Corolla 2001 brakes bleeding

I have "managed" to empty one chamber of master cylinder brake fluid
container
during brake job on the front passenger side. So, now I need to bleed the
system.

1. Since only one chamber of reservoir was emptied will it be OK if I bleed
only part of the system which was emptied in this case the driver back and
next passenger front (in that order - I understand Corolla has a diagonal
brake system) ?

2. Should I bleed emptied part of master cylinder by loosing the line at the
mc or any air will be pushed out when brakes are bled, and what about
front/rear distribution block?

3. Instead of using helper/pedal method can I use gravity method by opening
the bleeding nipple with hose on the end submerged in bottle with fluid (it
will take longer but not require helper)?

gravity bleeding will work fine and it's best to bleed the whole system at
the wheels. you shouldn't have to crack the lines connected to the brake
master. I've done it many times with all the brake jobs done in the past.
just remember to keep checking the master cylinder reservoir to make sure is
isn't going dry again or you're doing double work. work 1 wheel at a time,
cracking the bleeder screw and let the fluid drip. let it drip until clean
fluid emerges. also, keep the cap on the master loose or off so a vacuum
isn't created as the fluid is drained. note: since one chamber of the
master went dry, as the fluid is dripping from the first bleeder screw
you've opened. tap the end of the master cylinder with a hammer to help
dislodge any air bubbles trapped inside the master. just don't pound on it
since it is a cast aluminum body. once you've bled all 4 wheels, pump the
brake pedal a few times, making sure not to bottom out the pedal (or you
risk killing the master cylinder). this will cause the caliper pistons
caliper pistons to move back into their proper position if they were
compressed while changing pads. it will also help to work loose any air
bubbles that may have remained trapped in the brake system. now, just bleed
all 4 wheels again to get the remaining bubbles out and you should be in top
shape!

"Tom Waga" <twaga@NotForMail.com> wrote in message
news:B16sf.84875$2k.32255@pd7tw1no...[color=blue]
>I have "managed" to empty one chamber of master cylinder brake fluid
> container
> during brake job on the front passenger side. So, now I need to bleed the
> system.
>
> 1. Since only one chamber of reservoir was emptied will it be OK if I
> bleed
> only part of the system which was emptied in this case the driver back and
> next passenger front (in that order - I understand Corolla has a diagonal
> brake system) ?
>
> 2. Should I bleed emptied part of master cylinder by loosing the line at
> the
> mc or any air will be pushed out when brakes are bled, and what about
> front/rear distribution block?
>
> 3. Instead of using helper/pedal method can I use gravity method by
> opening
> the bleeding nipple with hose on the end submerged in bottle with fluid
> (it
> will take longer but not require helper)?
>
>
>[/color]

I did the job using gravity method. There was lots of bubbles flowing out
with fluid. I did not open the lines at the master.

After it looked OK I decided to re-check it with pedal/helper method. Front
line (the one I opened at the wheel cylinder) did not released any more
bubbles but the rear diagonal one had very fine bubbles coming out for some
time. I am not sure is it because with gravity flow the liquid velocity is
to slow to remove all the bubbles or I just cleared the line not long
enough?

I used the block of wood to restrict travel of the pedal while pumping
brakes and opening the nipples but I just wonder if that was necessary. The
reason is that although I haven never changed brake fluid till now (5 years
time) but every time I changed brake pads (every 50 000 KM) I had to press
brake pedal all the way to the floor to bring the pistons to the pads after
they were compressed (pistons). Wouldn't that remove any gunk from inside of
the master cylinder?



": )" <none@none.net> wrote in message
news:CC6sf.6458$pE4.5841@tornado.socal.rr.com...
| gravity bleeding will work fine and it's best to bleed the whole system at
| the wheels. you shouldn't have to crack the lines connected to the brake
| master. I've done it many times with all the brake jobs done in the past.
| just remember to keep checking the master cylinder reservoir to make sure
is
| isn't going dry again or you're doing double work. work 1 wheel at a
time,
| cracking the bleeder screw and let the fluid drip. let it drip until
clean
| fluid emerges. also, keep the cap on the master loose or off so a vacuum
| isn't created as the fluid is drained. note: since one chamber of the
| master went dry, as the fluid is dripping from the first bleeder screw
| you've opened. tap the end of the master cylinder with a hammer to help
| dislodge any air bubbles trapped inside the master. just don't pound on
it
| since it is a cast aluminum body. once you've bled all 4 wheels, pump the
| brake pedal a few times, making sure not to bottom out the pedal (or you
| risk killing the master cylinder). this will cause the caliper pistons
| caliper pistons to move back into their proper position if they were
| compressed while changing pads. it will also help to work loose any air
| bubbles that may have remained trapped in the brake system. now, just
bleed
| all 4 wheels again to get the remaining bubbles out and you should be in
top
| shape!
|
| "Tom Waga" <twaga@NotForMail.com> wrote in message
| news:B16sf.84875$2k.32255@pd7tw1no...
| >I have "managed" to empty one chamber of master cylinder brake fluid
| > container
| > during brake job on the front passenger side. So, now I need to bleed
the
| > system.
| >
| > 1. Since only one chamber of reservoir was emptied will it be OK if I
| > bleed
| > only part of the system which was emptied in this case the driver back
and
| > next passenger front (in that order - I understand Corolla has a
diagonal
| > brake system) ?
| >
| > 2. Should I bleed emptied part of master cylinder by loosing the line at
| > the
| > mc or any air will be pushed out when brakes are bled, and what about
| > front/rear distribution block?
| >
| > 3. Instead of using helper/pedal method can I use gravity method by
| > opening
| > the bleeding nipple with hose on the end submerged in bottle with fluid
| > (it
| > will take longer but not require helper)?
| >
| >
| >
|
|

you were very lucky in the past when the brake pedal was bottomed out.
during the course of normal driving/braking, each time the brake pedal is
depressed, the piston in the master cylinder only travels a certain distance
due to the resistance caused by the pads and shoes doing their job (making
contact with the rotor & drum). since the master cylinder piston rod/seal
cups continually travel over a specific area due to the hydraulic pressure,
gunk/junk often builds up in the area not cleared by the seal. in turn,
pitting usually occurs in aluminum bodied masters where the gunk/junk
settles (steel bodied masters usually aren't affect as often). when the
seal travels over the area with the gunk/junk, the seal can be damaged.
also, the gunk/junk usually causes pitting which is visible when the area is
cleared. often the damaged seal isn't noticed under heavy braking because
the seal expands rapidly, pushing on the brake fluid. the damage seal
usually shows itself in heavy traffic or gentle braking, where the seals
aren't so expanded and allow brake fluid to by-pass the seal, which will
cause the pedal to start going to the floor. at that point, most people
panic and push the pedal hard which usually causes sufficient hydraulic
pressure to fully expand the seal and stop the vehicle. then when the foot
pressure is let up, the process happens all over again. many times the
driver will pump the pedal and it will seem hard and firm again and they
can't figure out what's going on.

