to change the brake fluid or not to change? - carnie104b
Hi!, I just got my VW Passat back from a 50K service and change of cambelt, water pump etc... the dealership has been at me for a couple of years now to change the brake fluid.

Does anyone have any views on this as I am not sure whether this is just another rip off scheme from manuacturers to get more dosh!!

Any comments would be welcomed.

{made non make/model specific as several makes/models are being discussed. Have included OP's car details in main post though for reference.}

Edited by Dynamic Dave on 25/01/2009 at 12:47

to change the brake fluid or not to change? - Dynamic Dave
Your brake system isn't 100% sealed. Brake fluid absorbs moisture over a period of time, resulting in a reduction in braking efficency.

I don't know how much they're asking you to change it, but Vauxhall last charged me something like £25. That works out at just over a £1 a month as Vauxhall recommend it be changed every 2 yrs. No brainer really for peace of mind, IMHO.
to change the brake fluid or not to change? - mikeyb
I had my partners done at the last service - think VW charged me £40 - car was 2 yrs 4 months old. Not sure if it really needed doing, but as my kids go around in it then for £40 I didnt have to think twice about it.
to change the brake fluid or not to change? - carnie104b
Hmmm.. when you put it like it then I think it may be a good idea.

Thanks!
to change the brake fluid or not to change? - steve_earwig
It's not just a reduction in efficiency - the water in the lines can boil under certain conditions (e.g. going down a steep hill) and leave you with air (well, steam really) locks, with not-so-hilarious consequencies.

Incidently I live in Croatia and they now have a brake fluid test in their equivalent of the MOT.
to change the brake fluid or not to change? - carnie104b
thanks for your response - they offered me a "special" offer of £89.00!! and recommend that this is caried out every 2 years.
to change the brake fluid or not to change? - doctorchris
DD says it all.
Many years ago I drove my Triumph Herald down a mountain, the water in the brake fluid boiled and I had no brakes. Scarey enough for me to believe in changing brake fluid at least every 3 years.
to change the brake fluid or not to change? - steve_earwig
Gah! Can't edit it now either...must learn to type faster...
to change the brake fluid or not to change? - Pendlebury
As above really carnie - my advice is get it done and get it re-done every 2 years (although for some reason Honda state 3 years in the manual). The other problem is that it can get very dirty and as has been already said it can get water ingress and cause safety problems or damage your abs pump - and when you are paying £1K to replace that then the investment of £40-50 would be worth it.
to change the brake fluid or not to change? - Halmer
Doesn't the ABS system deteriorate or something unless you change the fluid periodically?
to change the brake fluid or not to change? - madf
In theory as ABS vales are s/steel they should not.
In practice, dirt and grime will possibly lead to valve pitting and or accumulation of residues.I believe.


As posted above don't change, save £40 and buy a new ABS unit for £1000 : it's a nobrainer.


Edited by madf on 23/01/2009 at 19:36

to change the brake fluid or not to change? - the swiss tony
As posted above don't change save £40 and have brake failure, write the car off, and maybe kill someone..... deffo a no brainer!

to change the brake fluid or not to change? - carnie104b
Thanks to all that have posted a response, it really has meade me think twice about this - I wasn't going to bother but now i am on the change I think!!!

Cheers guys!
to change the brake fluid or not to change? - Stuartli
On the other hand, my Bora's brake fluid has never been changed (I've had it nearly six years now and it was registered in November 1999) and the braking performance is definitely no worse than when I acquired it...:-)

It certainly sails through its MOT on braking standards.


to change the brake fluid or not to change? - Woodspeed
Day to day stopping, and a MOT test will not show any deterioration. But you try doing 2 high speed stops (the second about 1 minute after the first) and you will have the pedal going into the floor as the moisture in the fluid (and believe me after 6 years you WILL have water) boils and vaporises - especially if the pads are worn so the tremendous heat from the disc goes straight through the calliper into the fluid.
Most manufacturers specify a 2 year period to change, and also the instant gravy that comes out is gritty and can jam valves in the ABS valve chamber which has fine tolerances.
Not studied the specs yet but I noticed Comma now make a SYNTHETIC DOT 4 brake fluid which is mixable with existing fluids. I believe this is not hygroscopic like non synthetic, but I will still flush every 2 years. £89 is expensive. Push them for a cheaper price and tell them " as it is only a 10 minute job" which it is and 2 litres of fluid cost £10 at the most (factors).
to change the brake fluid or not to change? - Stuartli
especially if the pads are worn>>


About three months old...:-)

I would certainly notice any deterioration in braking performance if it arose; I wouldn't hesitate, either, to have it changed if deemed necessary..

As for synthetic brake fluid, VW makes it clear that you must meet a particular brake fluid standard and I do, in fact, have a tin bought for topping up purposes. However, it's never been opened as the level hasn't varied from the line on the brake fluid chamber since I first acquired the car in early 2003.
to change the brake fluid or not to change? - Dynamic Dave
the braking performance is definitely no worse than when I acquired it...:-)


You've probably not noticed as the performance drop off has been gradual and not instant. I bet you would notice an immediate difference if you did have it changed.
to change the brake fluid or not to change? - steve_earwig
When they tested the brake fluid in my 10 year old Peugeot (see above) it occured to me I'd never changed the fluid in 4 years of ownership (mainly because when the guy took the cap off it was black...), it passed but I changed it anyway, thinking the whole time how I hate doing jobs on cars that don't make any difference to how they drive. Afterwards I was wondering how I didn't notice they were so bad before I did it!
to change the brake fluid or not to change? - Buster Cambelt
If in doubt change it, brake fluid is hydroscopic and deteriorates over time. Changing it could save your life.
to change the brake fluid or not to change? - quizman
I'm not sure about brake fluid changes, so I bought a Gunsons brake fluid tester. You dip it in the brake fluid, press a button and either a red, amber, or green light comes on.
I tried it first on a builder's Transit van, the hole in the reservoir was too small to get the tester in. So I tried it in my Passat, the hole was big enough but there was a sieve in the neck of the reservoir which would not come out.
So that was a waste of money!

