rev up your engines, today I'm gonna show you how to fix a very common problem
that occurs in cars and that's a mushy brake pedal, now the owner of this Toyota
is complaining that they bought it brand new and over the years the pedal starts
getting moisture and going low to the ground, they've had people look at it but
nobody's fixed it, now years ago I used to be pretty simple if your brake pedal
was getting mushy you either had a leak in somewhere in a system that sucked air
in, and when you press down the air compresses a lot more than brake fluid
or you had a bad master so that when you pushed on it, it didn't send the fluid
out right and it got mushy, but of course modern cars are got more
complex, now they have ABS systems and if those modulators go bad they can open
and close at the wrong time and give you spongy brake pad, so your gonna
need a mechanic like me to check that fancy stuff out with a fancy scan tool
now if your ABS lights on that's gonna give you a code that shows you the problem is
but a lot of times they don't trip codes and you're gonna need a machine like
this in order to go through the whole stinking ABS system to activate stuff
now to activate them see what kind of data is coming out can get pretty
complicated, now since I have one of these machines that's the first thing I
did, I went through the system and there was no ABS problems everything was
working ok, so I know it's not the ABS system, guys you can't do it yourself but
at least I got rid of the thing that's going to be super expensive first, now I
always like to get the complex possibilities out of the way first but
you're not gonna be able to do that so what you do is get a nice flashlight
check all the wheels to see if there's any leaks, if there were leaks there would be
brake fluid leaking and you'd see it then, in this case I looked all around
the front calipers were dry, the rear calipers are dry there's no sign of
leaking brake anywhere under the vehicle, and any way that's the customers, the
original owner and the brake fluid is still full I asked him if they've been
adding brake fluid and he said no they haven't had to add any brake fluid to it at all
then I know there's no physical leaks, they had some other mechanics over the
course of years bleed air out of the system but that was really a mistake on
those mechanics behalf, if you have air inside your system it's gotta come from
somewhere, so if you just bleed the breaks that isn't gonna fix anything
because it's gotten there somehow and if something's leaking and then when you
take your foot off the brake it sucks air through that leak that
won't fix anything, so bleeding brakes is not a way of fixing anything in a modern
car, you have to find the problem then fix the problem then if you had to open
the system out then you have to bleed the air out of the system, you can't just
say oh I'll bleed air out of the system if error is in there it's enough of a
reason, and you got to find the reason that air is in there so knowing these
Toyota's after working on it for decades I'm gonna change the brake master
cylinder cuz it's just not building the pressure up right it's not
losing fluid, there's no leaks anywhere, and the ABS system doesn't have any
weird codes, and when I tested it with my fancy computer all the systems seemed to
be working perfectly fine, odds are the master cylinder it's just worn from
aging that's very typical with Toyota vehicles as they age a lot of them get a
sinking brake pedal that's really nothing to worry about cuz normally just
sinks so far and stays there but the customer doesn't like it so I'm gonna
put this in see what happens, now again so we just moved the airbox
out of the way with the air filter because the master cylinder is here and we
need to get to the bolts, now as the brake lines that come off
the master cylinder are sometimes hard to get off, so I use these little crow
foot wrenches, this is ten millimeter it fits right over the line and get some
loose without stripping them, as you can see right here it fits over and then
when you pull on it hmm, you get them loose and once it's loose you can use a
regular wrench just down screw it and then use your finger to get the line out
of the way they're pretty long but eventually get to them to come off
and you do the back one the same way, huh loosen that then you get a 12 millimeter
socket and remove the two bolts that hold it in place, sometimes you got tug
a little bit then it comes out, here we go we know it's bad cuz fluid is leaking out
of the inside, this should not leak this should be perfectly dry inside it's not
so we know this is bad we're gonna replace it, now we want to hope for
doesn't leak so get my pump I'm sticking the inside
I'm gonna see if any brake food is inside there and luckily my pump isn't
pumping any brake fluid out of the brake booster so it should be okay and not
damaged from fluid filling it up, so now we get the new cylinder and it just goes
right in you line it up with the two bolt holes a little wiggling here, then
we put the two bolts on they get the nuts on nice and tight you want them
snug, now to bleed the air out it's easier with two people first you have
someone inside you tell them to step down on the brake you keep your fingers
over the two openings and then you do that two or three times where they step
on the brake you let the air out put your fingers back on they pick it up and
then you say push it down again you pick your fingers up in the air gets out then
you put the lines on, okay push it down pick it up push it down okay then you
get them nice and tight while their foot is still on the ground and then you tell
them to pick it up, pick up, the brake pedal that sucks the air out now I'm
gonna crack both lines and then they have to step down that pushes air
through then you tighten the lines and they pick it up and you do that four or
five times okay push it down and guess what now it's got a nice firm pedal that
doesn't think now as you can see a new master cylinder fix the problem but
really there was no way you knowing this thing was leaking on the inside because
you couldn't see it without taking it apart you have to do all the logical
diagnosis first, and then when you can't find anything else wrong you guess that this
is bad, now when you took it apart and follow the fluid coming out you know
it's bad, so the next time your brakes start to get mushy now you know how to
fix them yourself, so if you never want to miss another one
of my new car repair videos, remember to ring that Bell!