Prev: Car registration sequence that really shouldn't have been issued
Next: Sticky wheel?
From: Mrcheerful on 29 Jun 2010 18:03

"Bob Dodds" <13013dodds(a)gmail.com> wrote in message
news:fc78b73c-3d92-4f41-8ffa-89cf8b39de0a(a)u26g2000yqu.googlegroups.com...
> On 29 June, 21:26, Chris Whelan <cawhe...(a)prejudicentlworld.com>
> wrote:
>> On Tue, 29 Jun 2010 20:36:04 +0100, Paul wrote:
>>
>> [...]
>>
>> > And the stuff in the reservoir in theory never gets used, as its there
>> > to replace any lost by a leak...
>>
>> It's there primarily to account for the change in volume caused by the
>> friction materials wearing. For example. as the pads wear, the caliper
>> pistons move further out, and more fluid is needed to make up that space.
>>
>> The water is heavier than the brake fluid, so eventually finds it way to
>> the lowest part of the system, which in most conventional cars is the
>> rear wheel cylinders.
>>
>> Guess which part of the braking system is usually the first to succumb to
>> corrosion damage :-)
>>
>> Chris
>>
>> --
>> Remove prejudice to reply.
>
> OK if all this is true and this much moisture is added to the oil how
> come I've never had to remove oil from a hydraulic reservoir to make
> up for the water added? There must be a lot of water in the oil to
> become enough to cause all this corrosion.
>
> Bob
>

it only needs a tiny amount of water to rot the bore of a steel master
cylinder, I have seen dozens. completely unneeded and expensive, only
caused by lack of regular fluid changes and exacerbated by people that keep
brake fluid for umpteen years and use it to top up the master cylinder
(never necessary if the car is correctly maintained.)


From: Bob Dodds on 29 Jun 2010 18:14
On 29 June, 23:03, "Mrcheerful" <nbk...(a)hotmail.co.uk> wrote:
> "Bob Dodds" <13013do...(a)gmail.com> wrote in message
>
> news:fc78b73c-3d92-4f41-8ffa-89cf8b39de0a(a)u26g2000yqu.googlegroups.com...
>
>
>
>
>
> > On 29 June, 21:26, Chris Whelan <cawhe...(a)prejudicentlworld.com>
> > wrote:
> >> On Tue, 29 Jun 2010 20:36:04 +0100, Paul wrote:
>
> >> [...]
>
> >> > And the stuff in the reservoir in theory never gets used, as its there
> >> > to replace any lost by a leak...
>
> >> It's there primarily to account for the change in volume caused by the
> >> friction materials wearing. For example. as the pads wear, the caliper
> >> pistons move further out, and more fluid is needed to make up that space.
>
> >> The water is heavier than the brake fluid, so eventually finds it way to
> >> the lowest part of the system, which in most conventional cars is the
> >> rear wheel cylinders.
>
> >> Guess which part of the braking system is usually the first to succumb to
> >> corrosion damage :-)
>
> >> Chris
>
> >> --
> >> Remove prejudice to reply.
>
> > OK if all this is true and this much moisture is added to the oil how
> > come I've never had to remove oil from a hydraulic reservoir to make
> > up for the water added? There must be a lot of water in the oil to
> > become enough to cause all this corrosion.
>
> > Bob
>
> it only needs a tiny amount of water to rot the bore of a steel master
> cylinder, I have seen dozens.  completely unneeded and expensive, only
> caused by lack of regular fluid changes and exacerbated by people that keep
> brake fluid for umpteen years and use it to top up the master cylinder
> (never necessary if the car is correctly maintained.)- Hide quoted text -
>
> - Show quoted text -

OK I give in to people with more experience, it just seems strange to
me that a virtually sealed system can be affected at its remote ends 2
to 3 meters down a micro bore system by the tiny breather hole at the
reservoir which is sealed with a "rubber" relief valve.

Bob
From: Duncan Wood on 29 Jun 2010 18:26
On Tue, 29 Jun 2010 23:14:12 +0100, Bob Dodds <13013dodds(a)gmail.com> wrote:

> On 29 June, 23:03, "Mrcheerful" <nbk...(a)hotmail.co.uk> wrote:
>> "Bob Dodds" <13013do...(a)gmail.com> wrote in message
>>
>> news:fc78b73c-3d92-4f41-8ffa-89cf8b39de0a(a)u26g2000yqu.googlegroups.com...
>>
>>
>>
>>
>>
>> > On 29 June, 21:26, Chris Whelan <cawhe...(a)prejudicentlworld.com>
>> > wrote:
>> >> On Tue, 29 Jun 2010 20:36:04 +0100, Paul wrote:
>>
>> >> [...]
>>
>> >> > And the stuff in the reservoir in theory never gets used, as its
>> there
>> >> > to replace any lost by a leak...
>>
>> >> It's there primarily to account for the change in volume caused by
>> the
>> >> friction materials wearing. For example. as the pads wear, the
>> caliper
>> >> pistons move further out, and more fluid is needed to make up that
>> space.
>>
>> >> The water is heavier than the brake fluid, so eventually finds it
>> way to
>> >> the lowest part of the system, which in most conventional cars is the
>> >> rear wheel cylinders.
>>
>> >> Guess which part of the braking system is usually the first to
>> succumb to
>> >> corrosion damage :-)
>>
>> >> Chris
>>
>> >> --
>> >> Remove prejudice to reply.
>>
>> > OK if all this is true and this much moisture is added to the oil how
>> > come I've never had to remove oil from a hydraulic reservoir to make
>> > up for the water added? There must be a lot of water in the oil to
>> > become enough to cause all this corrosion.
>>
>> > Bob
>>
>> it only needs a tiny amount of water to rot the bore of a steel master
>> cylinder, I have seen dozens. completely unneeded and expensive, only
>> caused by lack of regular fluid changes and exacerbated by people that
>> keep
>> brake fluid for umpteen years and use it to top up the master cylinder
>> (never necessary if the car is correctly maintained.)- Hide quoted text
>> -
>>
>> - Show quoted text -
>
> OK I give in to people with more experience, it just seems strange to
> me that a virtually sealed system can be affected at its remote ends 2
> to 3 meters down a micro bore system by the tiny breather hole at the
> reservoir which is sealed with a "rubber" relief valve.
>
> Bob

I'd agree if I hadn't seen loads of them.

