used in making glass and semiconductors.
"Silicone" (note the "e" at the end) is a synthetic liquid used in
lubricants, breast implants, and some brake fluid.
On Friday, August 14, 1998 9:55 PM, Michael O'Higgins
[SMTP:roterhed@email.msn.com] wrote:
> Let's talk about brake fluids. I would like information about the merits
and
> contraindications of DOT3, DOT4, and silicon brake fluids. What are your
> opinions as to the appropriate fluid for my newly refurbished Bugeye and
on
> what information do you base them. Looking forward to hearing from you.
> Cheers...
> Michael O'Higgins '60 AN5L40325 "Raj"
> Roterhed@msn.com
> "Good judgement is the product of experience."
> "Experience is the product of bad judgement."
>
>
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