I've spoken to many people about brake fluid changing and all have never heard of it being done on their cars. How many crashed cars do you see at the bottom of steep hills?
to change the brake fluid or not to change? - Altea Ego
All this "change it it could save your life"

has anyone ever died from an accident in the last 10 years caused by brake fluid boiling?

I have NEVER EVER had my brake fluid changed in the last 37 years of driving

Boiling brake fluid is a myth.
to change the brake fluid or not to change? - jbif
... I have NEVER EVER had my brake fluid changed in the last 37 years of driving .. >>


American companies agree with you:
www.babcox.com/editorial/bf/bf50412.htm
" .. Statements made by the "Big 3" domestic OEM manufacturers that the brake fluid in their vehicles lasts the life of the vehicle ..
...One of the task force members involved with the OEMs found out one of the OEMs did a study using test fleets comprised of thousands of vehicles from various locations that were approximately 8 years old. They tested the brake fluid for moisture and discovered an average of less than one percent over the entire fleet. .. ... "

www.brakestrips.net/tech_myth_stopper.htm
" ... Then there's the mistaken belief, now earning the distinction of ?urban legend,? that water is brake fluid's worst enemy and the slightest trace of it demands an immediate system flush or dire things might happen. So ingrained is this unwarranted fear, many costly flushes are needlessly performed and any unused fluid promptly discarded lest it absorb water while awaiting a future top-off.
Now, new technology and standards are finally putting the decades-old moisture myth to rest. Especially since today's Anti-Lock Brake Systems and brake fluids are designed to reduce or eliminate moisture related problems. In fact, GM, Ford and Chrysler have no recommendation for brake fluid service based on moisture because it's not considered a safety threat or service issue. ... "

Edited by jbif on 24/01/2009 at 12:07

to change the brake fluid or not to change? - George Porge
Testing the reservoir is not a good indication of brake fluid "stregnth" The dirtiest fluid will be at the calipers, the in / out movement of the pistons take tiny amounts of debris and water inside every time you brake. The fluid degrades and the boiling point lowers.

This is supposed to be a forum for motoring enthusiast, not somewhere to preach bad practices for all the WORLD to see.


to change the brake fluid or not to change? - Altea Ego
This is supposed to be a forum for motoring enthusiast not somewhere to preach bad
practices for all the WORLD to see.


and the ideal place for motoring enthusiats to debunk myths to the world..

Now dox, have you ever had boiling brake fluid? any of your mates? (and brake fade IS NOT an exclusive indication of boiling brake fluid)
to change the brake fluid or not to change? - Hamsafar
I change my brake fluid whenever I replace the pads, as it takes about 10 minutes and costs about £4. It also means that when I undo the nipples to shoot some fluid out when retracting the new pads, I don't have to be too judicious as I know it will all be replaced in a few minutes. The new fluid always looks much clearer and less yellow than the old so there is obviously some difference.
to change the brake fluid or not to change? - madux
You can drive for years on the same brake fluid - but try descending a steep alpine pass for a few miles, as I did. 1 in 4 for about ten minutes, in second gear but using the brakes too
then all of a sudden - No brakes! That was frightening. Pads were a year old, don't know how old the fluid was but I had the same car in the UK for several more years without changing the brake fluid and had no problems. Maybe it only happens in extreme circumstances?
to change the brake fluid or not to change? - George Porge
Now dox have you ever had boiling brake fluid? any of your mates? (and brake
fade IS NOT an exclusive indication of boiling brake fluid)


No, because I change fluids as the manufacturer states.

Its not the first time we've dissaggreed on this subject either.

The next time you look in your mirror and the 20+ year old motor is sat near your bumper with the original fluid in the brake lines, its because he's listened to someone like yourself, it might stop, might not........................
to change the brake fluid or not to change? - steve_earwig
>Boiling brake fluid is a myth.

Apart from the two examples given above of course.

That aside, I'm serious about what I said happened when I changed my brake fluid. Ok, the car's 10 years old and I've no idea if it's ever been changed before but the pedal wasn't particularly spongy and no air came out the lines, they just worked a hell of a lot better after. Maybe it's not absolutly essential to do it every 2 or 3 years as the manufacturers suggest (unless you live in the Alps) but it's not something I'll be neglecting again.
to change the brake fluid or not to change? - Altea Ego
what two examples? They were examples of Brake fade. NOT boiling brake fluid. Brake fade has many causes usually to do with pads and disks

Example.

We took a capri RS3100 round castle combe. New brake fluid? nope at least 4 years old. The brakes failed.

reason? the pads got so hot they glazed then broke up then fell out. The brakes were so hot they couldnt be worked on for two hours. Brake fluid boiled? nope.
to change the brake fluid or not to change? - bathtub tom
>>Boiling brake fluid is a myth

Not in my experience.
I was driving hard down the old A2, braking heavily at the approach to roundabouts until at one, the brake pedal hit the floor. I survived the roundabout and pulled into a layby just past it. After five minutes I had a fairly solid pedal. I bought some fluid and flushed some through. It was fine.

A colleague experienced a very similar failure. He changed his brake fluid. It never happened again!
to change the brake fluid or not to change? - Altea Ego
did you do exactly the same high speed run again immediately after changing the fluid to prove it? did your colleague?