as far as your question about the junk in the caliper being dislodged and
flushed out when the bleeder is opened...sorry, it wont happen. there may
be some loose junk drifting around in the fluid and that type of junk will
come out when bleeding the brakes, but there's more junk and varnish that
remains stuck to the inside of the caliper. the caliper piston rides on the
caliper piston seal and doesn't make contact with the caliper body, except
for the bottom of the piston when it is bottomed out in the caliper. all
that crap in the caliper body will cause pitting, which isn't much of a
problem as long as it doesn't build up by the seal grove. when the junk
does build up by the seal grove, it affects the way the seal operates and
will often lead to sticking pistons and rapid wear of the brake pads, not to
mention pulling when braking and brake drag.

FYI...the gunk/junk also builds up in the wheel cylinders and will also
cause corroding and pitting. it usually manifests its self by leaking in
the brake drum. you can do a simple check when checking the rear brakes
(wheels/drums off). just use a small screw driver or pinch the dust boot on
the wheel cylinder to lift a small area. if very little fluid leaks out,
it's ok (normal weeping). if it gushes out, it's a sign the wheel cylinder
is starting to go and it may not be too long before it starts to actually
leak, soaking the rear brakes.

"Tom Waga" <twaga@NotForMail.com> wrote in message
news:F8psf.201126$ki.81970@pd7tw2no...[color=blue]
>I did the job using gravity method. There was lots of bubbles flowing out
> with fluid. I did not open the lines at the master.
>
> After it looked OK I decided to re-check it with pedal/helper method.
> Front
> line (the one I opened at the wheel cylinder) did not released any more
> bubbles but the rear diagonal one had very fine bubbles coming out for
> some
> time. I am not sure is it because with gravity flow the liquid velocity is
> to slow to remove all the bubbles or I just cleared the line not long
> enough?
>
> I used the block of wood to restrict travel of the pedal while pumping
> brakes and opening the nipples but I just wonder if that was necessary.
> The
> reason is that although I haven never changed brake fluid till now (5
> years
> time) but every time I changed brake pads (every 50 000 KM) I had to press
> brake pedal all the way to the floor to bring the pistons to the pads
> after
> they were compressed (pistons). Wouldn't that remove any gunk from inside
> of
> the master cylinder?
>
>
>
> ": )" <none@none.net> wrote in message
> news:CC6sf.6458$pE4.5841@tornado.socal.rr.com...
> | gravity bleeding will work fine and it's best to bleed the whole system
> at
> | the wheels. you shouldn't have to crack the lines connected to the
> brake
> | master. I've done it many times with all the brake jobs done in the
> past.
> | just remember to keep checking the master cylinder reservoir to make
> sure
> is
> | isn't going dry again or you're doing double work. work 1 wheel at a
> time,
> | cracking the bleeder screw and let the fluid drip. let it drip until
> clean
> | fluid emerges. also, keep the cap on the master loose or off so a
> vacuum
> | isn't created as the fluid is drained. note: since one chamber of the
> | master went dry, as the fluid is dripping from the first bleeder screw
> | you've opened. tap the end of the master cylinder with a hammer to help
> | dislodge any air bubbles trapped inside the master. just don't pound on
> it
> | since it is a cast aluminum body. once you've bled all 4 wheels, pump
> the
> | brake pedal a few times, making sure not to bottom out the pedal (or you
> | risk killing the master cylinder). this will cause the caliper pistons
> | caliper pistons to move back into their proper position if they were
> | compressed while changing pads. it will also help to work loose any air
> | bubbles that may have remained trapped in the brake system. now, just
> bleed
> | all 4 wheels again to get the remaining bubbles out and you should be in
> top
> | shape!
> |
> | "Tom Waga" <twaga@NotForMail.com> wrote in message
> | news:B16sf.84875$2k.32255@pd7tw1no...
> | >I have "managed" to empty one chamber of master cylinder brake fluid
> | > container
> | > during brake job on the front passenger side. So, now I need to bleed
> the
> | > system.
> | >
> | > 1. Since only one chamber of reservoir was emptied will it be OK if I
> | > bleed
> | > only part of the system which was emptied in this case the driver back
> and
> | > next passenger front (in that order - I understand Corolla has a
> diagonal
> | > brake system) ?
> | >
> | > 2. Should I bleed emptied part of master cylinder by loosing the line
> at
> | > the
> | > mc or any air will be pushed out when brakes are bled, and what about
> | > front/rear distribution block?
> | >
> | > 3. Instead of using helper/pedal method can I use gravity method by
> | > opening
> | > the bleeding nipple with hose on the end submerged in bottle with
> fluid
> | > (it
> | > will take longer but not require helper)?
> | >
> | >
> | >
> |
> |
>
>[/color]

forgot to mention, the critical sealing surface in the caliper (besides
having a clean/clear piston seal grove) is the caliper piston. the piston
can have some very minor pitting, as long at the pitting isn't large enough
to cause fluid to by-pass the seal, but eventually it will need to be
replaced and will only save you money in the short term. a pitted or badly
scored caliper piston should be replaced when doing the brake job the first
time. not a few months later.

