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!
