Brake Line Replacement

Scott Dorsey wrote:

> . I did
> have to replace a number of brake lines due to external rust, but
> when I cut them open they were nice and clean inside. So here was
> thirty-year-old fluid (because I _know_ these bozos never changed
> anything on any schedule), doing its job perfectly well.

Do you believe this car never had any brake work that involve bleeding the
brakes in 30 years?



>
> That's basically the way I think about it. If the system is perfectly
> sealed, there's no real need to change it, but I worry about how well
> sealed it really is.

The original poster's mechanic is correct to suggest changing the brake
lines. Regular use of the vehicle seems to help protect against corrosion to
brake lines to some extent. It is not uncommon to have the brake lines pop
after an car has been left sitting for a year. If you replace just the on
that goes first then another will let loose.



>
>
> >BTW, my '90 Corsica probably has the original fluid in it and brakes
> >fine. I bought it 11 years ago. Last year a rear line rusted through
> >from the outside. So it got a dose of new fluid for the bleed.
>
> I'm currently having an inexplicable clutch issue that is clearly
> related to the hydraulics. Changed out _everything_ over the course
> of a couple years, including both cylinders and all the piping, and
> I thought it had gone away until the warm weather started up and now
> it's back again. Either air is mysteriously getting into the system
> somewhere, or there's a particle somewhere in the system that is moving
> around. I've flushed everything several times now.... may be related
> to fluid breakdown, then again maybe it's not...

Clutches are a little different than brakes. The way brakes are designed it
isn't likely to ever get negative pressure in the system.

-jim

Ulf wrote:
>
> Chris F. wrote:
> > Me again with this '88 Civic project. This car has been parked for about 8
> > months now, and a mechanic recently told me that this is very bad for the
> > brake lines. He said I should replace all the steel lines to prevent
> > problems down the road. This involves a lot of extra work though; is it
> > really necessary?
> >
> >
> Sounds like bull**** to me.
>
> Brake lines only corrode from the outside, IME. Change the brake fluid
> and inspect the hoses. Unless you live where salt is used extensively in
> the winter, the brake lines will most probably be alright.


Nope your wrong. Brake lines do definitely corrode from the inside when
a vehicle is left to sit for a long period of time. The same is true of
wheel cylinders. The pitting and corrosion is always at the bottom of a
wheel cylinder and/or always at the lowest point in stretch of brake
line.

-jim

It's worth noting that the brake lines on this car, run along the inside of
the passenger compartment rather than along the underside. However, they
have been disconnected and sitting all winter.... I will probably replace
the lines anyway since I don't want to risk failure down the road.

"ray" > wrote in message
...
> Chris F. wrote:
>> Me again with this '88 Civic project. This car has been parked for
>> about 8 months now, and a mechanic recently told me that this is very bad
>> for the brake lines. He said I should replace all the steel lines to
>> prevent problems down the road. This involves a lot of extra work though;
>> is it really necessary?
>
> Is this a project car or a beater? On an 88 that's seen 20 winters with
> lots of snow and salt and stuff, the brake lines are probably pretty much
> compressed rust. My winter beater's a 90 Beretta and the lines are pretty
> much done - I had to splice one in recently after it sprung a leak and the
> rest of the lines all pretty much look like crap.
>
> Brake lines are cheap. Replacing them on a project car = good idea and
> way easier to run the lines when there's less stuff in the way.
> Preemptively replacing all the brake lines on a beater = waste of money.
> Either replace them when they burst and risk an accident, or find the
> rusty parts and splice in new lines (you can flare the line right on the
> car) or don't drive a beater.
>
> (I had to drive home using nothing but the e-brake when the line blew. You
> can do it, but it's nerve wracking as hell and you have to leave a
> ****load of room. the car still had front brakes but was leaking bad, I
> stopped for more fluid on the way home. I probably should have taken a
> cab and gone back with my truck and trailer, but I'm too stubborn.)
>
> Ray

"Scott Dorsey" > wrote in message
...

>
> It could be, I don't know the inhibitor chemistry in these things.

I may be wrong, Scott, but I dont believe there is any corrosion inhibitor
in the
brake fluid. These polyols are not very corrosive against steel or copper,
unless
wet or contaminated.


( Typically when they come out of the reactor, they will contain
less than 0.02% water. But they will absorb water for quite a while. That
is why
similar compounds are used to remove water from natural gas (in a cloud
point unit,
or gas dehydrator) before it enters the pipelines. )

The common ones are, however, miscible with water in any concentration, but
that doesnt mean that they will continue to absorb water at the same rate as
they approach saturation.

Many of us have seen master cylinders and wheel cylinders destroyed by
corrosion. Some of that has had to do with poor quality hard parts in the
past.

Ashton Crusher > wrote:
>
>Interesting article. I ran across an article quoting Ford engineers
>about the whole 'water in brake fluid' thing. In short, they have
>studied it and found that the amount of water that's absorbed gets
>absorbed early on and then stabilizes.

Yes, this is clearly the case. Hopefully if the system stays sealed, the
only water that gets absorbed is a tiny amount when the system is first
filled.

