DOT Fluid

On 6/17/2020 11:48 PM, John B. wrote:

Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?
--
cheers,

John B.


DOT 3/4 brake fluid is hygroscopic which is a problem. For
vintage autos and motorcycles an annual 100% fluid change is
good practice to prevent rust in the master cylinder and
lines. Bicycles commonly have open vent systems which suck
moisture from the air and so could reasonably reduce braking
effectiveness. (I don't know a case of that)

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Thu, 18 Jun 2020 09:22:03 +0200, Rolf Mantel
wrote:

Am 18.06.2020 um 08:32 schrieb John B.:
On Wed, 17 Jun 2020 23:07:14 -0700 (PDT), wrote:

On Thursday, June 18, 2020 at 6:48:38 AM UTC+2, John B. wrote:
Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?

Never heard of that requirement. In my car is is changed every 2 years.

Somebody here, talking about bicycle disk brakes mentioned that DOT
liquid must be changed annually while mineral oil did not require
this.

As the DOT brake oil in my pickup truck has been there for probably 20
years without being changed I asked the question.

Outch. DOT brake fluid (as opposed to mineral oil) is strongly
hygroscopic, i.e. it absorbs water, changing it properties
significantly. Therefore, DOT brake fluid must be changed regularly; in
Europe, the age of brake fluid is one of the safety checks that need to
be documented every 2 years, or the car will be taken out of service.
If your truck was 40 years old instead of 20, it might still have the
old mineral oil that doesn't need changing

In cars and motorbikes, the exchange interval is every two years
irrespective of mileage. Possibly, in bicycles it has to be changed
more often due to the smaller brake fluid container, or possibly the
bike manufacturers are just more cautios if they stipulate annual change.

Given that bicycles have significantly lower problems with overheating,
mineral oil seems more appropriate than DOT fluid for bicycle brakes.

Rolf

While I don't doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.

It must be a European thing.
--
cheers,

John B.

On 6/18/2020 5:53 PM, John B. wrote:
On Thu, 18 Jun 2020 09:22:03 +0200, Rolf Mantel
wrote:

Am 18.06.2020 um 08:32 schrieb John B.:
On Wed, 17 Jun 2020 23:07:14 -0700 (PDT), wrote:

On Thursday, June 18, 2020 at 6:48:38 AM UTC+2, John B. wrote:
Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?

Never heard of that requirement. In my car is is changed every 2 years.

Somebody here, talking about bicycle disk brakes mentioned that DOT
liquid must be changed annually while mineral oil did not require
this.

As the DOT brake oil in my pickup truck has been there for probably 20
years without being changed I asked the question.

Outch. DOT brake fluid (as opposed to mineral oil) is strongly
hygroscopic, i.e. it absorbs water, changing it properties
significantly. Therefore, DOT brake fluid must be changed regularly; in
Europe, the age of brake fluid is one of the safety checks that need to
be documented every 2 years, or the car will be taken out of service.
If your truck was 40 years old instead of 20, it might still have the
old mineral oil that doesn't need changing

In cars and motorbikes, the exchange interval is every two years
irrespective of mileage. Possibly, in bicycles it has to be changed
more often due to the smaller brake fluid container, or possibly the
bike manufacturers are just more cautios if they stipulate annual change.

Given that bicycles have significantly lower problems with overheating,
mineral oil seems more appropriate than DOT fluid for bicycle brakes.

Rolf

While I don't doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.

It must be a European thing.
--
cheers,

John B.


I do regularly every spring.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Thu, 18 Jun 2020 17:56:57 -0500, AMuzi wrote:

On 6/18/2020 5:53 PM, John B. wrote:
On Thu, 18 Jun 2020 09:22:03 +0200, Rolf Mantel
wrote:

Am 18.06.2020 um 08:32 schrieb John B.:
On Wed, 17 Jun 2020 23:07:14 -0700 (PDT), wrote:

On Thursday, June 18, 2020 at 6:48:38 AM UTC+2, John B. wrote:
Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?

Never heard of that requirement. In my car is is changed every 2 years.

Somebody here, talking about bicycle disk brakes mentioned that DOT
liquid must be changed annually while mineral oil did not require
this.

As the DOT brake oil in my pickup truck has been there for probably 20
years without being changed I asked the question.

Outch. DOT brake fluid (as opposed to mineral oil) is strongly
hygroscopic, i.e. it absorbs water, changing it properties
significantly. Therefore, DOT brake fluid must be changed regularly; in
Europe, the age of brake fluid is one of the safety checks that need to
be documented every 2 years, or the car will be taken out of service.
If your truck was 40 years old instead of 20, it might still have the
old mineral oil that doesn't need changing

In cars and motorbikes, the exchange interval is every two years
irrespective of mileage. Possibly, in bicycles it has to be changed
more often due to the smaller brake fluid container, or possibly the
bike manufacturers are just more cautios if they stipulate annual change.

Given that bicycles have significantly lower problems with overheating,
mineral oil seems more appropriate than DOT fluid for bicycle brakes.

Rolf

While I don't doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.

It must be a European thing.
--
cheers,

John B.


I do regularly every spring.

O.K. One guy in 70 man years :-)
--
cheers,

John B.

On Thursday, June 18, 2020 at 1:28:27 AM UTC-7, Tosspot wrote:
On 18/06/2020 08:32, John B. wrote:
On Wed, 17 Jun 2020 23:07:14 -0700 (PDT), wrote:

On Thursday, June 18, 2020 at 6:48:38 AM UTC+2, John B. wrote:
Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?
--
cheers,

John B.

Never heard of that requirement. In my car is is changed every 2 years.