as for my back ground, I worked as a brake tech many years ago, on all makes
and types of passenger cars & trucks. personally (my opinion only), I don't
care for preloaded calipers since I usually ended up rebuilding them because
they weren't done properly at the rebuilder (in most cases, I found junk
left in the caliper seal grove which would cause the seal to hang up). did
it all from complete brake jobs (including overhauls/rebuilds), machining
drums and rotors off the vehicle and machining rotors on vehicles (my
preference since I'd try to get the run-out to .000). if the tech could and
would take the time to do the job right the 1st time, the chance of the
vehicle returning for a problem would be minimal until the lining needed
changing again. of course, the driver would have to do their part and not
abuse their brakes. I had a lady once who returned the day after a complete
brake job. she complained of an odd smell and the car was hard to stop.
once the wheels were pulled, the problem was obvious. the rotors were
literly blue with hard spots. turned out, the lady wanted to help break-in
her new brakes so she rode the brake pedal all the way home (about 12
miles). fortunately the rotors could be resurfaced within toleranced and
the hard spots came out. brake linings were replaced and the driver
instructed on what not to do. don't remember ever hearing from her again
after that.

What would be a time period needed to deposit dangerous enough gunk layer
on the inside of master cylinder (approx)?


": )" <none@none.net> wrote in message
news:3Xqsf.8180$ka.4965@tornado.socal.rr.com...
| you were very lucky in the past when the brake pedal was bottomed out.
| during the course of normal driving/braking, each time the brake pedal is
| depressed, the piston in the master cylinder only travels a certain
distance
| due to the resistance caused by the pads and shoes doing their job (making
| contact with the rotor & drum). since the master cylinder piston rod/seal
| cups continually travel over a specific area due to the hydraulic
pressure,
| gunk/junk often builds up in the area not cleared by the seal. in turn,
| pitting usually occurs in aluminum bodied masters where the gunk/junk
| settles (steel bodied masters usually aren't affect as often). when the
| seal travels over the area with the gunk/junk, the seal can be damaged.
| also, the gunk/junk usually causes pitting which is visible when the area
is
| cleared. often the damaged seal isn't noticed under heavy braking because
| the seal expands rapidly, pushing on the brake fluid. the damage seal
| usually shows itself in heavy traffic or gentle braking, where the seals
| aren't so expanded and allow brake fluid to by-pass the seal, which will
| cause the pedal to start going to the floor. at that point, most people
| panic and push the pedal hard which usually causes sufficient hydraulic
| pressure to fully expand the seal and stop the vehicle. then when the
foot
| pressure is let up, the process happens all over again. many times the
| driver will pump the pedal and it will seem hard and firm again and they
| can't figure out what's going on.
|
| as far as your question about the junk in the caliper being dislodged and
| flushed out when the bleeder is opened...sorry, it wont happen. there may
| be some loose junk drifting around in the fluid and that type of junk will
| come out when bleeding the brakes, but there's more junk and varnish that
| remains stuck to the inside of the caliper. the caliper piston rides on
the
| caliper piston seal and doesn't make contact with the caliper body, except
| for the bottom of the piston when it is bottomed out in the caliper. all
| that crap in the caliper body will cause pitting, which isn't much of a
| problem as long as it doesn't build up by the seal grove. when the junk
| does build up by the seal grove, it affects the way the seal operates and
| will often lead to sticking pistons and rapid wear of the brake pads, not
to
| mention pulling when braking and brake drag.
|
| FYI...the gunk/junk also builds up in the wheel cylinders and will also
| cause corroding and pitting. it usually manifests its self by leaking in
| the brake drum. you can do a simple check when checking the rear brakes
| (wheels/drums off). just use a small screw driver or pinch the dust boot
on
| the wheel cylinder to lift a small area. if very little fluid leaks out,
| it's ok (normal weeping). if it gushes out, it's a sign the wheel
cylinder
| is starting to go and it may not be too long before it starts to actually
| leak, soaking the rear brakes.
|
| "Tom Waga" <twaga@NotForMail.com> wrote in message
| news:F8psf.201126$ki.81970@pd7tw2no...
| >I did the job using gravity method. There was lots of bubbles flowing out
| > with fluid. I did not open the lines at the master.
| >
| > After it looked OK I decided to re-check it with pedal/helper method.
| > Front
| > line (the one I opened at the wheel cylinder) did not released any more
| > bubbles but the rear diagonal one had very fine bubbles coming out for
| > some
| > time. I am not sure is it because with gravity flow the liquid velocity
is
| > to slow to remove all the bubbles or I just cleared the line not long
| > enough?
| >
| > I used the block of wood to restrict travel of the pedal while pumping
| > brakes and opening the nipples but I just wonder if that was necessary.
| > The
| > reason is that although I haven never changed brake fluid till now (5
| > years
| > time) but every time I changed brake pads (every 50 000 KM) I had to
press
| > brake pedal all the way to the floor to bring the pistons to the pads
| > after
| > they were compressed (pistons). Wouldn't that remove any gunk from
inside
| > of
| > the master cylinder?
| >
| >
| >
| > ": )" <none@none.net> wrote in message
| > news:CC6sf.6458$pE4.5841@tornado.socal.rr.com...
| > | gravity bleeding will work fine and it's best to bleed the whole
system
| > at
| > | the wheels. you shouldn't have to crack the lines connected to the
| > brake
| > | master. I've done it many times with all the brake jobs done in the
| > past.
| > | just remember to keep checking the master cylinder reservoir to make
| > sure
| > is
| > | isn't going dry again or you're doing double work. work 1 wheel at a
| > time,
| > | cracking the bleeder screw and let the fluid drip. let it drip until
| > clean
| > | fluid emerges. also, keep the cap on the master loose or off so a
| > vacuum
| > | isn't created as the fluid is drained. note: since one chamber of
the
| > | master went dry, as the fluid is dripping from the first bleeder screw
| > | you've opened. tap the end of the master cylinder with a hammer to
help
| > | dislodge any air bubbles trapped inside the master. just don't pound
on
| > it
| > | since it is a cast aluminum body. once you've bled all 4 wheels, pump
| > the
| > | brake pedal a few times, making sure not to bottom out the pedal (or
you
| > | risk killing the master cylinder). this will cause the caliper
pistons
| > | caliper pistons to move back into their proper position if they were
| > | compressed while changing pads. it will also help to work loose any
air
| > | bubbles that may have remained trapped in the brake system. now, just
| > bleed
| > | all 4 wheels again to get the remaining bubbles out and you should be
in
| > top
| > | shape!
| > |
| > | "Tom Waga" <twaga@NotForMail.com> wrote in message
| > | news:B16sf.84875$2k.32255@pd7tw1no...
| > | >I have "managed" to empty one chamber of master cylinder brake fluid
| > | > container
| > | > during brake job on the front passenger side. So, now I need to
bleed
| > the
| > | > system.
| > | >
| > | > 1. Since only one chamber of reservoir was emptied will it be OK if
I
| > | > bleed
| > | > only part of the system which was emptied in this case the driver
back
| > and
| > | > next passenger front (in that order - I understand Corolla has a
| > diagonal
| > | > brake system) ?
| > | >
| > | > 2. Should I bleed emptied part of master cylinder by loosing the
line
| > at
| > | > the
| > | > mc or any air will be pushed out when brakes are bled, and what
about
| > | > front/rear distribution block?
| > | >
| > | > 3. Instead of using helper/pedal method can I use gravity method by
| > | > opening
| > | > the bleeding nipple with hose on the end submerged in bottle with
| > fluid
| > | > (it
| > | > will take longer but not require helper)?
| > | >
| > | >
| > | >
| > |
| > |
| >
| >
|
|