But, if the system isn't completely sealed, it will absorb some amount of
water and then saturate pretty quickly. Then it will stay in this state
for years.

>Unless you keep opening the
>system up they concluded that there was no reason to flush the system
>other then flushing it when you did normal brake service for pads,
>etc. It can't hurt to flush but some people are way too anal about
>it.

Yes, the severe service schedule on my '85 suggests doing it every five
years. That sounds reasonable enough. You might get away with never doing
it at all. Then again, you might not.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

jim <"sjedgingN0Sp"@m@mwt,net> wrote:
>Scott Dorsey wrote:
>
>> . I did
>> have to replace a number of brake lines due to external rust, but
>> when I cut them open they were nice and clean inside. So here was
>> thirty-year-old fluid (because I _know_ these bozos never changed
>> anything on any schedule), doing its job perfectly well.
>
>Do you believe this car never had any brake work that involve bleeding the
>brakes in 30 years?

It may have been bled a few times, but from the condition of the pads and
rotors the previous owners were not interested in doing any brake work
they could avoid. A full fluid change is a bit more dramatic than a bleed
but I agree that it's quite possible some fluid got exchanged now and then.

>> That's basically the way I think about it. If the system is perfectly
>> sealed, there's no real need to change it, but I worry about how well
>> sealed it really is.
>
>The original poster's mechanic is correct to suggest changing the brake
>lines. Regular use of the vehicle seems to help protect against corrosion to
>brake lines to some extent. It is not uncommon to have the brake lines pop
>after an car has been left sitting for a year. If you replace just the on
>that goes first then another will let loose.

This is absolutely true.

>> I'm currently having an inexplicable clutch issue that is clearly
>> related to the hydraulics. Changed out _everything_ over the course
>> of a couple years, including both cylinders and all the piping, and
>> I thought it had gone away until the warm weather started up and now
>> it's back again. Either air is mysteriously getting into the system
>> somewhere, or there's a particle somewhere in the system that is moving
>> around. I've flushed everything several times now.... may be related
>> to fluid breakdown, then again maybe it's not...
>
>Clutches are a little different than brakes. The way brakes are designed it
>isn't likely to ever get negative pressure in the system.

This is also true. However, in this vehicle it all comes from the same
reservoir... change one and you change the other.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 9 Mar 2009 11:32:09 -0400, (Scott Dorsey) wrote:

>Ashton Crusher > wrote:
>>
>>Interesting article. I ran across an article quoting Ford engineers
>>about the whole 'water in brake fluid' thing. In short, they have
>>studied it and found that the amount of water that's absorbed gets
>>absorbed early on and then stabilizes.
>
>Yes, this is clearly the case. Hopefully if the system stays sealed, the
>only water that gets absorbed is a tiny amount when the system is first
>filled.
>
>But, if the system isn't completely sealed, it will absorb some amount of
>water and then saturate pretty quickly. Then it will stay in this state
>for years.
>
>>Unless you keep opening the
>>system up they concluded that there was no reason to flush the system
>>other then flushing it when you did normal brake service for pads,
>>etc. It can't hurt to flush but some people are way too anal about
>>it.
>
>Yes, the severe service schedule on my '85 suggests doing it every five
>years. That sounds reasonable enough. You might get away with never doing
>it at all. Then again, you might not.

Though I don't do it, I sure would't argue against 5 years.
There is a lot of conflicting info, and I haven't seen any analysis
close to what you'll find on lube oil.
My son has pulled apart a lot of failed brake components, and always
finds the only serious corrosion is around the full circumference of
the pistons where they travels on the seals.
He considers every failure he has seen a seal failure, and attributes
nothing to fluid, and everything to seal quality and the quality of
the metals to resist corrosion and abrasion once the seals allow
intrusion of moisture and grit.
This makes sense to me, and the only way I can explain why my
Celebrity went 14 years and 190k miles with no brake issues except
pad/shoes and a set of rotors. I recall popping the MC lid only twice
to look at the fluid level.
OTOH, in looking about for this thread I saw Brembo caliper pistons
badly corroded after about 36k miles. Think it's a Chrysler model
forum.
http://www.srt8oc.com/forums/showthr...t=19635&page=2

Make of it what you will. I don't think changing fluid would have
helped this guy, but I might be wrong. For all I know Chrysler mixed
battery acid in the brake fluid at the factory.
Changing fluid shouldn't hurt if you don't snap off a bleeder or
overextend the MC piston.
If I ever got interested I'd get a pressure bleeder, and early on get
a coat of anti-seize on the outer threads of the bleeders where they
tend to rust solid onto the caliper/wheel cylinder.
To each his own.

--Vic

Chris F. wrote:
> It's worth noting that the brake lines on this car, run along the inside of
> the passenger compartment rather than along the underside. However, they
> have been disconnected and sitting all winter.... I will probably replace
> the lines anyway since I don't want to risk failure down the road.
>

If they have been disconnected for a winter, discussion over, you must
change them out. They will have rusted all to crap inside over the
winter.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00
'New' frame and everything else in '09. Some Canadian Bush Trip and
Build Photos: http://mikeromainjeeptrips.shutterfly.com