Lou

Somebody here, talking about bicycle disk brakes mentioned that DOT
liquid must be changed annually while mineral oil did not require
this.

As the DOT brake oil in my pickup truck has been there for probably 20
years without being changed I asked the question.

Reading, after I posted up there--^ DOT 3,4 and 5.1 are hygroscopic
polyputtheketteon, DOT 5 is silicone and isn't.

Soo...hygroscopic ones need replacing, silicone ones last a lot longer.

So if it has silicone it will probably be ok, the issue is moisture
pools at the bottom of the system potentially causing rot.

Hygroscopic or not it is extremely difficult to get water into a sealed brake system.

On 6/18/2020 6:01 PM, John B. wrote:
On Thu, 18 Jun 2020 17:56:57 -0500, AMuzi wrote:

On 6/18/2020 5:53 PM, John B. wrote:
On Thu, 18 Jun 2020 09:22:03 +0200, Rolf Mantel
wrote:

Am 18.06.2020 um 08:32 schrieb John B.:
On Wed, 17 Jun 2020 23:07:14 -0700 (PDT), wrote:

On Thursday, June 18, 2020 at 6:48:38 AM UTC+2, John B. wrote:
Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?

Never heard of that requirement. In my car is is changed every 2 years.

Somebody here, talking about bicycle disk brakes mentioned that DOT
liquid must be changed annually while mineral oil did not require
this.

As the DOT brake oil in my pickup truck has been there for probably 20
years without being changed I asked the question.

Outch. DOT brake fluid (as opposed to mineral oil) is strongly
hygroscopic, i.e. it absorbs water, changing it properties
significantly. Therefore, DOT brake fluid must be changed regularly; in
Europe, the age of brake fluid is one of the safety checks that need to
be documented every 2 years, or the car will be taken out of service.
If your truck was 40 years old instead of 20, it might still have the
old mineral oil that doesn't need changing

In cars and motorbikes, the exchange interval is every two years
irrespective of mileage. Possibly, in bicycles it has to be changed
more often due to the smaller brake fluid container, or possibly the
bike manufacturers are just more cautios if they stipulate annual change.

Given that bicycles have significantly lower problems with overheating,
mineral oil seems more appropriate than DOT fluid for bicycle brakes.

Rolf

While I don't doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.

It must be a European thing.
--
cheers,

John B.


I do regularly every spring.

O.K. One guy in 70 man years :-)

It's cheap as compared to a burst brake line at speed or a
rusted master cylinder. If you have experienced neither then
good for you; keep doing what you do. As shall I.


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

While I don'tÂ* doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.


The manual for my 2009 Honda Fit calls for changing the brake fluid every three
years.

On 6/18/2020 6:53 PM, John B. wrote:
On Thu, 18 Jun 2020 09:22:03 +0200, Rolf Mantel
wrote:

Am 18.06.2020 um 08:32 schrieb John B.:
On Wed, 17 Jun 2020 23:07:14 -0700 (PDT), wrote:

On Thursday, June 18, 2020 at 6:48:38 AM UTC+2, John B. wrote:
Someone cautioned that DOT brake fluid, in bicycle disk brakes, should
be changed annually.
Is this correct? A requirement of the disk makers? Or ?

Never heard of that requirement. In my car is is changed every 2 years.

Somebody here, talking about bicycle disk brakes mentioned that DOT
liquid must be changed annually while mineral oil did not require
this.

As the DOT brake oil in my pickup truck has been there for probably 20
years without being changed I asked the question.

Outch. DOT brake fluid (as opposed to mineral oil) is strongly
hygroscopic, i.e. it absorbs water, changing it properties
significantly. Therefore, DOT brake fluid must be changed regularly; in
Europe, the age of brake fluid is one of the safety checks that need to
be documented every 2 years, or the car will be taken out of service.
If your truck was 40 years old instead of 20, it might still have the
old mineral oil that doesn't need changing

In cars and motorbikes, the exchange interval is every two years
irrespective of mileage. Possibly, in bicycles it has to be changed
more often due to the smaller brake fluid container, or possibly the
bike manufacturers are just more cautios if they stipulate annual change.

Given that bicycles have significantly lower problems with overheating,
mineral oil seems more appropriate than DOT fluid for bicycle brakes.

Rolf

While I don't doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.

It must be a European thing.

I didn't change the brake fluid on our previous car. I believe that's
why I had to eventually replace a sticking front brake caliper.

--
- Frank Krygowski

On Thu, 18 Jun 2020 20:47:00 -0400, Bertrand
wrote:

While I don't* doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service
manual and there is no mention of changing the brake fluid.


The manual for my 2009 Honda Fit calls for changing the brake fluid every three
years.

I just located an on line references to changing Honda brake and ATF
fluid and yes the dealer does recommend changing brake fluid every
30,000 miles or 3 years, depending on what site I read. They also
recommend changing the ATF fluid and again I found a 30,000 mile
reference but I don't know whether that is the official Honda figure
and I also find reference to changing the radiator coo lent with,
again, unofficial mention of a 30,000 mile interval.

Apparently the only liquid that you don't have to specifically change
is the gasoline :-)
--
cheers,

John B.

On Fri, 19 Jun 2020 05:53:05 +0700, John B. wrote:



While I don't doubt you I have never, in the 70 years or so that I've
been fooling about with motor vehicles heard of anyone changing brake
fluid per some schedule and I just checked the Honda HR-V service manual
and there is no mention of changing the brake fluid.

It must be a European thing.

Err, did you ever have it serviced under one of those routine services
based on distance and time?

Whilst I've never performed a change, I've always found it easier on my
time to just pay the local garage, in the past and the dealer now, to
carry out these services and some of them have invoiced brake fluid.