Edited by Altea Ego on 24/01/2009 at 16:48

to change the brake fluid or not to change? - jbif
... This is supposed to be a forum for motoring enthusiast, not somewhere to preach bad practices for all the WORLD to see. ...


Precisely. The link I posted says:

" .. The issue of brake fluid testing came under the scrutiny of the Maintenance Services Task Force of the AMRA (Automotive Maintenance and Repair Association) .... The task force was represented by members from the auto service industry, equipment manufacturers, parts manufacturers, education and the scientific community. .."

The conclusions of that US task force were:
" .... the task force adopted the following in regards to when to recommend brake fluid flushing and has incorporated them in to a Motorist Assurance Program's (MAP) Uniform Inspection and Communication Standards:
SUGGEST testing brake fluid at OE-recommended brake system inspection service intervals to insure copper content is below 200 ppm.
REQUIRE brake fluid replacement if copper content exceeds 200 ppm.
SUGGEST brake fluid replacement at vehicle-specific OE replacement intervals(if they exist). .."

[CAPITALs used are quoted as from the report]

Now, Dox, what do you base your claims on?
to change the brake fluid or not to change? - George Porge
Now Dox what do you base your claims on?


Manufacturers recommendations, I change the oil too even though it still slips through my fingers after the prescribed period / mileage and coolant too even though it still tastes ok

I've seen plenty of filthy brake fluid, and seen grit damage to piston seals and bores.


to change the brake fluid or not to change? - martint123
As stated, it absorbs water.

When I recently changed my seals and boots all round on my brake calipers, the brown gunge behind the pistons and rust at the bottom of the cylinders convinced me that changing brake fluid is worthwhile. Far cheaper than new calipers all round after (fill in the box) [xxxxx] miles.
Cheaper than new pistons that I needed for sure.
to change the brake fluid or not to change? - Fullchat
ABS pumps like clean fluid. Now they don't come cheap!
to change the brake fluid or not to change? - carnie104b
Having read all the comments, which again I thank you for, a thought comes to mind. If the changing of brake fluid was a reasonably essential part of preventive maintenance, surely Insurers and M.O.T./DVLA would be requesting proof that this work has been carried out???
to change the brake fluid or not to change? - steve_earwig
As above, it's part of the MOT (well, ok, teknicki pregled) here. Then again I wouldn't trust some of the people here not to top it up with pig's urine.

I can't remember my dad ever changing brake fluid, then I can't remember him changing air or fuel filters either...

Edited by steve_earwig on 24/01/2009 at 16:59

to change the brake fluid or not to change? - George Porge
If the changing of brake fluid was a reasonably essential part of preventive maintenance
surely Insurers and M.O.T./DVLA would be requesting proof that this work has been carried out???


One day it just might be part of legislation, especially if the powers that be read the awesome advice given here.

I've got an old pair of calipers in the shed, I'll try and photo the scoring after 6 years use and 120K miles, fully serviced including BFCs, if I can be bothered
to change the brake fluid or not to change? - Altea Ego
I've got an old pair of calipers in the shed I'll try and photo the
scoring after 6 years use and 120K miles fully serviced including BFCs if I can
be bothered


scoring? well not much point changing the fluid then was there.

Answer me this

Our lease company keep the cars for 4 years, they never have the fluid changed. Now in this age of corporate responsibility and threats of being sued, why do they not do it? Hmm?

to change the brake fluid or not to change? - Armitage Shanks {p}
SFAIK garages can test a sample of the brake fluid and determine its boiling point; this is a guide to how much moisture is in it and thus give an indication of whether a change is necessary or not.
to change the brake fluid or not to change? - George Porge
How bad would they have been if the fluid had never been changed, leaking maybe?

I used to drive company vans, their policy was not to change the cambelts, they got away with it most of the time, they did'nt with my astra derv, snapped at 100K.

How long will your engine last without oil changes? PD diesel yes?

It'll only take one test case (or legislation) to change fleet managers attitudes to BFCs (and other corner cutting).
to change the brake fluid or not to change? - whoopwhoop
Our lease company keep the cars for 4 years they never have the fluid changed.
Now in this age of corporate responsibility and threats of being sued why do they
not do it? Hmm?


Answer me this.

Our lease company (the UK's largest in terms of number of vehicles on-fleet so mine's bigger than yours!) also keep their cars up to 4 years and *do* change the fluid at 2 years. Now in this age of cost control and slim profit margins why do they do it?

Hmmmmmmmmm.

(* and no, they don't pass on maint costs to employer - it's a "maint inc" lease.
to change the brake fluid or not to change? - brian doyle
Here is some more evidence. Below is a direct quote from Renault workshop manual MR293 section 30-13. This manual is for the Renault 19 and dates from circa 1988. The fluid type for this car is Dot 3 or Dot 4. The emphasis in caps is Renault's not mine.

"BRAKE FLUID CHANGE PERIODS

The brake fluids now used are subject to a slight deterioration, during their first few months of use, in that they absorb a small amount of water. Following this the water content stabilises.

As this slight deterioration takes place very early in the life of the fluid, braking systems are designed to take account of the fluid in this condition and therefore A SYSTEMATIC REPLACEMENT OF THE BRAKE FLUID IS NO LONGER NECESSARY

Furthemore, the design of our braking systems, in particular our disc brake units (hollow pistons that transmit very little heat, a small amount of fluid in the caliper cylinder, sliding calipers to avoid the necessity for a reserve of fluid in the hottest part of the wheel) avoids, as far as possible, risk of vapour lock, even when the brakes are intensively used (under mountain driving conditions).

