How much brake fluid would ge good?

'sup all,

I've got a 1993 Honda Accord and I'm going to change my master
cylinder, as well as replace the brake fluid that's in there. I was
thinking about letting gravity drain the fluid from the reservoir and
replace the fluid as it drains. Is that a good idea? I wonder if I
don't get it all out, how would the two different (assuming just
different in age) behave together? Old vs. New. I guess I should get
a little bit more fluid to drain it good.

Then I was going to replace the Master Cylinder. I need to take the
brake hoses off, but do I drain the reservoir first? Maybe until
almost empty. my main quandry is How does air not get into the brake
lines when I unscrew them from the old master cylinder?

How much brake fluid does anyone recommend I should get to drain
the system fully and put the new MC on? I was thinking one of those
big bottles, like 1Ltr. or something would do, though I don't know how
much fluid the system even contains.

Could anyone help me with this? How much brake fluid is in the
system? I don't want to run out, but I don't know what I'd do with
alot of extra fluid either. maybe I'll just flush until I have enough
to fill the MC plus a little bit more for later <grin>

 

Old fluid conains water, its going to boil at a lower temp.

Doesn't matter, you bleed the brakes afterwards. only way, since
there's gong to be air in the cylinder to push out as well

Always buy more - brake fluid isn't exactly 'honda coolant' price. Or,
alternatively, buy lots of smaller bottles, since you can't really
store open bottles (moisture gets in and it goes bad)

yep, pretty much, I think a 1l bottle should be plenty.

 

I googled on this a few weeks ago, just before flushing my
91 Civic's brake system.

Seems one to two 32-oz. bottles is the consensus to flush
the system. I used a little less than 32-oz after noting the
fluid coming out was pretty clean.

I use a Mity-Vac vacuum pump to bleed the brakes. It takes a
suction at the bleeder screws. A good one costs around $40.
Available via Harbor Freight, among other places.

I'd be in the free online manual at www.autozone.com for
your car for the master cylinder removal etc. directions.
Or, better, use the factory service manual for your 93
Accord at http://www.honda.co.uk/car/owner/workshop.html

 

buy 32oz and use it all. disgard any surplus. best way to bleed the
front calipers is to open the bleed nipple, then push the piston all the
way back in. all the old fluid gets forced out. it's disgusting too.
/then/ when you change the m/c, all the clean stuff coming through has a
really good start. the rears are less important.

wash any brake fluid spillage off bodywork immediately with water. DO
NOT WIPE UNDER ANY CIRCUMSTANCES!!! trust me on that one.

 

In addition to the other warnings (especially about cleaning it off paint
without delay) I would add that brake fluid is an organic oil - if you leave
rags contaminated with brake fluid in a pile they may spontaneously burst
into flame.

Disposal is best done by dumping the old fluid back into the bottle - as
mentioned, it doesn't store well once opened - closing it tightly and
putting it into the trash. In theory it can be poured onto the ground
because it is biodegradable, but that doesn't seem kosher when a better
method is available. Or, I suppose you could burn it in an oil lamp....

Mike

 

I couldn't disagree more. It's pretty easy, and a lot more friendly on the
environment, to store the old brake fluid and dispose of it at a repair
shop usually for a small fee or dispose of it for free at a community
household hazardous waste collection day (my community has those about 2 or
3 times a year and they're great for getting rid of small quantities of old
chemicals, oil, etc).

Eric

 

You can use a large syringe to remove all of the brake fluid from the master
cylinder reservoir and then bleed the brakes as per the service manual's
instructions.

Eric

 

I'll go along with that - leaving the details to professionals at no cost to
us. They may even have a recycling program. Thanks, Eric.

Mike

 

How much brake fluid would be good...hmmm...interesting question. As a
start, enough to fill all the lines and the reservoir.

Flush ALL of the old fluid out and use only new fluid. And be sure to
bleed the brakes following the manufacturers recommended procedure for
that car.

I'm more than a bit concerned by your questions because they tell me
you don't have a lot of experience working on brakes. Brake work can
be done at home, but someone at the work site has to be knowlegable in
how a brake system works. My strong suggestion is that you either ask
a friend who has that knowlege to sit with you or that you have a
mechanic do the work. Brakes are not something you want to have fixed
just part of the way.

 

Okay,

Thanks for all the responses!!

From suggestions, I gather that I should empty the brake system
first, and then replace the master cylinder. I can pump the new fluid
into the system after I install the new MC, correct?

That sounds like a good Idea actually. I was going to flush AFTER
installing the new MC, but I guess I could get some old/new fluids
mixed together that way.

Has anyone tackled replacing a Master Cylinder?

I am concerned about setting the pushrod freeplay. Any
suggestions? The honda manual has a special tool that is used, and
Tegger's method of MC changes (at his website
http://www.tegger.com/hondafaq/mastercylinderreplace/index.html) uses
an alternate and interesting approach as well. This would be my main
concern, as I wouldn't want my brakes to slowly lock on me while
driving, nor would I want them to not slow me down...<grin>

Thanks all...

