> I have a 91 Honda Accord, great car. However recently I have been
> losing brake fluid. About one a week I have to fill the reservoir.
[quoted text clipped - 3 lines]
> Very wierd. Anyone seen anything like this or know of any other
> explanation? Any help is appreciated.
My car had a similar problem. Turned out to be a loose brake hose on the
right rear drum. The fluid was dripping ever so slightly from the hose
and running down the inside of the rim. Very difficult to notice.

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jim beam <nospam@example.net> wrote in news:28udnfMQZoZO8LLeRVn-
gQ@speakeasy.net:
>> I have a 91 Honda Accord, great car. However recently I have been
>> losing brake fluid. About one a week I have to fill the reservoir.
[quoted text clipped - 8 lines]
> leaks should be obvious. check /all/ brake lines & hoses as well as
> calipers, drums, etc.
HIGHLY unlikely it's leaking into the booster. Two O-rings seal that end up
awfully well. And it cannot leak into the car at all unless it first fills
up the booster then perforates the diaphragm, then fills up the other side
as well.
I think the OP has a holed line or it's leaking out of a caliper or into a
drum (if so equipped). Drums must be /removed/ to check.
Have helper step HARD and steadily on pedal, and watch underneath for
drips. If leak is mild, wind will sweep fluid away at speed. Best to have
car on hoist & have strong light. Hold pedal for five minutes or more.
Does car have ABS?
Additional slightly possible source of leaks is base of reservoir. If clamp
is loose or body is corroded, fluid can seep past.
Does car have other leaks that could obscure leaking brake fluid?

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The Unofficial Honda/Acura FAQ
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jim beam - 21 Sep 2005 03:42 GMT
> jim beam <nospam@example.net> wrote in news:28udnfMQZoZO8LLeRVn-
> gQ@speakeasy.net:
[quoted text clipped - 16 lines]
> up the booster then perforates the diaphragm, then fills up the other side
> as well.
i've seen it. not on a honda, but i have seen it.
> I think the OP has a holed line or it's leaking out of a caliper or into a
> drum (if so equipped). Drums must be /removed/ to check.
[quoted text clipped - 9 lines]
>
> Does car have other leaks that could obscure leaking brake fluid?
TeGGeR® - 21 Sep 2005 12:27 GMT
>> HIGHLY unlikely it's leaking into the booster. Two O-rings seal that
>> end up awfully well. And it cannot leak into the car at all unless it
>> first fills up the booster then perforates the diaphragm, then fills
>> up the other side as well.
>
> i've seen it. not on a honda, but i have seen it.
Some MC designs (especially older unboosted designs) did not seal the rear
of the plunger well. Those can leak into the car.
The Honda MCs I've seen have all had a rear plug with two O-rings. Leakage
from that is VERY rare. And even then it would have to fill up both sides
of the booster before leaking into the car. The booster could hold an awful
lot of fluid.
He's got a leak somewhere else, I'm convinced. Just nobody's finding it.

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roadcyc@socal.rr.com - 22 Sep 2005 21:04 GMT
My money is on: fluid leaking into the vacuum booster.
TeGGeR® - 23 Sep 2005 01:24 GMT
> My money is on: fluid leaking into the vacuum booster.
Basically, that's completely impossible. The rear chamber has no pressure
in it.
http://www.tegger.com/hondafaq/mastercylinderreplace/howworks.html

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jim beam - 23 Sep 2005 04:10 GMT
>>My money is on: fluid leaking into the vacuum booster.
>
> Basically, that's completely impossible.
not so - it's extremely common for the bore seal to go. look around a
junk yard and you'll see boosters with leakage evidence [missing paint]
all the time. the question is whether it will leak /into/ the booster,
and while the honda booster has a drain where the cylinder is mounted to
mitigate this, it can still happen. it depends on how greased up the
original seal was and whether the drain is plugged.
> The rear chamber has no pressure
> in it.
doesn't need it. in fact, seals don't leak much under pressure because
they get pressed against the cylinder wall. it's seepage from when the
seals are relaxed that is the biggest problem.
> http://www.tegger.com/hondafaq/mastercylinderreplace/howworks.html
utahgolfer - 24 Sep 2005 02:51 GMT
How can you check the booster?
utahgolfer - 24 Sep 2005 03:03 GMT
I will remove the drums and look again at everything. Yes it has ABS.
No other leaks.