Testing/Inspecting Brake Master Cylinder

I have a question regarding the master brake cylinder, on the 1980 Honda
Civic I'm attempting to restore. When I acquired this vehicle, the brakes
were totally non-functional, and depressing the brake pedal produced a
strange groaning noise from the master cylinder area. I later discovered
that one wheel cylinder was missing and the fluid had been allowed to drain
from that line. The other three lines were still connected and still
contained fluid. However, the fluid reservoir was empty - but I don't know
for how long. If it was empty to start with, it probably has been for the
last several years the car has been sitting. Otherwise it's only been a
couple of months.
I'm told that the seals on the piston will dry up and crack in the absense
of brake fluid, necessitating replacement. But should I automatically assume
my cylinder needs replacing, or is there any way to inspect it or perhaps
test it (while driving around in the yard, for example). I'd rather not
replace it unless I had to. I am however replacing all of the brake lines,
and the rear wheel cylinders, just to avoid problems down the road.
Thanks for any advice.

Chris F. wrote:
> I have a question regarding the master brake cylinder, on the 1980 Honda
> Civic I'm attempting to restore. When I acquired this vehicle, the brakes
> were totally non-functional, and depressing the brake pedal produced a
> strange groaning noise from the master cylinder area. I later discovered
> that one wheel cylinder was missing and the fluid had been allowed to drain
> from that line. The other three lines were still connected and still
> contained fluid. However, the fluid reservoir was empty - but I don't know
> for how long. If it was empty to start with, it probably has been for the
> last several years the car has been sitting. Otherwise it's only been a
> couple of months.
> I'm told that the seals on the piston will dry up and crack in the absense
> of brake fluid, necessitating replacement. But should I automatically assume
> my cylinder needs replacing, or is there any way to inspect it or perhaps
> test it (while driving around in the yard, for example). I'd rather not
> replace it unless I had to. I am however replacing all of the brake lines,
> and the rear wheel cylinders, just to avoid problems down the road.
> Thanks for any advice.
>
>

I've had 2 master cylinders fail on me. My bet is that you'll have no
qualms about replacing it when that one fails on you. How expensive is a
Honda MC? I remember the replacements for my cars to be around $60.

On Fri, 30 Oct 2009 16:06:16 -0700, Chris F. wrote:
> I'm told that the seals on the piston will dry up and crack in the absense
> of brake fluid, necessitating replacement.

What happened on my truck was that one of the wheel cylinders went bad and
all the fluid disappeared - when it did so, years of accumulated crap in
the resevoir was drawn into the master cylinder. Some of the crap stuck
itself between the piston seals and bore of the master cylinder, which
meant it started leaking.

I stripped the whole lot down, cleaned, inspected the bore for corrosion,
checked the seals etc. and reassembled, and it's been fine since. I
disconnected the brake lines and pumped a whole bunch of fluid through
them to flush them, then stripped + cleaned + checked all the wheel
cylinders (most of them were full of crap, too).

This was with a servo with no vacuum assist (too old) whereas I'm sure
yours is - although I don't suspect they're that much more complicated to
pull apart.

cheers

Jules

"Chris F." > wrote in
:

> I have a question regarding the master brake cylinder, on the 1980
> Honda
> Civic I'm attempting to restore. When I acquired this vehicle, the
> brakes were totally non-functional, and depressing the brake pedal
> produced a strange groaning noise from the master cylinder area. I
> later discovered that one wheel cylinder was missing and the fluid had
> been allowed to drain from that line. The other three lines were still
> connected and still contained fluid. However, the fluid reservoir was
> empty - but I don't know for how long. If it was empty to start with,
> it probably has been for the last several years the car has been
> sitting. Otherwise it's only been a couple of months.
> I'm told that the seals on the piston will dry up and crack in the
> absense
> of brake fluid, necessitating replacement. But should I automatically
> assume my cylinder needs replacing, or is there any way to inspect it
> or perhaps test it (while driving around in the yard, for example).
> I'd rather not replace it unless I had to. I am however replacing all
> of the brake lines, and the rear wheel cylinders, just to avoid
> problems down the road.
> Thanks for any advice.
>
>


Chris, these are /brakes/ you're talking about. Brakes are what keep you
from smashing into things that will damage your finely-restored ride and
may perhaps even make you not-alive anymore.

