Hey today I'm going to talk about Brake Fluids and you know what I've really
been looking forward to this yarn, this is a really interesting topic because
for me brake fluid is one of the most underestimated, underrated fluids in your
cars, that has such a profound impact on your braking you might not think so but
that is absolutely the case. Now you know we're in a race environment here and
absolutely it has evolved over many years and racing has been right at the
forefront of that evolution because of the heat generated in the brakes so
let's understand them. From a specification point of view you kind of
start down at this end with what's called DOT 3 then there's DOT 4, DOT
5 and so on that pretty well covers it doesn't go far beyond that. Now when
we look at our brake fluids let's understand the difference between the
different grades and what's applicable, there's two fundamental differences as
we go up the ladder, One is its boiling point, just like boiling water, At what
point does pure brake fluid actually boil? Now a racing brake fluid obviously
boils at a much higher temperature than your road car brake fluid, now we'll get
to that. The other really critical thing which is expensive to develop, is a brake
fluids propensity to absorb moisture, now all brake systems through seals and
other mechanisms will absorb moisture into them, moisture is a bad thing in a
brake system, because it does two things. One it's going to lower, right
your boiling temperature of the pure fluid right, that's going to come down
it's got water in it now quite obviously as a result of that boiling vaporisation
means your pedal is going to go soft and that's a really bad thing, so when we
talk about fluid specifically at the lower end DOT 3, now that's got to be
perfectly fine in the vast majority of road cars for which it's used, most
manufacturers just specify that at a service schedule, but if you want to go
up a step you can go up to DOT 4 you can see there the number 4, now that's different
in that the boiling temperature is up a little bit and the propensity to absorb
moisture is also less which is a good thing, now that'd also be good for
example if you've got a the modern specifications call for it,
that you might have a heavier brake application or if you've got a load, a
truck whatever or if you're towing a big old Caravan and you're going down the
hill and riding your foot on the brakes can't think of a better way to get your
brakes speaking hot and boil your fluid so that might be perfect if you're
in a towing environment. Then we go to the next level of fluid which is kind of
in the modern era this is called brake fluid right, DOT 4, same as this but ESP
that stands for Electronic Stability Program, so many modern vehicles we
know now have avoidance programs, anti-lock brake systems, if you've ever
put your foot on the brake and felt that in operation you'll feel the frequency
at which it applies the brake per times per second to maintain the grip of the
tyre, a slipping tyre, remember a locked tyre doesn't provide grip so what that does
that has a variety of treatments in it and viscosity applicable to the really
really fast reaction required from the brake system in a modern braking system
so that's good for a modern car, and then we go up to racing brake fluid now I can
tell you Davey Reynolds who won Bathurst 2017 for 161 laps at the end of
Conrad straight at nearly 300k's an hour they generate just under a thousand
degrees centigrade brake temperature on the discs there, use that every single lap
to stop him so that's how good that stuff is.
Do you need any road car? No, of course you don't because you're just not going
to generate that sort of heat if you want to put it in there by all means do
it it's not cheap as some of these ones but it is very very good I'm not
recommending you need it for your road car though,
and then over here sitting out all on its own
Silicon Brake Fluid, now don't confuse that with synthetic brake fluid,
most modern brake fluids are synthetic this is silicon brake fluid so, it's
actually a heavier brake fluid it doesn't absorb any water at all but it
kind of has different properties so that's best used where the manufacturer
calls for its use in its particular application, but it is a good one, now
there's plenty more information on all of these because I could be here for an
hour talking about it, jump on Penrite Oil's website and knock your socks off.
you