Several online sources (auto parts store , garages ) have recommended flushing and
replacing brake fluid at intervals of 24 months / 24000 miles citing fluid contamination
andmoisture retention as primary reasons....and to purge any air as
secondary reasons, unless the system has been opened.

I also looked at the Owners manual for two different GM
vehicles, a Chiltons manual and a factory service guide.
None of these specified periodic brake system flushing although
the service guide gave some very general guidelines.

However, not a whole lot of shops advertise the need for
this procedure... If you take your car into a Jiffy Lube (just for
example), they will replace oil, filters, belts, transmission fluid,
but never say a word about brake fluid. If it was that necessary
and part of a recommended service program, it seems to me that
a lot more tune and lube places would be advertising this service.

So what is the truth here ??? Do mechanics and engineers
see a need for regular, planned brake fluid changes ?? Is this marketing
hype?? Is the difference somewhere in the middle ??

Appreciate your thoughts and wisdom on this matter !!

Thanks in advance !!

Peter









ps.... raybestos has a brake system learning center at
http://www.raybestos.com/OnLineTraining/abs-177.htm

It also has some training programs.... I could only find
a backdoor link at http://www.raybestos.com/OnLineTraining/abs-177.htm
but this might help someone.

>what is the truth here ?

24mos/24Kmi seems reasonable. I've always gone by what the fluid in the
master cylinder looks like. If not clear, I do a gravity flush with new
fluid. Brake fluid is not expensive given the small amount in the
system. Safety is the primary concern and fresh fluid is cheap
insurance.

Dave S(Texas)

I've also read that regular flushing will extend the life of some very
expensive anti-lock components. I've been doing this to my cars and trucks
since the "70's" and I've never had to repair or replace a wheel cylinder or
caliper, and I usually keep a vehicle around ten years.

Al

<putt@webtv.net> wrote in message
news:16568-4523CCEA-915@storefull-3271.bay.webtv.net...

"Peter" <Peter@spamtrap.net> wrote in message
news:s487i2pavj8i5grc18t73c90m4gj9imnji@4ax.com...

I've never done a "change" per se, but have bled brake lines and added new
fluid. Don't know if changing helps, but certainly can't hurt.

When we service fleet vehicles we did so at two years or 50K, WOF.
Problems stems from moisture, not particulate, contamination

mike


<putt@webtv.net> wrote in message
news:16568-4523CCEA-915@storefull-3271.bay.webtv.net...

Peter wrote:

For no apparently good reason some auto makers suggest changing the
brake fluid every two years while others claim it is good for life. I
know that Volvo, VW and Honda for example do call for periodic changes.

Personally, I do it on all our vehicles as it is inexpensive and makes
plenty of sense.

John

Try DOT #5 next time, and eliminate the need for further changes, if you
keep your new vehicles longer than the average three of four years, WBMA


mike hunt


"John Horner" <jthorner@yahoo.com> wrote in message
news:9dcVg.28971$Oh3.15403@trnddc04...

On Thu, 5 Oct 2006 14:57:54 -0400, "Mike Hunter" <mikehunt2@mailcity.com> wrote:

There were definite warnings AGAINST using DOT5 in a 1990 Olds
Silhouette and a 2002 Monte Carlo (ABS)

Also, it seems like DOT 3 - 4 and DOT 5 are incompatible with each other,
requiring a complete system flush when switching from one to the other. This is
just presented as general information.

Peter

Peter wrote:

They are imcompatible with one another, and also there's some concern
about DOT 5 cavitating in an ABS control unit which is probably the
reason for the warnings. Supposedly there's a DOT 5.1 which is
compatible with DOT 3/4 (i.e. not silicone based) but meets the
performance specs of DOT 5 but I have not tried it so I can't give an
official recommendation.

The official word from most of the mfgrs. is that brake fluid changes
are not necessary, that the brake system if left sealed will not absorb
enough moisture over its lifetime to cause corrosion, and in fact
changing the brake fluid may cause more harm than good because of the
possibility of introducing dirt and contaminants into the ABS HCU.
However, the caveat is that most of them consider the "lifetime" to be
only ten years. So you pays your money and you takes your pick. I
personally would go ahead and flush; however, be smart about it - keep
everything scrupulously clean when you do so; might even be a good idea
to clean out the reservoir before beginning (use turkey baster to
empty.) When replacing pads, open the bleeder screw as you push the
pads back in as you do not want to "back flush" any goo into the HCU.
However, if you plan on wearing the vehicle completely out within ten
years, it's probably a waste of time, even though it feels like a lack
of proper maintenance.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

"Nate Nagel" <njnagel@flycast.net> wrote in message

This is painting the manufacturers with a bit of a broad brush.

Moisture doesnt penetrate rubber hoses and get into the brake fluid. But
even with the better designed brake fluid tanks, moisture may eventually
contaminate the system.

With a lot of cars, brakes will be changed every few years and we would hope
that the line would be flushed and bled.

I have a Teves system in my Reatta, and we are warned to flush the system
every two years. It is preventative maintenance. If you abuse a Teves
system and get corrosion, you are looking at $1000-$2000 to get it back
in shape. A person would have to be a fool to neglect
maintenance in such a system.

How many ordinary braking systems have I rebuilt to find the cylinders
pitted and full of 'mud'? Lots of them. If
changing fluid helps prevent brake failure, and improves safety, it costs
little enough.