A reman aftermarket MC from your local NAPA is about $80-100. Do **NOT**
cheap out on this part. Deliver a few more pizzas or newspapers, or sponge
off the relatives to raise the money. Just don't try to make do with the
existing MC.


--
Tegger

On Sat, 31 Oct 2009 01:20:35 +0000, Tegger wrote:

> Just don't try to make do with the existing MC.

Yes, don't think I mentioned that in my post, but hopefully it's obvious :-)

I figured as much. I can get an aftermarket MC on Ebay for about $75
shipped, so I guess that's what I'll do. You're right, it's not worth taking
chances with.

"Jules" > wrote in message
news
> On Fri, 30 Oct 2009 16:06:16 -0700, Chris F. wrote:
>> I'm told that the seals on the piston will dry up and crack in the
>> absense
>> of brake fluid, necessitating replacement.
>
> What happened on my truck was that one of the wheel cylinders went bad and
> all the fluid disappeared - when it did so, years of accumulated crap in
> the resevoir was drawn into the master cylinder. Some of the crap stuck
> itself between the piston seals and bore of the master cylinder, which
> meant it started leaking.
>
> I stripped the whole lot down, cleaned, inspected the bore for corrosion,
> checked the seals etc. and reassembled, and it's been fine since. I
> disconnected the brake lines and pumped a whole bunch of fluid through
> them to flush them, then stripped + cleaned + checked all the wheel
> cylinders (most of them were full of crap, too).
>
> This was with a servo with no vacuum assist (too old) whereas I'm sure
> yours is - although I don't suspect they're that much more complicated to
> pull apart.
>
> cheers
>
> Jules
>

"Chris F." > wrote in
:

> I figured as much. I can get an aftermarket MC on Ebay for about $75
> shipped, so I guess that's what I'll do. You're right, it's not worth
> taking chances with.



I'd recommend you buy from NAPA or other local supplier. That way your
warranty will actually be worth something if things should go wrong, which
is common with aftermarket parts.



--
Tegger

Do you have any experience with Centric brake products? I have to order a
brake spring/hardware kit from one of their distributors, and I could order
an MC from the same place while I'm at it.
"Tegger" > wrote in message
...
> "Chris F." > wrote in
> :
>
>> I figured as much. I can get an aftermarket MC on Ebay for about $75
>> shipped, so I guess that's what I'll do. You're right, it's not worth
>> taking chances with.
>
>
>
> I'd recommend you buy from NAPA or other local supplier. That way your
> warranty will actually be worth something if things should go wrong, which
> is common with aftermarket parts.
>
>
>
> --
> Tegger
>
>

"Chris F." > wrote in
:
>
> "Tegger" > wrote in message
> ...
>>
>> "Chris F." > wrote in
>> :
>>
>>> I figured as much. I can get an aftermarket MC on Ebay for about $75
>>> shipped, so I guess that's what I'll do. You're right, it's not
>>> worth taking chances with.
>>
>>
>>
>> I'd recommend you buy from NAPA or other local supplier. That way
>> your warranty will actually be worth something if things should go
>> wrong, which is common with aftermarket parts.
>>
>>
>
>
> Do you have any experience with Centric brake products? I have to
> order a brake spring/hardware kit from one of their distributors, and
> I could order an MC from the same place while I'm at it.



No experience whatsoever with "Centric". But if they're anything like any
other aftermarket suppliers, their quality for Honda parts will be
hit-and-miss.

You can go ahead and order from them, but keep your receipt until the
warranty is up. Chances are good you'll be making use of that warranty.

I happen to be running an aftermarket-reman MC bought from a local NAPA in
2005. It's still working just fine. It was $70 versus $350 for new OEM
Honda (Nissin). I consider myself lucky.


--
Tegger

But should I automatically assume
> my cylinder needs replacing, or is there any way to inspect it or perhaps
> test it

Absolutely, I do it all the time.
Take the master cylinder apart and pry the rubber pistons off.
Using a sharp razor blade, carefully cut them all in half and check
for dryness inside.
Its the only safe sure way to know for certain.
I do the same with carb floats...