Honda Car Forum

I agree that a properly maintained master cylinder should work it's
full usable bore. However, I also agree that brake fluid is
hydroscopic and it contributes to the bore corrosion problems
mentioned.

So in a poorly maintained master cylinder even with a protective
coated bore, I personally wouldn't count too much on the full use of
the backup hydraulic circuit, at least for too long

As far as rubber swell -- I was reading Tegger's site on his MC
repalcement. So I'll leave that to him.


From Valvoline's site, on master cylinder water damage:
http://www.valvoline.com/carcare/art...=ccr20020401mc

"Water Damage
Master cylinder leaks are normally caused by corrosion within the
horizontal cylinder. Brake fluid is hydrostatic [sic], which means it
attracts water. The water in the brake fluid can cause rust pitting
inside the fluid cylinder resulting in fluid leaking past the rubber
plunger. Once this happens the only cure is a rebuild or master
replacement."




On Mar 2, 6:40*pm, jim beam <retard-t...@bad.example.net> wrote:
> how? *if the new fluid shrinks the seals, then not pumping them isn't
> going to save them.
>
> besides, the master cylinder /should/ work, new fluid, all the way,
> regardless. *imagine you cut a brake line, debris or whatever, and now
> you only have one circuit working. *suddenly, you're going to want to
> use the "unused" portion of the master cylinder real damned quick, and
> having that suddenly fail because you've never checked that it worked
> all the way last time you bled the brakes could suddenly be just a
> teensy weensy little bit inconvenient.
>
> bleeding kits are for speed, convenience and one-man operation, not seal
> preservation.

johngdole@hotmail.com wrote:
> I agree that a properly maintained master cylinder should work it's
> full usable bore. However, I also agree that brake fluid is
> hydroscopic and it contributes to the bore corrosion problems
> mentioned.
>
> So in a poorly maintained master cylinder even with a protective
> coated bore, I personally wouldn't count too much on the full use of
> the backup hydraulic circuit, at least for too long

nor would i - but the point is, you want it to work that /one/ time you
need it to!


>
> As far as rubber swell -- I was reading Tegger's site on his MC
> repalcement. So I'll leave that to him.
>
>
> From Valvoline's site, on master cylinder water damage:
> http://www.valvoline.com/carcare/art...=ccr20020401mc
>
> "Water Damage
> Master cylinder leaks are normally caused by corrosion within the
> horizontal cylinder. Brake fluid is hydrostatic [sic],

yeah, good one. that should read: "hygroscopic".


> which means it
> attracts water. The water in the brake fluid can cause rust pitting
> inside the fluid cylinder resulting in fluid leaking past the rubber
> plunger. Once this happens the only cure is a rebuild or master
> replacement."
>

another reason to use aluminum cylinders - like honda do!



>
>
>
> On Mar 2, 6:40�pm, jim beam <retard-t...@bad.example.net> wrote:
>> how? �if the new fluid shrinks the seals, then not pumping them isn't
>> going to save them.
>>
>> besides, the master cylinder /should/ work, new fluid, all the way,
>> regardless. �imagine you cut a brake line, debris or whatever, and now
>> you only have one circuit working. �suddenly, you're going to want to
>> use the "unused" portion of the master cylinder real damned quick, and
>> having that suddenly fail because you've never checked that it worked
>> all the way last time you bled the brakes could suddenly be just a
>> teensy weensy little bit inconvenient.
>>
>> bleeding kits are for speed, convenience and one-man operation, not seal
>> preservation.
>

to labor the point, i've done many a brake job over the years, and yes,
i've seen many a master cylinder go south just a few weeks after fluid
change or bleeding. but here's the thing - that same thing can happen
when you bleed the system with a pressure kit and don't even /touch/ the
master cylinder. it's all a function of age and condition. if the
fluid in the master cylinder looks cloudy and black, the seals are
degrading and will soon leak. if the fluid turns brown, it's simply
moisture and can be replaced with no further worries. if i see black, i
replace or re-seal - no point messing about.

johngdole@hotmail.com wrote in news:272d7e9b-519a-4bc9-b2a8-bcdf9107bdb9
@w1g2000prk.googlegroups.com:

> Sounds like both Jim Beam and Tegger are right -- under different
> circumstances.



/I'm/ not right, HONDA is right.