Consequently, as we have already said, as the brake fluid specification alters very little after its first few months of use, it no longer has to be systematically changed. However, if extensive work is carried out on the braking system, such as replacing a caliper or a wheel cylinder or, obvioulsy, a complete overhaul, all the fluid in the system is to be replaced."
to change the brake fluid or not to change? - bathtub tom
>>dates from circa 1988

Things can change in twenty years!
to change the brake fluid or not to change? - George Porge
Things can change in twenty years!


What like ABS, ever better machining processes, heavier cars, more power..........

Has anyone got a handbook for a modern Reno? Any mention of sealed for life brake fluid?
to change the brake fluid or not to change? - Click4
OEM manufacturers that the brake fluid in their vehicles lasts the life of the vehicle .. ...GM, Ford and Chrysler have no recommendation for brake fluid service based on moisture because it's not considered a safety threat or service issue. ... "

I know this is an old thead.

But the above is not 100% true,

http://www.etis.ford.com

get the service schedule, and at the bottom it says,

Extended Period Maintenance Brake system Every 2 years - Renew - brake fluid (LTS 12 154 4)



to change the brake fluid or not to change? - Cyd
Boiling brake fluid is a myth.

No it isn't. Although it isn't usually the brake fluid itself that boils, but the water content causing a vapour lock in the fluid line

I know this from years of rally driving and building rally cars. Also 24 years as an R&D Engineer in Automotive Engineering.

There is also reference to this phenomenon in the Hydraulic Fluids section of the Bosch Automotive Handbook.

Although it is possible for brake fluid to boil. Old style 2 pot calipers were prone due to there being a fluid bridge between the two halves of the caliper. Happened to me once on a night rally.

to change the brake fluid or not to change? - JH
Carnie,
and change the coolant every two years too. I alternate them in an attempt to keep the cost down.
JH
to change the brake fluid or not to change? - quizman
You do NOT have to change the coolant every 2 years on many cars. Certainly not on Ford, VW or John Deere tractors.

to change the brake fluid or not to change? - JH
Quizman
I don't have a VW tractor. Sorry! OK, what's the current thinking then? I'm ready to learn, especially if it saves £s.
JH
to change the brake fluid or not to change? - George Porge
Never, ever service your car, save £0000s OK?
to change the brake fluid or not to change? - LondonBus
The comment above re testing is helpful.


Our VW polo had its brake fluid tested last Feb - I asked for a fluid change. Their advice was "fluid ok this time, but change at next service".


When it comes to the brakes on my car, I'm very cautious. The consequences of brake failure don't bear thinking about.
to change the brake fluid or not to change? - ole cruiser
I'm finding this thread a bit of a puzzle. On the one hand, I drove cars in the past for many years without even thinking about the brake fluid except when changing pads. On the other hand, whatever Ford and others may say in the US, my Mondeo handbook is absolutely clear that a 2-yearly change is required. So too on our Picanto (which was reported as "amber" on its first annual service). I find it a bit hard to believe that such a consistent set of recommendations is just drummed up by the distributors in the UK to support the dealers. So what's it all about? Perhaps as some have suggested the "sponginess" associated with water creeps up on one without really being noticed. Or is it the ABS point which is the killer? Anyhow, if it is blackmail, it is effective as far as I am concerned: they get changed at 2 years.
to change the brake fluid or not to change? - Pugugly
ABS I was told (on this very website)
to change the brake fluid or not to change? - daveyjp
ABS I was told - by our Toyota dealer on Friday when the Aygo was in for a service. A few quid every two years for a fluid change or a new ABS pump? I prefer preventative maintenance.
to change the brake fluid or not to change? - Mchenry
Whenever I undo the bleed nipples to lose a bit of fluid to push the pistons back when changing the pads, the fluid comes out as clean as the stuff in the reservoir. I've never found any 'dirty' fluid.
Can someone tell me how the 'dirty' fluid in the caliper gets back into the ABS pump? If there's any movement, fluid only ever goes one way, certainly not from the wheel back to the ABS under the bonnet
to change the brake fluid or not to change? - Number_Cruncher
>>Can someone tell me

Diffusion
to change the brake fluid or not to change? - nortones2
Thermal syphon?
to change the brake fluid or not to change? - George Porge
One of the front wheels (the ones that do most of the braking and hit the puddles first) is only around 2 feet from the ABS pump on most cars, 10 year old unchanged fluid thats been stirred on every application of the brake pedal, gets shoved back up to the pump when the brake pads are changed when the pistons are pushed back (bad practice I now, but it still happens rather than the prefered method of opening the bleed nipple).



to change the brake fluid or not to change? - gordonbennet
I've pulled enough slave and master cylinders apart over the years to replace seals etc, and seen the evidence of gunge, and rusty coloured moisture laden fluid to convince me that regular fluid changes are worth the very reasonable cost involved.

Whether fleet managers think it worth it or not doesn't mean a great deal, i used to work for a large company in the 80's who ran VW/Audi diesel company cars, they had a policy of not replacing cambelts, strangely enough the rest of the in house servicing was good, quite bizarre.
Presumably the many thousands of pounds involved in the gradual replacement of most of the engines on the fleet made some sort of economic sense to someone.

And by the way, i have had total brake failure though not through heavy braking...i borrowed my sisters Wartburg Knight many years ago and after travelling down the motorway for some 50 miles without braking, when i applied the brakes on the slip road, foot to floor..nothing, luckily the handbrake was very good, i changed the fluid for good quality stuff and the problem never recurred, i had put it down to cheap rubbish fluid, but still unsure.
to change the brake fluid or not to change? - quizman
Oh come on, the handbrake will not stop a car very quickly.
to change the brake fluid or not to change? - gordonbennet
Oh come on the handbrake will not stop a car very quickly.


