How to bleed Hydraulic Clutch
How To Bleed A Hydraulic Clutch - Wrenchin' Up
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we're at the test labs that perfection
collection Charleston South Carolina
because you know sometimes when you're
doing a hydraulic clutch job on the
vehicles like Oh a Ford Ranger or a
Honda Civic it can be very difficult to
get the air out of the line sometimes so
we're going to take a look at how that
air gets into the hydraulic lines and
the best way to get it out let's get
started and of course we can't really
see the air bubble in the line so here's
a great little display that will help us
understand that so Gary I guess here's
the air bubble what else is going on
here
Jim basic Ford Ranger system master
cylinder paddle assembly line slave
cylinder and a clutch right now we don't
have the air bubble in this system so
when I push on the clutch pedal the
pressure plate is going to allow the
disc to spin down freely shifts normally
the way it should bring the pedal up the
clutch engages now let's add the air
bubble so when I open this valve we're
going to add this air bubble to the
system it'll compress first Wow the
fluid is compressing the air bubble that
gives us fine GL we lose pedal travel we
lose plate lift on the clutch and we
don't get a clean clutch release we're
talking about gear clash grind inability
to select reverse and first from a
standing start so we got to get that air
bubble out and not to mention the wear
on this collection disc itself so all
right this air bubble we can see here in
the line but on the vehicle where does
it come from Jim we find it's almost
always a trapped air bubble in the
master cylinder the bubble sits up here
and you can see in this demonstration
with this water bottle as long as that
bubble is up there it's not going to go
out down through the line so we teach a
technique where you tip the master
cylinder so the bubble can actually go
back out the top this is done off the
vehicle on the bench no special tools
required and you can feel the change in
your own hands when it's ready to
reinstall well that makes a lot of sense
so let's go back to the vehicle here and
check it out there well Gary this f150
has a similar problem to the Ranger that
we were talking about yes the clutch has
been installed but it has a soft pedal
so what's different though is the clutch
master cylinder is horizontal not tip
does that make a difference a little bit
they have the same internal design the
Ford Ranger it's tipped pretty
dramatically the air bubble is really
trapped up here this one looks like it
shouldn't be a problem
but even horizontal the air bubble is
still trapped in the top half of the
pressure chamber of the master cylinder
bore so to get it out we have to take it
off the chassis tip it will exercise the
push rod back here and the valve will
open close and the bubbles will come out
the top of the reservoir if the
instructions were followed that we offer
we wouldn't have this problem and we
would get it bled out on the bench
before we install it and then finish for
the gravity bleed it's not such a
problem after all right well show us how
it's done
okay tell us what has to be removed for
a procedure like this this vehicle we
had to remove the master cylinder
reservoir the master cylinder and the
pressure line this allows us to take it
to some object a ladder a stand like
this
we stretch it out reservoir at the top
master cylinder very important that it's
angled this way connection up push rod
down and the connections at the bottom
if there's an air bubble in the system
we can actually push it out the top very
simply and none of the procedures that
are commonly used vacuum bleeding
reverse fluid injection will do this
in the truck they just aren't effective
putting it like this the bubble is going
to go up which it wants to do anyway Jim
if you'd remove the cap and the little
seal underneath there over that on your
brake fluid yep okay now if you want to
step up on the ladder you'll be able to
see the bubbles as they come out the top
okay careful sir all I'm going to do is
exercise the push rod a little bit and
that valve triggers the bubbles to come
out the top coming out already so the
further the push rod pushes that's more
air when it tightens up and gets to
about 1/8 of an inch that's when we get
to reinstall it and finish it with a
gravity bleeding well Jim after we got
all the air bubbles out of the master in
the line we had it stretched out now
we're going to put it back in the truck
make the connection of the pressure
connection to the slave cylinder and the
gravity bleeding process all we have to
do is open the bleed screw and the
system will flush itself the fluid comes
in to the bottom of the slave zone or
pushes the
bubbles out the top typically we wrecked
we recommend flushing about one and a
half two reservoirs worth of fluid
through the system close the bleed screw
and this clutch is bled and ready to go
when you open up a box of a perfection
clutch project this is the first thing
you're going to see and it has a 800
number for technical support and a
website where all the details
instructions are on the back is a great
quick start procedure to get you going
but if you follow these procedures and
the technical instructions on the
website they'll never be in a position
where you have to remove this product
and rebleed the system again
you
