in today's video we are going to
troubleshoot a vehicle that is losing
brake fluid and we're going to go over
this a little bit more detail as we look
at the vehicle but what basically what
is happening here's the master cylinder
of a vehicle this is the reservoir here
for the brake fluid and what has
happened in this particular vehicle is
the brakes had become really soft the
brake pedal was really soft almost to
the floor so when I checked it out the
brake fluid level had gone from a
maximum up here down way down to the
minimum so obviously the first thing I
wanted to do then was I topped it up
full of brake fluid pumped the brakes a
bunch of time to times to regain the
brake uh pressure in the pedal and then
I used it now when I say use it be very
careful with that term I would not take
a vehicle with questionable brakes out
onto the h highway I took it around a
remote Country Road pumped the brakes a
bunch of times used it a bit and the
fluid has gone down a little I was
hoping it was actually going to go down
a lot because obviously this brake
system is losing fluid somewhere there
should not be any leaks in a brake
system so um when I when I as I say when
I filled up the fluid level in the
reservoir for the master cylinder it
went down a bit but basically now we're
going to take it to the next step and
troubleshoot this and see where the
why we are losing brake FL so here I'm
going to demonstrate what I was talking
about as far as a lack of pressure in
the brake system itself when I push the
brake
pedal you can see how
easily that is going
down now I have the vehicle running so
this should regain pressure faster with
the uh motor running adding power to the
uh power brake system but uh I'm not
going to I don't want to drive this
pedal down too far because it's going to
Overdrive the plunger in the master
cylinder probably won't do any damage
but I don't like to to over stress the
system but here you'll
see that basically goes right to the
floor and I pumped the bun the uh brake
pedal a bunch of times that should have
regained some pressure by
now okay so what I'm going to do now
because of the fact that this vehicle
has lost so much brake fluid I'm
assuming that we probably have a fairly
obvious leak
here so what I've done is we've driven
the vehicle onto a
tarp so I'll have a surface uh that I'll
be able to see the brake fluid if it
comes out now if I can narrow this down
to a leak in one particular wheel then
obviously I've cut 3/4 of my
troubleshooting
down so what I'm going to do now is I
have a person in the car we're going to
get him to pump the brake bres and then
I'm going to look in the tarp and see if
I can see brake FL so if you want to
start pumping the
[Music]
brakes
okay I'm just going to have a little
look here so
my the person in the vehicle is pumping
the BR start the vehicle because when he
starts it that's going to put way more
pressure on the brake system when he
hits that brake paddle because the power
brake system is going to kick in which
is going to amplify the pressure that
he's putting on the brake pedal so if
you want to start the car we'll get you
to be very careful doing this too by the
way you want to stay clear the any
moving components around the engine or
anything like
that okay so we had a major technical
difficulty we didn't have the car keys
so now we do so I'll get my driver to
start the
[Music]
vehicle okay so now with all that
additional force that he's going to be
able to apply when he hits the brake p
I'm just going to get them to don't
floor the brakes cuz we don't want to
overdrive that piston in the master
cylinder we if we can avoid it I just
pump it up and down a couple times keep
going like that you keep pumping them
while he does that he's got the
emergency brake on too by the way and I
have a block over on that other wheel
over there be very careful doing
this so just keep pumping
them I'm going to see if I can see that
leak okay so we're going to get our
driver to keep pumping our wheel and I'm
also going to have a look at the master
cylinder
[Applause]
level okay there's no use in keeping you
waiting while we're doing this we're
going to keep putting some pressure on
the system and see if uh we can narrow
down where our leak is
okay so I looked at our tarp which I
made sure was totally dry before we
started this process and here's what
we're looking for over here this was the
position of the rear wheel on the
driver's
side and there's not a lot but there's
some fluid there so that narrows our
problem down to the uh wheel that has
the issue our leak test with the tarp
did not leak lead us astray we saw some
brake fluid on the
tarp um on the uh driver's side of the
vehicle rear wheel there wasn't as much
fluid as I expected but we were just
pumping it as the vehicle was sitting
idle it wouldn't have lost the same
amount of uh brake fluid as it would
under real world conditions when a
driver be up in the road and hitting the
brakes and we see the leak here the we
can see why it was just a little bit of
fluid on the tarp
because what we got is the fluid is
leaking
down over this piece of metal here I'm
just going to compare it on the other
side hopefully you'll see there the uh
exact same piece of the frame there is
nice and dry see if I can point my
finger over there little tight Quarters
here that's good and dry but if we go
over to this
side we can
see that it is wet where the brake fluid
has leaked down now hopefully see if I
get my camera over there and you can see
what we're dealing with here up
above right there I'm hoping this will
come out is our brake line we can see
that the brake line is all
corroded so we're going to have to
replace that brake
line okay I'm just doing this again I
crawled into a better position I think
the light will show this better there's
our corroded brake line here there's the
fitting and if we follow that brake line
here we'll see it goes up
into the back of the drum up there so
there's our offender our offending brake
line okay so that's the end of that
video we uh had a leak in our master
cylinder just to summarize uh it went
down extremely low we topped up the
fluid um it didn't go down nearly as
much as it had originally but all that
fluid had lost in the first place was
over a period of time now what I'm going
to do here is a a little something
different I'm going to this will be the
end of this video troubleshooting the
master cylinder brake fluid leak
changing the brake line is going to be
the next video