Just as well it did though, as descending the A1M South slip road for the Welwyn turn off, thats the only thing that pulled the car up, being 2 stroke the engine braking was all but zero and having freewheel (do you know i can't remember if that was switchable, or indeed if sisters car had it, but i'm sure it did) didn't help with that anyway.

They were big drums on the rear of the Wartburg, unlike more modern cars often with rear disc brakes and tiny handbrake shoes inside the inner drum.
I certainly wouldn't want to stop my ageing MB on the parking brake, several hundred yards later would be the likely result.

You've made me think here QM, and i fully understand your disbelief, many of my older generation cars had superb handbakes easily capable of locking the rear wheels at quite high speeds, is there a modern car that could do the same?

The thought of similar failure with an electric handbraked car makes me shudder, not as i'm ever going to find out.
to change the brake fluid or not to change? - edlithgow
>> being 2 stroke the engine braking was all but zero and having freewheel (do you know i can't remember if that was switchable, or indeed if sisters car had it, but i'm sure it did) didn't help with that anyway.



Probably not switchable. I've driven a four-stroke SAAB99 that had a switchable freewheel but my understanding was that the freewheel, though retained as a fuel economy measure, was originally included in the two-stroke cars to protect them from siezure during engine braking, when the engine would be relatively un-lubricated on a premix 2-stroke.



If thats correct, it'd defeat the object to make it switchable.



Apologies if this is obvious, and for going off the 'tis/tisn't topic, but perhaps its a bit of a break from brakes.



The SAAB owner was scared of the freewheel and never used it. (I coast a lot anyway so I loved it). Didn't want to sell the car but, I heard later, scrapped it when the handbrake failed.



Terrible waste of machinery.

Edited by edlithgow on 15/01/2014 at 03:20

to change the brake fluid or not to change? - jc2

Saab freewheel was still around when they fitted the Ford V4 and that was a four-stroke.

to change the brake fluid or not to change? - jbif
Dox, as you probably know, the USA is one of the most litigious societies on this planet.

Bear that in mind when you read that: GM, Ford and Chrysler
" .. have no recommendation for brake fluid service based on moisture because it's not considered a safety threat or service issue. "
" the brake fluid in their vehicles lasts the life of the vehicle ".

Technology has moved on from the sixties and seventies, except for those who are stuck in a British Leyland mentality, and still play records on a gramaphone.

Same applies to long-life oil. You may be changing your 20w50 dead-dinosaur derived oil every 3000 miles while the new world changes 0w30 synthetic oil every 20,000 miles.

What's an iPod and iTunes, did I hear someone ask?

Edited by jbif on 25/01/2009 at 15:16

to change the brake fluid or not to change? - George Porge
We've got a wind up gramophone, record deck, CD player, Ipod...........All have their merits.

Change your synthetic you say? Surelly its sealed for life like gearboxes in the good old US of A. Glad you mentioned America, they're going cap in had to their government for handouts because they've been so far up their own backsides they've been producing dinosaurs for years and now no one wants to buy them :oO

They ignore the rest of the worlds car manufacturers recommendations for because they know best and wonder why there engines are full of sludge.


to change the brake fluid or not to change? - Number_Cruncher
>>It's the moisture in the (hygroscopic) moisture absorbing brake fluid that causes the damage.

I don't think that's true.

I did think exactly that - it's the standard view - but, I'm not sure anymore.

I have known about the problem of metal ions in the brake fluid for some time, but, I didn't think it was the over-riding concern. I'm prepared to be convinced either way, but I would need to see something a bit more scientific, preferably published in a peer reviewed journal.
to change the brake fluid or not to change? - madf
Anyone who has tried to bleed long neglected braking systems will know:
1, The bleed valves are probably rusted closed
2. The flats on the valves have corroded so you need to use mole grips.
3 The bleed screws will snap off if not treated carefully.
4. The barkle fluid inside the calipers/wheel cylinders is full of muck.

So whether or not a fluid change is needed or not, an inspection and bleed every 2-3 years in the long run keeps the car safer.

Of course if you only buy new cars and keep for 3 years, none of the above is relevant.


And in my experiience, the Japanese designed braking systems have much sturdier bleed screws than European ones.



Since the US car industry stopped leading car technology roughly after the invention of the automatic transmission, I ignore everything they do. The industry there is roughly 25 years out of date technologically and 100 years in outlook,

(The story of the introduction of disk brakes to US muscle cars is worth reading. 450hp claimed and front drum brakes... )
to change the brake fluid or not to change? - captain chaos
Since the US car industry stopped leading car technology roughly after the invention of the
automatic transmission I ignore everything they do. The industry there is roughly 25 years out
of date technologically and 100 years in outlook
(The story of the introduction of disk brakes to US muscle cars is worth reading.
450hp claimed and front drum brakes... )

>>
Aye, they were meant to go, not stop ;-)
As for stopping leading car technology, your airbags, side impact bars, air con, power windows/seats, locks, remote mirrors, and much more were all US innovations.
In 1971 you could still buy a Morris Minor or Morris Oxford....nothing available this side of the pond with 450 brake though... ;-)
to change the brake fluid or not to change? - nortones2
"I did think exactly that - it's the standard view - but, I'm not sure anymore."

Why is it that you are not sure anymore NC?


Edited by Pugugly on 25/01/2009 at 19:36

to change the brake fluid or not to change? - captain chaos
They ignore the rest of the worlds car manufacturers recommendations for because they know best
and wonder why there engines are full of sludge.