--
Duncan Wood
From: Duncan Wood on 29 Jun 2010 18:30
On Tue, 29 Jun 2010 23:02:51 +0100, Bob Dodds <13013dodds(a)gmail.com> wrote:

> On 29 June, 22:51, "Duncan Wood" <nntp...(a)dmx512.co.uk> wrote:
>> On Tue, 29 Jun 2010 22:45:47 +0100, Bob Dodds <13013do...(a)gmail.com>
>> wrote:
>> > On 29 June, 21:26, Chris Whelan <cawhe...(a)prejudicentlworld.com>
>> > wrote:
>> >> On Tue, 29 Jun 2010 20:36:04 +0100, Paul wrote:
>>
>> >> [...]
>>
>> >> > And the stuff in the reservoir in theory never gets used, as its
>> there
>> >> > to replace any lost by a leak...
>>
>> >> It's there primarily to account for the change in volume caused by
>> the
>> >> friction materials wearing. For example. as the pads wear, the
>> caliper
>> >> pistons move further out, and more fluid is needed to make up that
>> >> space.
>>
>> >> The water is heavier than the brake fluid, so eventually finds it
>> way to
>> >> the lowest part of the system, which in most conventional cars is the
>> >> rear wheel cylinders.
>>
>> >> Guess which part of the braking system is usually the first to
>> succumb >> to
>> >> corrosion damage :-)
>>
>> >> Chris
>>
>> >> --
>> >> Remove prejudice to reply.
>>
>> > OK if all this is true and this much moisture is added to the oil how
>> > come I've never had to remove oil from a hydraulic reservoir to make
>> > up for the water added? There must be a lot of water in the oil to
>> > become enough to cause all this corrosion.
>>
>> > Bob
>>
>> They're miscible & it doesn't take very much.
>>
>> --
>> Duncan Wood- Hide quoted text -
>>
>> - Show quoted text -
>
> That makes it more puzzling by being miscible you would need a lot
> more moisture to contaminate the oil. If they stayed separated and as
> said previously the water migrated to the lowest point you would need
> less contamination to affect the caliper pistons.
>
> Bob

I think that's the only bit that corrodes, the reason silicone iisn't
popular is that it isn't miscible & any water does end up in the
piston/hot bit.

--
Duncan Wood
From: Mrcheerful on 29 Jun 2010 18:32

"Bob Dodds" <13013dodds(a)gmail.com> wrote in message
news:b7600c8a-6ef6-470d-8433-5e6dd1b0fca6(a)e5g2000yqn.googlegroups.com...
On 29 June, 23:03, "Mrcheerful" <nbk...(a)hotmail.co.uk> wrote:
> "Bob Dodds" <13013do...(a)gmail.com> wrote in message
>
> news:fc78b73c-3d92-4f41-8ffa-89cf8b39de0a(a)u26g2000yqu.googlegroups.com...
>
>
>
>
>
> > On 29 June, 21:26, Chris Whelan <cawhe...(a)prejudicentlworld.com>
> > wrote:
> >> On Tue, 29 Jun 2010 20:36:04 +0100, Paul wrote:
>
> >> [...]
>
> >> > And the stuff in the reservoir in theory never gets used, as its
> >> > there
> >> > to replace any lost by a leak...
>
> >> It's there primarily to account for the change in volume caused by the
> >> friction materials wearing. For example. as the pads wear, the caliper
> >> pistons move further out, and more fluid is needed to make up that
> >> space.
>
> >> The water is heavier than the brake fluid, so eventually finds it way
> >> to
> >> the lowest part of the system, which in most conventional cars is the
> >> rear wheel cylinders.
>
> >> Guess which part of the braking system is usually the first to succumb
> >> to
> >> corrosion damage :-)
>
> >> Chris
>
> >> --
> >> Remove prejudice to reply.
>
> > OK if all this is true and this much moisture is added to the oil how
> > come I've never had to remove oil from a hydraulic reservoir to make
> > up for the water added? There must be a lot of water in the oil to
> > become enough to cause all this corrosion.
>
> > Bob
>
> it only needs a tiny amount of water to rot the bore of a steel master
> cylinder, I have seen dozens. completely unneeded and expensive, only
> caused by lack of regular fluid changes and exacerbated by people that
> keep
> brake fluid for umpteen years and use it to top up the master cylinder
> (never necessary if the car is correctly maintained.)- Hide quoted text -
>
> - Show quoted text -

OK I give in to people with more experience, it just seems strange to
me that a virtually sealed system can be affected at its remote ends 2
to 3 meters down a micro bore system by the tiny breather hole at the
reservoir which is sealed with a "rubber" relief valve.

Bob

the fluid at the 'bottom' end seems to draw in dampness past the seals in
the cylinder or caliper, this is easily seen by the discolouration of the
fluid, when you change it the fluid almost immediately changes colour, long
before the fresh fluid could get there. at the top moisture pulls past the
breather cap and seems to accumulate at the bottom of the master cylinder
bore. happily the dampness rarely seems to effect abs units which are the
furthest from moisture entry points.


First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4 5
Prev: Car registration sequence that really shouldn't have been issued
Next: Sticky wheel?