>
> Well eqiupped shops use pressure/vacuum bleeders. So the brake pedal
> isn't pumped during the process. However, the brake pedal should be
> depressed a little (past the vent port) so the area behind the seal
> can be flushed.



The area behind the rear seal is in the open air, so you can't flush that.
The area behind the front seal has the fluid for the rear chamber. You
flush this area automatically when that circuit is bled.





--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

jim beam <retard-trap@bad.example.net> wrote in
news:Ao-dnUZK6fhHDDHUnZ2dnUVZ_g2WnZ2d@speakeasy.net:

> Tegger wrote:
>
>> jim beam <retard-trap@bad.example.net> wrote in
>> news:sfWdnf3RIcT9eTbUnZ2dnUVZ_gmWnZ2d@speakeasy.ne t:
>>
>>>>
>>>>
>>> there's not much danger to seals from the process - it's almost
>>> always chemical. fresh fluid causes slight sizing change, and on
>>> worn seals, that can cause leakage. for this mileage, if you're not
>>> doing the work yourself, it's probably cost effective to simply
>>> replace.
>>
>>
>>
>> Honda says differently.
>> http://www.tegger.com/hondafaq/misc/A011000.pdf
>>
>>
>
> written locally, not in japan.



And our cars are driven locally, not in Japan, so the page is most
definitely relevant.

And I'm unable to find any HSN mentions of seal shrinkage due to new
fluid, so I'm guessing Honda has found friction damage to be far more
prevalent than seal shrinkage.




> bottom line - the cylinder needs to be
> effective through the full stroke, any time, any reason. period. if
> it's not, it needs to be replaced.



Yes, but if the brakes have failed to the point that you need to rely on
the "last resort" fallback of the one working circuit, the entire system
needs later to be looked at and repaired by a professional (provided the
car didn't get wrecked), so MC condition is not the most important issue
right then. Brakes in that bad shape will likely need a replacement MC
anyway.




> besides, as you yourself show with
> the internal condition of your own master cylinder rebuild on your web
> site, the corrosion inhibitors in modern fluids pretty much prove this
> to be ancient history.



My brake fluid is changed every single year, as I also say in that page.



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

johngdole@hotmail.com wrote in
news:f299aa08-6dae-4bf7-876f-124ddd05c083@k29g2000prf.googlegroups.com:

> Sure, the cost of a flush ~$100 is probably better applied towards a
> new master cylinder. IIRC the Honda OEM online dealer sells for about
> $100.



Depends on the car. For my Integra, an OEM MC is about $350. An aftermarket
reman is about $75.

And if you replace the MC, the system needs to be bled anyway, so I don't
see how you'd save the labor charge for that.



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Tegger wrote:
> jim beam <retard-trap@bad.example.net> wrote in
> news:Ao-dnUZK6fhHDDHUnZ2dnUVZ_g2WnZ2d@speakeasy.net:
>
>> Tegger wrote:
>>
>>> jim beam <retard-trap@bad.example.net> wrote in
>>> news:sfWdnf3RIcT9eTbUnZ2dnUVZ_gmWnZ2d@speakeasy.ne t:
>>>
>>>>>
>>>> there's not much danger to seals from the process - it's almost
>>>> always chemical. fresh fluid causes slight sizing change, and on
>>>> worn seals, that can cause leakage. for this mileage, if you're not
>>>> doing the work yourself, it's probably cost effective to simply
>>>> replace.
>>>
>>>
>>> Honda says differently.
>>> http://www.tegger.com/hondafaq/misc/A011000.pdf
>>>
>>>
>> written locally, not in japan.
>
>
>
> And our cars are driven locally, not in Japan, so the page is most
> definitely relevant.

as shown by the corrosion here?
http://www.tegger.com/hondafaq/maste...inder-bore.jpg


>
> And I'm unable to find any HSN mentions of seal shrinkage due to new
> fluid, so I'm guessing Honda has found friction damage to be far more
> prevalent than seal shrinkage.

why guess? seal swelling and shrinkage is such a known issue, it's part
of the spec to which brake fluids are manufactured.


>
>
>
>
>> bottom line - the cylinder needs to be
>> effective through the full stroke, any time, any reason. period. if
>> it's not, it needs to be replaced.
>
>
>
> Yes, but if the brakes have failed to the point that you need to rely on
> the "last resort" fallback of the one working circuit, the entire system
> needs later to be looked at and repaired by a professional (provided the
> car didn't get wrecked), so MC condition is not the most important issue
> right then.

with respect dude, if it's the only thing you have left after one
circuit has failed, it most definitely /is/ important.