Can't see how, seeing as most Americans change their oil and filter every 3000 miles. They ran 15-30 oil for donkeys years too as they had hydraulic tappets (introduced by Cadillac in the fifties IIRC). Britain caught up 30 years later with the Cavalier ;-)
to change the brake fluid or not to change? - Cyd

ABS makes it more imperative to change the fluid regularly. The increased compressibility of brake fluid with 2% or more moisture content seriously affects ABS performance.

to change the brake fluid or not to change? - Manatee
I don't see why normal braking performance should deteriorate as the water content of the fluid increases, and I'm pretty sure it doesn't.

The boiling point will reduce, though brake fluid can boil when new if it gets hot enough. As long as it doesn't boil then water is just as incompressible as brake fluid so why would it make any difference?

The risk of corrosion is alleged to increase and I don't recall fluid changes being part of a service regime until the ABS era.

I wouldn't give much credence to the muck-in-the-lines risk, changing the fluid is as likely to move it to the ABS pump as eliminate it.

I do get mine changed, but it would not worry me if it was a year or two over. The only experience I know of (my brother's) re boiling fluid involved fluid that was almost certainly 12 years old and the car was driven and braked very hard indeed. The pedal went to the floor, no perceptible retardation.
to change the brake fluid or not to change? - nortones2
I think the issue is that water content changes phase, at a lower temperature than brake fluid. Thus, with say 5% water content, and severe brake use, the master cylinder is trying to move a compressible gas, and the fluid. Result: brake pedal travel increases. Eventually compensation is impossible, and the brakes are US. You might like to see this www.aa1car.com/library/bfluid.htm A strong argument, as far as I can judge, that water content is not a good thing for brake fluid. Ford USA seem to have shifted ground also, according to that piece.
to change the brake fluid or not to change? - Number_Cruncher
>>Why is it that you are not sure anymore NC?

First, I must clarify, I'm not one of these who argue with the idea of changing brake fluid per se - it gets changed annually in our cars.

However, I've never seen any research which really gets to the bottom of this. I'm not particularly satisfied in how the boiling point criteria are justified, and I haven't seen how limits might sensibly be applied to copper ion concentrations. I haven't seen anything thst definitively decides which mechanism is the most important.

I'm sure water in the brake fluid isn't a good thing, but, is it the over-riding concern when there are other mechanisms at work?

While we've all seen the results of corrosion on braking system parts, how many of us can be sure that the corrosion is the result of water, or the result of other chemical action.

I've been guilty of not questioning what I've been told about brake fluid, and not seeking out the original research. I suspect I'm not the only guilty one, and I have lazily trotted out received wisdom in similar previous threads without question.

to change the brake fluid or not to change? - nortones2
OK NC: fair enough but given that contamination is a real factor, I only change fluid at the mfrs recommended intervals. Reduces the risk of foul-ups, if indeed the fluid is changed at all! In the reference above, the web-site also looks at an NHTSA "survey" which is said to have found "the brake fluid in 20% of 1,720 vehicles sampled contained 5% or more water" Water and steel = rust. Probably because for water to gain ingress to the system, oxygen will also. Some of the components (flexible hoses) are likely to be subject to minor permeability. Nothing is perfect:)
to change the brake fluid or not to change? - gmac
I changed the brake fluid on our motorbike last summer after 10,5 years.
Up until that point the brakes felt fine however, after the change the brakes felt (in my unscientific hands) 100% better. That was after 10,5 years.

Our Volvo went in for its 4 year service last November, they changed the fluid without asking. Result: Much improved brake feel and stopping. Only cost ?40 so I'm not really going to argue the toss.
to change the brake fluid or not to change? - Timelord
I can only say that the brake fluid on my Golf was changed at 4 years, and it noticable improved the feel on the pedal
to change the brake fluid or not to change? - madf
Agree with Cliff Pope.

Change all fuilds regularly except I use OAT longlife antifreeze - 10 year life..
And I ignore power steering fluid.
A gearbox oil change improves longevity - and on some autos is essential (Audi A8?Mercedes) even when not on the schedule as owners found to their cost.

If you do not change brake fluid on a Mark1 Lexus GS300, you will likely need a new combined mastercylinder/ABS system £1600 new.. PLUS fitting. -after 100k miles

Save a mickle, waste a muckle..

(the motto of the MOD who omitted some radar systems on new helicopters so only flyable in good weather..)

Edited by madf on 26/01/2009 at 13:47

to change the brake fluid or not to change? - Number_Cruncher
I agree with Cliff, except for this bit;

>>You don't have know the full scientific reason for the deteriortion

For those who test their brake fluid to determine when to change the fluid, testing for the right type of contamination is important. It might be that testing for water content is a bit of a red herring, and we all should have been looking at the concentration of metal ions.

to change the brake fluid or not to change? - George Porge
To all you nay sayers;

If legislation was bought in where a vehicle (we could be talking of a heavilly laiden large van and not a Micra) had to be serviced exactly to the maufacturers schedule or you personally had to sign a disclaimer to ommit a BFC. If it could be proven the BFC could have prevented a fatallity you would be charged with manslaughter and have the oppertunity of a long stay sharing a cell with Big Bob on wing G would you be as brave as you state and sign?
to change the brake fluid or not to change? - quizman
If water gets into the brake fluid and then boils, why doesn't it just boil away?

I have my brake fluid changed when I have new pads.

Why are there not dozens of wrecked cars at the bottom of steep hills?
to change the brake fluid or not to change? - bathtub tom
>>If water gets into the brake fluid and then boils, why doesn't it just boil away?