poorly maintained vehicles, possibly 5 years, or less, dependant on driving
conditions (lots of water crossing or driving with water up to the axles).
well maintained vehicles, 7+ years or longer.

gunk build-up would be dependant on how often brake fluid is flushed through
the system and the moisture in the environment. brake fluid is hydroscopic,
meaning it absorbs moisture. the moisture can be absorbed through the
rubber brake hoses, especially if they're cracked on the outer surface, some
moisture is absorbed when the cap from the master is removed for a prolonged
period of time (like all day), and moisture is absorbed even through the
seals in the calipers and wheel cylinders and even through the rubber seal
for the master cylinder cap. (many people aren't even aware there are
rubber brake hoses some where in the system for the rear brakes, since they
aren't easily visible until the vehicle is lifted). if you live in a drier
climate and flush the brake fluid annually, gunk build-up should be
minimal. a good indicator is the color of the old fluid being flushed out.
at its worst, the color is a dark amber meaning there's a strong probability
that gunk and varnish is accumulating some where within the brake system.
if the fluid being flushed out is a light amber to clear, you probably don't
have much to worry about.

"Tom Waga" <twaga@NotForMail.com> wrote in message
news:fpHsf.206334$ki.161913@pd7tw2no...[color=blue]
> What would be a time period needed to deposit dangerous enough gunk layer
> on the inside of master cylinder (approx)?
>
>
> ": )" <none@none.net> wrote in message
> news:3Xqsf.8180$ka.4965@tornado.socal.rr.com...
> | you were very lucky in the past when the brake pedal was bottomed out.
> | during the course of normal driving/braking, each time the brake pedal
> is
> | depressed, the piston in the master cylinder only travels a certain
> distance
> | due to the resistance caused by the pads and shoes doing their job
> (making
> | contact with the rotor & drum). since the master cylinder piston
> rod/seal
> | cups continually travel over a specific area due to the hydraulic
> pressure,
> | gunk/junk often builds up in the area not cleared by the seal. in turn,
> | pitting usually occurs in aluminum bodied masters where the gunk/junk
> | settles (steel bodied masters usually aren't affect as often). when the
> | seal travels over the area with the gunk/junk, the seal can be damaged.
> | also, the gunk/junk usually causes pitting which is visible when the
> area
> is
> | cleared. often the damaged seal isn't noticed under heavy braking
> because
> | the seal expands rapidly, pushing on the brake fluid. the damage seal
> | usually shows itself in heavy traffic or gentle braking, where the seals
> | aren't so expanded and allow brake fluid to by-pass the seal, which will
> | cause the pedal to start going to the floor. at that point, most people
> | panic and push the pedal hard which usually causes sufficient hydraulic
> | pressure to fully expand the seal and stop the vehicle. then when the
> foot
> | pressure is let up, the process happens all over again. many times the
> | driver will pump the pedal and it will seem hard and firm again and they
> | can't figure out what's going on.
> |
> | as far as your question about the junk in the caliper being dislodged
> and
> | flushed out when the bleeder is opened...sorry, it wont happen. there
> may
> | be some loose junk drifting around in the fluid and that type of junk
> will
> | come out when bleeding the brakes, but there's more junk and varnish
> that
> | remains stuck to the inside of the caliper. the caliper piston rides on
> the
> | caliper piston seal and doesn't make contact with the caliper body,
> except
> | for the bottom of the piston when it is bottomed out in the caliper.
> all
> | that crap in the caliper body will cause pitting, which isn't much of a
> | problem as long as it doesn't build up by the seal grove. when the junk
> | does build up by the seal grove, it affects the way the seal operates
> and
> | will often lead to sticking pistons and rapid wear of the brake pads,
> not
> to
> | mention pulling when braking and brake drag.
> |
> | FYI...the gunk/junk also builds up in the wheel cylinders and will also
> | cause corroding and pitting. it usually manifests its self by leaking
> in
> | the brake drum. you can do a simple check when checking the rear brakes
> | (wheels/drums off). just use a small screw driver or pinch the dust
> boot
> on
> | the wheel cylinder to lift a small area. if very little fluid leaks
> out,
> | it's ok (normal weeping). if it gushes out, it's a sign the wheel
> cylinder
> | is starting to go and it may not be too long before it starts to
> actually
> | leak, soaking the rear brakes.
> |
> | "Tom Waga" <twaga@NotForMail.com> wrote in message
> | news:F8psf.201126$ki.81970@pd7tw2no...
> | >I did the job using gravity method. There was lots of bubbles flowing
> out
> | > with fluid. I did not open the lines at the master.
> | >
> | > After it looked OK I decided to re-check it with pedal/helper method.
> | > Front
> | > line (the one I opened at the wheel cylinder) did not released any
> more
> | > bubbles but the rear diagonal one had very fine bubbles coming out for
> | > some
> | > time. I am not sure is it because with gravity flow the liquid
> velocity
> is
> | > to slow to remove all the bubbles or I just cleared the line not long
> | > enough?
> | >
> | > I used the block of wood to restrict travel of the pedal while pumping
> | > brakes and opening the nipples but I just wonder if that was
> necessary.
> | > The
> | > reason is that although I haven never changed brake fluid till now (5
> | > years
> | > time) but every time I changed brake pads (every 50 000 KM) I had to
> press
> | > brake pedal all the way to the floor to bring the pistons to the pads
> | > after
> | > they were compressed (pistons). Wouldn't that remove any gunk from
> inside
> | > of
> | > the master cylinder?
> | >
> | >
> | >
> | > ": )" <none@none.net> wrote in message
> | > news:CC6sf.6458$pE4.5841@tornado.socal.rr.com...
> | > | gravity bleeding will work fine and it's best to bleed the whole
> system
> | > at
> | > | the wheels. you shouldn't have to crack the lines connected to the
> | > brake
> | > | master. I've done it many times with all the brake jobs done in the
> | > past.
> | > | just remember to keep checking the master cylinder reservoir to make
> | > sure
> | > is
> | > | isn't going dry again or you're doing double work. work 1 wheel at
> a
> | > time,
> | > | cracking the bleeder screw and let the fluid drip. let it drip
> until
> | > clean
> | > | fluid emerges. also, keep the cap on the master loose or off so a
> | > vacuum
> | > | isn't created as the fluid is drained. note: since one chamber of
> the
> | > | master went dry, as the fluid is dripping from the first bleeder
> screw
> | > | you've opened. tap the end of the master cylinder with a hammer to
> help
> | > | dislodge any air bubbles trapped inside the master. just don't
> pound
> on
> | > it
> | > | since it is a cast aluminum body. once you've bled all 4 wheels,
> pump
> | > the
> | > | brake pedal a few times, making sure not to bottom out the pedal (or
> you
> | > | risk killing the master cylinder). this will cause the caliper
> pistons
> | > | caliper pistons to move back into their proper position if they were
> | > | compressed while changing pads. it will also help to work loose any
> air
> | > | bubbles that may have remained trapped in the brake system. now,
> just
> | > bleed
> | > | all 4 wheels again to get the remaining bubbles out and you should
> be
> in
> | > top
> | > | shape!
> | > |
> | > | "Tom Waga" <twaga@NotForMail.com> wrote in message
> | > | news:B16sf.84875$2k.32255@pd7tw1no...
> | > | >I have "managed" to empty one chamber of master cylinder brake
> fluid
> | > | > container
> | > | > during brake job on the front passenger side. So, now I need to
> bleed
> | > the
> | > | > system.
> | > | >
> | > | > 1. Since only one chamber of reservoir was emptied will it be OK
> if
> I
> | > | > bleed
> | > | > only part of the system which was emptied in this case the driver
> back
> | > and
> | > | > next passenger front (in that order - I understand Corolla has a
> | > diagonal
> | > | > brake system) ?
> | > | >
> | > | > 2. Should I bleed emptied part of master cylinder by loosing the
> line
> | > at
> | > | > the
> | > | > mc or any air will be pushed out when brakes are bled, and what
> about
> | > | > front/rear distribution block?
> | > | >
> | > | > 3. Instead of using helper/pedal method can I use gravity method
> by
> | > | > opening
> | > | > the bleeding nipple with hose on the end submerged in bottle with
> | > fluid
> | > | > (it
> | > | > will take longer but not require helper)?
> | > | >
> | > | >
> | > | >
> | > |
> | > |
> | >
> | >
> |
> |
>
>[/color]

One would wonder why isn't there a scheduled brake fluid replacement/brake
line flush procedure included in the service manual since it can induce such
a negative effect on the master cylinder and brake lines?