> Brakes in that bad shape will likely need a replacement MC
> anyway.

i've been saying that all along.


>
>
>
>
>> besides, as you yourself show with
>> the internal condition of your own master cylinder rebuild on your web
>> site, the corrosion inhibitors in modern fluids pretty much prove this
>> to be ancient history.
>
>
>
> My brake fluid is changed every single year, as I also say in that page.

as you should.

Tegger wrote:
> johngdole@hotmail.com wrote in
> news:f299aa08-6dae-4bf7-876f-124ddd05c083@k29g2000prf.googlegroups.com:
>
>> Sure, the cost of a flush ~$100 is probably better applied towards a
>> new master cylinder. IIRC the Honda OEM online dealer sells for about
>> $100.
>
>
>
> Depends on the car. For my Integra, an OEM MC is about $350. An aftermarket
> reman is about $75.
>
> And if you replace the MC, the system needs to be bled anyway, so I don't
> see how you'd save the labor charge for that.
>
>
>

you save by not having the job done twice. just changing the fluid,
then coming back a month later because the cylinder's gone is a waste of
money.

jim beam <retard-trap@bad.example.net> wrote in
news:fbCdneDqJf5EcDDUnZ2dnUVZ_tmWnZ2d@speakeasy.ne t:

> Tegger wrote:

> as shown by the corrosion here?
> http://www.tegger.com/hondafaq/maste...ssembly/inside
> -master-cylinder-bore.jpg


The fluid in that cylinder was changed EVERY YEAR. Corrosion happens when
you NEVER change it. That photo is a testament to the effects of frequent
fluid changes, not to the resistance of aluminum to corrosion.


>
>
>>
>> And I'm unable to find any HSN mentions of seal shrinkage due to new
>> fluid, so I'm guessing Honda has found friction damage to be far more
>> prevalent than seal shrinkage.
>
> why guess? seal swelling and shrinkage is such a known issue, it's
> part of the spec to which brake fluids are manufactured.




But my point is that Honda went out of their way to explain the phenomenon
of friction damage, so that's a known issue as well.



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Tegger wrote:
> jim beam <retard-trap@bad.example.net> wrote in
> news:fbCdneDqJf5EcDDUnZ2dnUVZ_tmWnZ2d@speakeasy.ne t:
>
>> Tegger wrote:
>
>> as shown by the corrosion here?
>> http://www.tegger.com/hondafaq/maste...ssembly/inside
>> -master-cylinder-bore.jpg
>
>
> The fluid in that cylinder was changed EVERY YEAR. Corrosion happens when
> you NEVER change it. That photo is a testament to the effects of frequent
> fluid changes, not to the resistance of aluminum to corrosion.

dude, with respect, the aluminum cylinder is most definitely part of the
reason. oh, and efforts of the chemists for the fluid.


>
>
>>
>>> And I'm unable to find any HSN mentions of seal shrinkage due to new
>>> fluid, so I'm guessing Honda has found friction damage to be far more
>>> prevalent than seal shrinkage.
>> why guess? seal swelling and shrinkage is such a known issue, it's
>> part of the spec to which brake fluids are manufactured.
>
>
>
>
> But my point is that Honda went out of their way to explain the phenomenon
> of friction damage, so that's a known issue as well.
>
>
>

ok, serious question: for /your/ master cylinder, knowing what you do
about its internal condition, what makes you argue for an old wives tale?

On Mar 1, 5:03*pm, "Pete" <archer1...@verizon.net> wrote:
> I have a 99 Civic with 230k miles and I've never changed the brake fluid.
> But I just read an article about moisture content decreasing the boiling
> point of the fluid over time. *Now I'm concerned about the master cylinder
> because I've never changed the fluid. *Any thoughts?
>
> Pete

you should also be concerned about the condition of the brakes at all
4 wheels if routine maintenance was neglected for 10 years. however,
it is unlikely that you've gone 230K miles on the original brakes pads/
shoes. and it is also unlikely that when someone installed a new set
of pads/shoes they did not also flush the brake fluid. check your
receipts for brake work. odds are your brake fluid has been flushed
several times.

now I return you to the tegger/jim beam show already in progress...