It boils locally, at the source of the heat, the brake caliper. The only vent in the system is at the reservoir cap. An awful lot of the system would need to boil for it to vent off and as the brakes are presumably applied to make it boil, the master cylinder would block that path.
to change the brake fluid or not to change? - Altea Ego
Dox

There is

a: no such legislation
b: BFC is not on the manufacturers "schedule" its merely a recomendation. If it were so the garage where you have your car serviced would do it without asking. Most of them dont.

If it were so "safety critical" as you suggest would they not be prosecuted for negligence. Certainly after the fatal accident caused by brake failure on your three year old brake fluid.

Except three year old brake fluid is not a cause of acccidents, or 4 or 5....

Edited by Altea Ego on 26/01/2009 at 16:49

to change the brake fluid or not to change? - George Porge
AE, sign or not?

10 year old brake fluid in a LWB hitop 3 - 500K mile transit loaded to excess, gets your stamp of approval?

Get off the fence an fill in some detail, state that brake fluid should never, ever be changed if thats your view

to change the brake fluid or not to change? - Altea Ego
AE sign or not?
10 year old brake fluid in a LWB hitop 3 - 500K mile transit loaded
to excess gets your stamp of approval?
Get off the fence an fill in some detail state that brake fluid should never
ever be changed if thats your view


Now your getting tired and emotional Dox. your 500k 10 year old transit would have had new seals by now and as you know the fluid would have been changed when that was done.

Dont go to unrealistic extremes to try and prove your point dear boy.
to change the brake fluid or not to change? - George Porge
No details again.

Seals? :o/

A parcel courier can easilly rack up 75K P.A (1500 per week / 300 per day) for the first 4 years of a vans life, sold on to a tradesman and after 10 years the odo could easilly read 300 - 500K.

I've already proved my point, the fact that you don't provide any answers, only vague opinion.

>>>>Now your getting tired and emotional>>>

>>>Dont go to unrealistic extremes to try and prove your point dear boy>>>>

Others can make their minds up about your comments in your last post

:o)
to change the brake fluid or not to change? - Altea Ego
dox, you know a 10 year old, 500k miler would have had major brake work and the fluid changed while that was being done.

Here is some facts for you dox

I have driven over 500,000 miles, for 37 years, never changed the brake fluid as a routine service item and never had brake failure becuase of it.


to change the brake fluid or not to change? - George Porge
I have driven over 500 000 miles for 37 years never changed the brake fluid
as a routine service item and never had brake failure becuase of it.


Selective with your statements again, 37 years in how many motors?

When the brake fluid get degraded instead of a BFC you change the car ;oO

Question for AE, after an application of the brakes, what pulls the pads off the disks and gives clearace to prevent brake drag and eventual overheating of the pads?

Edited by Dox on 27/01/2009 at 16:18

to change the brake fluid or not to change? - Altea Ego
Question for AE after an application of the brakes what pulls the pads off the
disks and gives clearace to prevent brake drag and eventual overheating of the pads?


Nothing - the run out of the disks pushes them away
to change the brake fluid or not to change? - 659FBE
Not quite right. The piston seals are designed to yield slightly such that for normal brake application, they generally move within their elastic limit. It is this elasticity which returns the pads to the released position. Other factors such as wheel bearing runout will have an influence, but a modern hub with pre-loaded angular contact ball bearings should have almost zero play.

The seals only move on the pistons when the lining wear becomes such that the seals' elastic limit is exceeded - or, of course, during installation when the pistons are moved by large amounts.

659.
to change the brake fluid or not to change? - Altea Ego
Not quite right. The piston seals are designed to yield slightly such that for normal
brake application they generally move within their elastic limit. It is this elasticity which returns
the pads to the released position.


But as the pistons are not actually fixed to pads, the elasticity in the seals only pulls back the pistons not the pads.
to change the brake fluid or not to change? - mjm
It's rather like long life coolant, isn't it?
Can anyone guarantee that a hose/radiator, whatever won't let go in that time?
I also thought that the boiling point of water increased with an increase in pressure. So the likelyhood is that the brake fluid flash boils when the pressure is released, ie brakes released.

In my opinion brake fade is far more likely to affect stopping than old brake fluid.
to change the brake fluid or not to change? - oilrag
No one has mentioned the possible risks of changing brake fluid frequently.
The careless main dealer apprentice getting grit into the system by popping the reservoir cap on the under bonnet surface, face down.
Or the place that uses the cheapest fluid possible with a wiped out funnel.

Iv`e actually seen the latter, at a city ring road tyre and servicing place (uncapped low DOT never heard of brand container fetched from back of workshop) and the former (and worse) many years ago when working briefly in the workshop of a main dealer - before going to university.

Those little rubber (non captive) caps on the wheel cylinder bleed valves - they were always missing after a fluid change.
Gearbox plugs were just tossed onto the ramps too - threads rolling in the grit just transfered there by the tyres.

I`m starting to sound negative - Sorry ;-)
to change the brake fluid or not to change? - quizman
I agree with you oilrag, I've seen filthy oil jugs being used at garages with all sorts of muck going into your vehicle. That is why I like to do oil changes myself, but the trouble is I don't feel confident to do a brake fluid change.
Is it easy to change the fluid yourself, or will the bleed nipples break off, or will air get in, or will I get in a right old mess?
to change the brake fluid or not to change? - madf
DIY brake fluid change is easy with axle stands . A hands free bleeding kit (check they fit the neck of your master cylinder) is very useful.
But mine does not fit the Yaris so I do it manually using a long stick twixt clutch and seat to hold down pedal down when closing off the valves. I also use a one way valve in the rubber attached to the bleed screws.