": )" <none@none.net> wrote in message
news:sHLsf.8350$ka.2007@tornado.socal.rr.com...
| poorly maintained vehicles, possibly 5 years, or less, dependant on
driving
| conditions (lots of water crossing or driving with water up to the axles).
| well maintained vehicles, 7+ years or longer.
|
| gunk build-up would be dependant on how often brake fluid is flushed
through
| the system and the moisture in the environment. brake fluid is
hydroscopic,
| meaning it absorbs moisture. the moisture can be absorbed through the
| rubber brake hoses, especially if they're cracked on the outer surface,
some
| moisture is absorbed when the cap from the master is removed for a
prolonged
| period of time (like all day), and moisture is absorbed even through the
| seals in the calipers and wheel cylinders and even through the rubber seal
| for the master cylinder cap. (many people aren't even aware there are
| rubber brake hoses some where in the system for the rear brakes, since
they
| aren't easily visible until the vehicle is lifted). if you live in a
drier
| climate and flush the brake fluid annually, gunk build-up should be
| minimal. a good indicator is the color of the old fluid being flushed
out.
| at its worst, the color is a dark amber meaning there's a strong
probability
| that gunk and varnish is accumulating some where within the brake system.
| if the fluid being flushed out is a light amber to clear, you probably
don't
| have much to worry about.
|
| "Tom Waga" <twaga@NotForMail.com> wrote in message
| news:fpHsf.206334$ki.161913@pd7tw2no...
| > What would be a time period needed to deposit dangerous enough gunk
layer
| > on the inside of master cylinder (approx)?
| >
| >
| > ": )" <none@none.net> wrote in message
| > news:3Xqsf.8180$ka.4965@tornado.socal.rr.com...
| > | you were very lucky in the past when the brake pedal was bottomed out.
| > | during the course of normal driving/braking, each time the brake pedal
| > is
| > | depressed, the piston in the master cylinder only travels a certain
| > distance
| > | due to the resistance caused by the pads and shoes doing their job
| > (making
| > | contact with the rotor & drum). since the master cylinder piston
| > rod/seal
| > | cups continually travel over a specific area due to the hydraulic
| > pressure,
| > | gunk/junk often builds up in the area not cleared by the seal. in
turn,
| > | pitting usually occurs in aluminum bodied masters where the gunk/junk
| > | settles (steel bodied masters usually aren't affect as often). when
the
| > | seal travels over the area with the gunk/junk, the seal can be
damaged.
| > | also, the gunk/junk usually causes pitting which is visible when the
| > area
| > is
| > | cleared. often the damaged seal isn't noticed under heavy braking
| > because
| > | the seal expands rapidly, pushing on the brake fluid. the damage seal
| > | usually shows itself in heavy traffic or gentle braking, where the
seals
| > | aren't so expanded and allow brake fluid to by-pass the seal, which
will
| > | cause the pedal to start going to the floor. at that point, most
people
| > | panic and push the pedal hard which usually causes sufficient
hydraulic
| > | pressure to fully expand the seal and stop the vehicle. then when the
| > foot
| > | pressure is let up, the process happens all over again. many times
the
| > | driver will pump the pedal and it will seem hard and firm again and
they
| > | can't figure out what's going on.
| > |
| > | as far as your question about the junk in the caliper being dislodged
| > and
| > | flushed out when the bleeder is opened...sorry, it wont happen. there
| > may
| > | be some loose junk drifting around in the fluid and that type of junk
| > will
| > | come out when bleeding the brakes, but there's more junk and varnish
| > that
| > | remains stuck to the inside of the caliper. the caliper piston rides
on
| > the
| > | caliper piston seal and doesn't make contact with the caliper body,
| > except
| > | for the bottom of the piston when it is bottomed out in the caliper.
| > all
| > | that crap in the caliper body will cause pitting, which isn't much of
a
| > | problem as long as it doesn't build up by the seal grove. when the
junk
| > | does build up by the seal grove, it affects the way the seal operates
| > and
| > | will often lead to sticking pistons and rapid wear of the brake pads,
| > not
| > to
| > | mention pulling when braking and brake drag.
| > |
| > | FYI...the gunk/junk also builds up in the wheel cylinders and will
also
| > | cause corroding and pitting. it usually manifests its self by leaking
| > in
| > | the brake drum. you can do a simple check when checking the rear
brakes
| > | (wheels/drums off). just use a small screw driver or pinch the dust