 

One more time...have someone there who has done more than one brake job

 

i did it in my 88 civic december 04. had to walk to the advance to get
the parts, walk back, and then fit it. Had to work kinda quick too,
since my wife had to use it for a job interview the next morning (it
was our only car at the time). alas, the house had no garage, or
shelter, and was below freezing by the time i finished, at 2am. Did it
on a similar age caravan about ayear ago, went much smoother, thanks
to the practice. both times i had haynes manuals to help me through
it.

 

Your thinking was correct. Flush the system AFTER replacing the master
cylinder. Remove the fluid from the reservoir of the old master cylinder
first, replace the master cylinder after you've bench bled it (check your
service manual for bench bleeding instructions), and then flush the whole
brake system until you get clean fluid from each caliper/wheel cylinder. I
strongly recommend AGAINST draining the whole system and then trying to
bleed it. There will be so much air in the system you'll be bleeding it for
a long, long time.

Eric

 

OK, here's one of my old posts which describes bench bleeding a master
cylinder, http://tinyurl.com/o5t6q.

Eric

 

Yep -- one still sees some advice about various means of informal
disposal; but the most up-to-date thinking is that used brake fluid
(or is it all brake fluid?) should be disposed of as hazmat. I think
the issue is some kind of heavy metal that's in there. And since
it's a glycol rather than a petroleum oil, you aren't supposed to put
it in with your motor oil/tranny fluid either.

If your town has a household hazmat center, that's a good place to take
it. Or see if the auto parts store where you bought the brake fluid
will accept it.

As for how much to buy -- get the big bottle and a couple of little
ones, or two big bottles (it isn't that expensive). Who wants to get
cleaned up and schlep down to the auto parts store halfway through the
job because they didn't have enough brake fluid? (Especially if you're
working on your only car!) And an unopened, sealed bottle will last.
Any opened bottle, on the other hand, should go into the waste bottle
with the old stuff (preferably after being pulled through the system
with your Mityvac or whatever other bleeding scheme you use).

Don't forget to bench-bleed the new master cylinder, too. In this and
other aspects, follow the instructions in the shop manual for the car.


Finally: after doing any brake work, do not set the car in motion
until you get a correct pedal feel, and proceed carefully for a few
blocks (stopping repeatedly) until you gain justified confidence in the
job.

Best of luck,
--Joe

 

Thanks guys and gals,

this is great data. Has anyone come across problems/solutions to
adjusting the freeplay on the pushrod? This was mentioned in the
manual and from other sources. This is my main concern.

After removing the brake lines from the old MASTER CYLINDER is there
any worries about getting air into the brake lines w/ the cylinder off?
Do these brake lines have a valve or anything that opens when it gets
screwed on to the master cylinder, or are they exposed to potential air
contamination?

I appreciate it all...

 

Here's what I did on my car ('91 Integra):
http://www.tegger.com/hondafaq/mastercylinderreplace/index.html
For pushrod adjustment, see parts 6 and 7.

Pushrod adjustment is one of the things I ended up having to do before my
pedal felt correct.

I didn't have any problems with air getting into the lines. Read the link
above and you'll see why.

 

You got air int he cylinder, the new one. you're going to have to push
it out via the lines anyway, who cares if theres a little more air int
he lines? Its not a big deal, since you're gong to be pushing the rest
of the crap out. look at the system, and apply a small amont of common
sense.

 

Tegger,
I've read your pages many times. I am just a little in the dark
when it comes to knowledge about those fluid pipes that screw into the
master cylinder. I've been browsing that topic at your site for a
while now, though the only thing I found of this problem is : (I'm
using a quote out of one of the pages at that link you provided)
"The open hydraulics on the MC will start to drip as soon as you remove
the fittings. The fluid in the lines didn't drip out, so no danger of
air in the lines that way"

Can I ask a bit about this? I'm assuming the lines are stought
enough that they don't sway much when disconnected from the MC and we
can face them upwards so not to spill the fluid. I understand there
will be some fliud dripping out, but I just want to be as certain as I
can that I fully understand what you're saying about the procedure.
Thinking about it just now I don't know that it would be horrible if a
bit of air got in. I have to flush it anyways and the air should get
bled out from that.

Thanks all for the advice...

 

they don't wave about, but don't bend them. there's enough flex there
that you can move them temorarily out of the way, but again, do not
permanently bend the metal pipes.

the fluid doesn't usually run out of the pipes unless you have a bleed
nipple open downstream. [the pipe internal diameter is chosen
specifically so that doesen't happen.] you can therefore, at a pinch,
and this is not recommended, bleed the m/c direct at the pipe connectors
and not even bleed the rest of the system. again, that's not
recommended, but it can be done because the pipes don't usually empty on
their own.

yes, fully bleed afterwards. use the full "have an assistant push the
pedal to the floor" technique, especially on a new m/c as the preserving
fluid that's in there can sometimes cause airlocks.