Rev up your engines,
today I'm going to be talking about the best brake fluid for your car and why it's so,
now brake fluid makes your brakes stop so, here's a little history lesson to show you
what you should use by learning from history, now in 1924,
hydraulic brakes were first used on mass produced cars,
and yes that was before my time, they were alcohol or caster oil based,
and they worked ok for those old cars, but there boiling point was too low for any
modern cars, in modern cars, rarely do your braking system,
the rotors and stuff, get above 400 degrees fahrenheit,
but the boiling point of this old stuff was 374 degrees fahrenheit, so it could make it
boil, and guess what, you don't want your brake
fluid boiling, is worse for your brake fluid to be boiling
than even your engine water, because if they boil, the brakes will stop
working, they will just fade away, the early system were called DOT 2,
you can't really buy that stuff anymore, now even when I was a young mechanic in the
60's, almost all the systems used the more modern
stuff that's called DOT 3, it means department of transportation, it's
a rating system, but back then we just called it brake fluid,
no one was even thinking about that stuff, we just poured it in and used it and didn't
think about what types you need, the DOT 3 is a glycol ethers based brake fluid,
and it's boiling point is 401 degrees fahrenheit, and since the rotors rarely get above 400
degrees fahrenheit, that's good but still 400 or 401 degrees,
if you drive really hard, you might think about something else,
like DOT 4 which is a glycol borate mix, and it can go to 446 degrees fahrenheit,
so your never really going to have to worry about boiling the stuff out,
now many modern cars now come with DOT 4 brake fluid,
it's really top of the line for mass produced cars,
now there is DOT 5 fluid, which is a silicone based fluid,
but you can't use that in most modern cars with ABS because it messes with the ABS system,
the DOT 5 main use is in military vehicles here in the United States,
because it's not based like the other ones are,
it's a silicone based thing, so it does not absorb water moisture,
so you never have to worry about water moisture contaminating your system,
so the military loves it because if they're in really cold places,
they don't have to worry about water getting in the system and it freezing and then not
working when it's really cold, but you really can't use the DOT 5 in many
car, the silicone ones don't mix with the other
type ones that are based on different chemistry, and like I said it can destroy the ABS system,
somehow it foams up or something and it just won't work right,
so you can't use DOT 5 on any car your driving on the street,
of course the military loves DOT 5 because since it doesn't absorb water, they never
need to change the stuff, they can leave it in there pretty much an
infinite amount of time and they're not going to have any problems from the system's fluid
going bad, but scientists being what they are,
they've invented now DOT 5.1, it has the same boiling temperature as the
silicone based 5, which is 500 degrees fahrenheit, but being a glycol borate mixture, it can
be used with any of the other systems, you can put DOT 5.1 in DOT 4 or DOT 3,
you don't have to flush anything out, it can work perfectly fine with any of them,
where the DOT 5 you can't mix with anything except DOT 5,
so the DOT 5.1 is really the best brake fluid you can buy for cars you drive on the street,
you might not necessarily need that much if your not braking like a maniac, the DOT 4
will work perfectly fine for most people, so really for conventional driving,
the DOT 4 fluids are perfectly fine to use, but if you want the absolute best with the
highest boiling point, you get DOT 5.1 and if your thinking about switching your
system over to 5.1, the great thing is, say you want to flush
it out and put the new stuff in, you don't have to get every little drop of
the old stuff out, because they mix perfectly fine,
if you had a tiny bit left, maybe instead of having a boiling point of 500 degree fahrenheit,
maybe it would be like 460 or 470 but still that's way higher than what you need,
and this being mechanic monday, I'm giving away a bottle of the DOT 5.1, even
though it's super expensive, and remember to get a chance to win, just post a clean
non offensive comment on the YouTube comments below,
and a winner will be randomly chosen by a computer to get a bottle of this stuff,
so if you never want to miss another one of my new car repair videos, remember to ring
that bell!