| > boot
| > on
| > | the wheel cylinder to lift a small area. if very little fluid leaks
| > out,
| > | it's ok (normal weeping). if it gushes out, it's a sign the wheel
| > cylinder
| > | is starting to go and it may not be too long before it starts to
| > actually
| > | leak, soaking the rear brakes.
| > |
| > | "Tom Waga" <twaga@NotForMail.com> wrote in message
| > | news:F8psf.201126$ki.81970@pd7tw2no...
| > | >I did the job using gravity method. There was lots of bubbles flowing
| > out
| > | > with fluid. I did not open the lines at the master.
| > | >
| > | > After it looked OK I decided to re-check it with pedal/helper
method.
| > | > Front
| > | > line (the one I opened at the wheel cylinder) did not released any
| > more
| > | > bubbles but the rear diagonal one had very fine bubbles coming out
for
| > | > some
| > | > time. I am not sure is it because with gravity flow the liquid
| > velocity
| > is
| > | > to slow to remove all the bubbles or I just cleared the line not
long
| > | > enough?
| > | >
| > | > I used the block of wood to restrict travel of the pedal while
pumping
| > | > brakes and opening the nipples but I just wonder if that was
| > necessary.
| > | > The
| > | > reason is that although I haven never changed brake fluid till now
(5
| > | > years
| > | > time) but every time I changed brake pads (every 50 000 KM) I had to
| > press
| > | > brake pedal all the way to the floor to bring the pistons to the
pads
| > | > after
| > | > they were compressed (pistons). Wouldn't that remove any gunk from
| > inside
| > | > of
| > | > the master cylinder?
| > | >
| > | >
| > | >
| > | > ": )" <none@none.net> wrote in message
| > | > news:CC6sf.6458$pE4.5841@tornado.socal.rr.com...
| > | > | gravity bleeding will work fine and it's best to bleed the whole
| > system
| > | > at
| > | > | the wheels. you shouldn't have to crack the lines connected to
the
| > | > brake
| > | > | master. I've done it many times with all the brake jobs done in
the
| > | > past.
| > | > | just remember to keep checking the master cylinder reservoir to
make
| > | > sure
| > | > is
| > | > | isn't going dry again or you're doing double work. work 1 wheel
at
| > a
| > | > time,
| > | > | cracking the bleeder screw and let the fluid drip. let it drip
| > until
| > | > clean
| > | > | fluid emerges. also, keep the cap on the master loose or off so a
| > | > vacuum
| > | > | isn't created as the fluid is drained. note: since one chamber
of
| > the
| > | > | master went dry, as the fluid is dripping from the first bleeder
| > screw
| > | > | you've opened. tap the end of the master cylinder with a hammer to
| > help
| > | > | dislodge any air bubbles trapped inside the master. just don't
| > pound
| > on
| > | > it
| > | > | since it is a cast aluminum body. once you've bled all 4 wheels,
| > pump
| > | > the
| > | > | brake pedal a few times, making sure not to bottom out the pedal
(or
| > you
| > | > | risk killing the master cylinder). this will cause the caliper
| > pistons
| > | > | caliper pistons to move back into their proper position if they
were
| > | > | compressed while changing pads. it will also help to work loose
any
| > air
| > | > | bubbles that may have remained trapped in the brake system. now,
| > just
| > | > bleed
| > | > | all 4 wheels again to get the remaining bubbles out and you should
| > be
| > in
| > | > top
| > | > | shape!
| > | > |
| > | > | "Tom Waga" <twaga@NotForMail.com> wrote in message
| > | > | news:B16sf.84875$2k.32255@pd7tw1no...
| > | > | >I have "managed" to empty one chamber of master cylinder brake
| > fluid
| > | > | > container
| > | > | > during brake job on the front passenger side. So, now I need to
| > bleed
| > | > the
| > | > | > system.
| > | > | >
| > | > | > 1. Since only one chamber of reservoir was emptied will it be OK
| > if
| > I
| > | > | > bleed
| > | > | > only part of the system which was emptied in this case the
driver
| > back
| > | > and
| > | > | > next passenger front (in that order - I understand Corolla has a
| > | > diagonal
| > | > | > brake system) ?
| > | > | >
| > | > | > 2. Should I bleed emptied part of master cylinder by loosing the
| > line
| > | > at
| > | > | > the
| > | > | > mc or any air will be pushed out when brakes are bled, and what
| > about
| > | > | > front/rear distribution block?
| > | > | >
| > | > | > 3. Instead of using helper/pedal method can I use gravity method
| > by
| > | > | > opening
| > | > | > the bleeding nipple with hose on the end submerged in bottle
with
| > | > fluid
| > | > | > (it
| > | > | > will take longer but not require helper)?
| > | > | >
| > | > | >
| > | > | >
| > | > |
| > | > |
| > | >
| > | >
| > |
| > |
| >
| >
|
|

more than likely it comes down to the almighty $. if vehicle owners kept on
top of everything, then parts wouldn't wear as fast and parts wouldn't need
replacing or rebuilding as often. allows them to charge a fair amount for
something that isn't really difficult to do. I remember labor charges for a
complete brake job for an American car (rebuilding calipers/wheel cylinders,
resurfacing rotors & drums and bleeding the hydraulic system, installing new
pads/shoes) costing $120 + parts charges. I'd make about $2.40 off the
labor charge (plus my hourly wage) and it took any where from 1/2 hour to 45
minutes to do the actual work. you do the math for an 8 hour day. that's
why I got out of that line of work. busting your rear for peanuts while the
shop makes the big bucks.

BTW...
the shop also used to charge $160 to do only the front brakes (labor only)
on a front wheel drive car without hubless rotors (older imports). even
though the rotors were machined with an on-the-car lathe. usually the
machining would take about 1/2 hour and the calipers were rebuilt while the
rotors were being cut.

"Tom Waga" <twaga@NotForMail.com> wrote in message
news:YxMsf.207603$ki.126237@pd7tw2no...[color=blue]
> One would wonder why isn't there a scheduled brake fluid replacement/brake
> line flush procedure included in the service manual since it can induce
> such
> a negative effect on the master cylinder and brake lines?
>
> ": )" <none@none.net> wrote in message
> news:sHLsf.8350$ka.2007@tornado.socal.rr.com...
> | poorly maintained vehicles, possibly 5 years, or less, dependant on
> driving
> | conditions (lots of water crossing or driving with water up to the
> axles).
> | well maintained vehicles, 7+ years or longer.
> |
> | gunk build-up would be dependant on how often brake fluid is flushed
> through
> | the system and the moisture in the environment. brake fluid is
> hydroscopic,
> | meaning it absorbs moisture. the moisture can be absorbed through the
> | rubber brake hoses, especially if they're cracked on the outer surface,
> some
> | moisture is absorbed when the cap from the master is removed for a
> prolonged
> | period of time (like all day), and moisture is absorbed even through the
> | seals in the calipers and wheel cylinders and even through the rubber
> seal
> | for the master cylinder cap. (many people aren't even aware there are
> | rubber brake hoses some where in the system for the rear brakes, since
> they
> | aren't easily visible until the vehicle is lifted). if you live in a
> drier
> | climate and flush the brake fluid annually, gunk build-up should be
> | minimal. a good indicator is the color of the old fluid being flushed
> out.
> | at its worst, the color is a dark amber meaning there's a strong
> probability
> | that gunk and varnish is accumulating some where within the brake
> system.
> | if the fluid being flushed out is a light amber to clear, you probably
> don't
> | have much to worry about.
> |
> | "Tom Waga" <twaga@NotForMail.com> wrote in message
> | news:fpHsf.206334$ki.161913@pd7tw2no...
> | > What would be a time period needed to deposit dangerous enough gunk
> layer
> | > on the inside of master cylinder (approx)?
> | >
> | >
> | > ": )" <none@none.net> wrote in message
> | > news:3Xqsf.8180$ka.4965@tornado.socal.rr.com...
> | > | you were very lucky in the past when the brake pedal was bottomed
> out.
> | > | during the course of normal driving/braking, each time the brake
> pedal
> | > is
> | > | depressed, the piston in the master cylinder only travels a certain
> | > distance
> | > | due to the resistance caused by the pads and shoes doing their job
> | > (making
> | > | contact with the rotor & drum). since the master cylinder piston
> | > rod/seal
> | > | cups continually travel over a specific area due to the hydraulic
> | > pressure,
> | > | gunk/junk often builds up in the area not cleared by the seal. in
> turn,
> | > | pitting usually occurs in aluminum bodied masters where the
> gunk/junk
> | > | settles (steel bodied masters usually aren't affect as often). when
> the
> | > | seal travels over the area with the gunk/junk, the seal can be
> damaged.
> | > | also, the gunk/junk usually causes pitting which is visible when the
> | > area
> | > is
> | > | cleared. often the damaged seal isn't noticed under heavy braking
> | > because
> | > | the seal expands rapidly, pushing on the brake fluid. the damage
> seal
> | > | usually shows itself in heavy traffic or gentle braking, where the
> seals
> | > | aren't so expanded and allow brake fluid to by-pass the seal, which
> will
> | > | cause the pedal to start going to the floor. at that point, most
> people
> | > | panic and push the pedal hard which usually causes sufficient
> hydraulic
> | > | pressure to fully expand the seal and stop the vehicle. then when
> the
> | > foot
> | > | pressure is let up, the process happens all over again. many times
> the
> | > | driver will pump the pedal and it will seem hard and firm again and
> they
> | > | can't figure out what's going on.
> | > |
> | > | as far as your question about the junk in the caliper being
> dislodged
> | > and
> | > | flushed out when the bleeder is opened...sorry, it wont happen.
> there
> | > may
> | > | be some loose junk drifting around in the fluid and that type of
> junk
> | > will
> | > | come out when bleeding the brakes, but there's more junk and varnish
> | > that
> | > | remains stuck to the inside of the caliper. the caliper piston
> rides
> on
> | > the
> | > | caliper piston seal and doesn't make contact with the caliper body,
> | > except
> | > | for the bottom of the piston when it is bottomed out in the caliper.
> | > all
> | > | that crap in the caliper body will cause pitting, which isn't much
> of
> a
> | > | problem as long as it doesn't build up by the seal grove. when the
> junk
> | > | does build up by the seal grove, it affects the way the seal
> operates
> | > and
> | > | will often lead to sticking pistons and rapid wear of the brake
> pads,
> | > not
> | > to
> | > | mention pulling when braking and brake drag.
> | > |
> | > | FYI...the gunk/junk also builds up in the wheel cylinders and will
> also
> | > | cause corroding and pitting. it usually manifests its self by
> leaking
> | > in
> | > | the brake drum. you can do a simple check when checking the rear
> brakes
> | > | (wheels/drums off). just use a small screw driver or pinch the dust
> | > boot
> | > on
> | > | the wheel cylinder to lift a small area. if very little fluid leaks
> | > out,
> | > | it's ok (normal weeping). if it gushes out, it's a sign the wheel
> | > cylinder
> | > | is starting to go and it may not be too long before it starts to
> | > actually
> | > | leak, soaking the rear brakes.
> | > |
> | > | "Tom Waga" <twaga@NotForMail.com> wrote in message
> | > | news:F8psf.201126$ki.81970@pd7tw2no...
> | > | >I did the job using gravity method. There was lots of bubbles
> flowing
> | > out
> | > | > with fluid. I did not open the lines at the master.
> | > | >
> | > | > After it looked OK I decided to re-check it with pedal/helper
> method.
> | > | > Front
> | > | > line (the one I opened at the wheel cylinder) did not released any
> | > more
> | > | > bubbles but the rear diagonal one had very fine bubbles coming out
> for
> | > | > some
> | > | > time. I am not sure is it because with gravity flow the liquid
> | > velocity
> | > is
> | > | > to slow to remove all the bubbles or I just cleared the line not
> long
> | > | > enough?
> | > | >
> | > | > I used the block of wood to restrict travel of the pedal while
> pumping
> | > | > brakes and opening the nipples but I just wonder if that was
> | > necessary.
> | > | > The
> | > | > reason is that although I haven never changed brake fluid till now
> (5
> | > | > years
> | > | > time) but every time I changed brake pads (every 50 000 KM) I had
> to
> | > press
> | > | > brake pedal all the way to the floor to bring the pistons to the
> pads
> | > | > after
> | > | > they were compressed (pistons). Wouldn't that remove any gunk from
> | > inside
> | > | > of
> | > | > the master cylinder?
> | > | >
> | > | >
> | > | >
> | > | > ": )" <none@none.net> wrote in message
> | > | > news:CC6sf.6458$pE4.5841@tornado.socal.rr.com...
> | > | > | gravity bleeding will work fine and it's best to bleed the whole
> | > system
> | > | > at
> | > | > | the wheels. you shouldn't have to crack the lines connected to
> the
> | > | > brake
> | > | > | master. I've done it many times with all the brake jobs done in
> the
> | > | > past.
> | > | > | just remember to keep checking the master cylinder reservoir to
> make
> | > | > sure
> | > | > is
> | > | > | isn't going dry again or you're doing double work. work 1 wheel
> at
> | > a
> | > | > time,
> | > | > | cracking the bleeder screw and let the fluid drip. let it drip
> | > until
> | > | > clean
> | > | > | fluid emerges. also, keep the cap on the master loose or off so
> a
> | > | > vacuum
> | > | > | isn't created as the fluid is drained. note: since one chamber
> of
> | > the
> | > | > | master went dry, as the fluid is dripping from the first bleeder
> | > screw
> | > | > | you've opened. tap the end of the master cylinder with a hammer
> to
> | > help
> | > | > | dislodge any air bubbles trapped inside the master. just don't
> | > pound
> | > on
> | > | > it
> | > | > | since it is a cast aluminum body. once you've bled all 4
> wheels,
> | > pump
> | > | > the
> | > | > | brake pedal a few times, making sure not to bottom out the pedal
> (or
> | > you
> | > | > | risk killing the master cylinder). this will cause the caliper
> | > pistons
> | > | > | caliper pistons to move back into their proper position if they
> were
> | > | > | compressed while changing pads. it will also help to work loose
> any
> | > air
> | > | > | bubbles that may have remained trapped in the brake system.
> now,
> | > just
> | > | > bleed
> | > | > | all 4 wheels again to get the remaining bubbles out and you
> should
> | > be
> | > in
> | > | > top
> | > | > | shape!
> | > | > |
> | > | > | "Tom Waga" <twaga@NotForMail.com> wrote in message
> | > | > | news:B16sf.84875$2k.32255@pd7tw1no...
> | > | > | >I have "managed" to empty one chamber of master cylinder brake
> | > fluid
> | > | > | > container
> | > | > | > during brake job on the front passenger side. So, now I need
> to
> | > bleed
> | > | > the
> | > | > | > system.
> | > | > | >
> | > | > | > 1. Since only one chamber of reservoir was emptied will it be
> OK
> | > if
> | > I
> | > | > | > bleed
> | > | > | > only part of the system which was emptied in this case the
> driver
> | > back
> | > | > and
> | > | > | > next passenger front (in that order - I understand Corolla has
> a
> | > | > diagonal
> | > | > | > brake system) ?
> | > | > | >
> | > | > | > 2. Should I bleed emptied part of master cylinder by loosing
> the
> | > line
> | > | > at
> | > | > | > the
> | > | > | > mc or any air will be pushed out when brakes are bled, and
> what
> | > about
> | > | > | > front/rear distribution block?
> | > | > | >
> | > | > | > 3. Instead of using helper/pedal method can I use gravity
> method
> | > by
> | > | > | > opening
> | > | > | > the bleeding nipple with hose on the end submerged in bottle
> with
> | > | > fluid
> | > | > | > (it
> | > | > | > will take longer but not require helper)?
> | > | > | >
> | > | > | >
> | > | > | >
> | > | > |
> | > | > |
> | > | >
> | > | >
> | > |
> | > |
> | >
> | >
> |
> |
>
>[/color]