A bit of penetrating oil round the bleed screws and care means the last one I broke was on a 1968 Mini (they rust badly)..

A job for a clean dry garage on a warmish day.
to change the brake fluid or not to change? - George Porge
tinyurl.com/2qxjcn

tinyurl.com/aoz3nm

A couple of links worthy of a peruse
We took a capri RS3100 round castle combe. New brake fluid? nope at least 4
years old. The brakes failed.
reason? the pads got so hot they glazed then broke up then fell out. The
brakes were so hot they couldnt be worked on for two hours. Brake fluid boiled?
nope.


Now given the above links and pad / fluid temps stated and your stated 2 hour rest period before the brakes could be worked on are you still implying the fluid never boiled in the Capri?

I'll let other backroomers make up their own minds.

My last post on the subject ;o)
to change the brake fluid or not to change? - Altea Ego
Now given the above links and pad / fluid temps stated and your stated 2 hour rest period before the brakes could be worked on are you still implying the fluid never boiled in the Capri?

Yes

Next?
to change the brake fluid or not to change? - madf
Since the brakes were inoperable, how the poster knew the fluid had not boiled is beyond me.

Of course, if he's sitting waiting for steam from the master cylinder then rofl
to change the brake fluid or not to change? - Altea Ego
Since the brakes were inoperable how the poster knew the fluid had not boiled is
beyond me.


Because i was driving it and you were not. The brakes were fine before the pad material broke up and fell off. you can kind of tell, one minute they work and the next they still work but very noisily.
Of course if he's sitting waiting for steam from the master cylinder then rofl


ROFL

(not)
to change the brake fluid or not to change? - motorprop
Just got my 04 Nissan X trail 2.5 auto back from the annual service / MOT, my first major service for it : I read the manufacturer's handbook and for a ' level 3 ' service they recommend changing the brake fluid, so added that to the list given to the garage . Collected the car today and when settling the bill, the garage owner said that ' normally ' a brake fluid change is ' £70 - £80 ' , although I paid a bit less, not sure exactly how much as it was a compounded total price .

How long will it take 2 mechanics to do ( they have 2 mechanics plus the boss , it's a small indie in an industrial area of West London ) ??

I mainly went for the fluid work as it's a part of the recommendations and partly down to the comments I read on this thread.


the total bill for a full service ( but without oil / filter as I had them done elsewhere a month ago ) and MOT was £265, which isn't too bad,

Edited by motorprop on 28/01/2009 at 16:07

to change the brake fluid or not to change? - harib
Mycar (Seat Leon) is about 2 weeks away from its 2 year service. Looking through the details in the service book, it says that the brake fluid must be changed every 2 years. I assume that this is a VAG thing rather than just a Seat thing. So if I refused to have it done, would it invalidate the warranty?
to change the brake fluid or not to change? - Dynamic Dave
A lot of manufacturers recommend 2 yr changes, not just VW.
to change the brake fluid or not to change? - quizman
VW say that the fluid should be changed after 3 years on a new car and then every 2 years.
It says this in my Golf handbook, so it is correct!
to change the brake fluid or not to change? - Armitage Shanks {p}

Correct for a Golf of that age. There are different brake fluids in current use and some of them are less hygroscopic than others. My garage checks the moisture content of the fluid by measuring the boiling point of a sample; this gives a measure of the %age of moisture in the fluid.

to change the brake fluid or not to change? - Big John

I once had brake failure due to moisture in brake fluid.

I also remember changing the brake fluid on my dads Volvo 740 many years ago. What I though was a dark coloured brake master cylinder resevoir suddenly changed colour to a light straw. It also then flagged a fault light showing dual circuit problem which turned out eventually to be a rusted up sensor due to the water content of the brake fluid!

I now ALWAYS change brake fluid every two years. I've just had a service and was only charged £15 extra for this...

to change the brake fluid or not to change? - Bromptonaut

Somebody on same holiday capsite as us 10 yrs ago had brakes on their Astra fail coming down the Alp dHuez road. Faded to nothin v quickly. Fluid change would have prevented but less physical brake and more 'frein moteur' would have averted.

Follw people down thse sort of roads and their brake lights are on near contiuously. MEanwhile I've got a lowish gear, no roght foot (or lightly on less steep bits) and just dab brake to slough off any excess.

to change the brake fluid or not to change? - Dutchie

Why refusing to have the brake fluid changed warranty or not.The stuff absort water and for peace of mind change it.

to change the brake fluid or not to change? - Cyd

Actually, I've come to the conclusion that this thread is quite distressing.

It's scary to think that one day my life and that of my kids could be dependant upon the defective brakes of someone who thinks changing brake fluid is some dealer conspiracy!!

to change the brake fluid or not to change? - madf

I read threads like this infrequently as people who think they know better than car makers how to maintain cars tend to be rather fixated on the subject.

I prefer to be dumb and service as per manufactiuirer's recommendations.

to change the brake fluid or not to change? - John F

I read threads like this infrequently as people who think they know better than car makers how to maintain cars tend to be rather fixated on the subject.

The beauty of such forum debate is that many contributors probably DO know and understand more about physics/hydraulics etc than 'car-makers'. It is always wise to question dogma to check it still holds good.

I have driven over 40yrs in mainly old cars and I have never routinely changed brake fluid. I occasionally push out a few mls from the bleed valve when changing pads.

The only time I have seen dirty fluid was when I finally had to replace the rear brakes on my 1980 TR7...a couple of years ago. Its front calipers are still original.

I have never, ever, taken my cars to a garage for a 'service'......apart from the one time in my life I bought a new car [early eighties] as occasional oil/filter change is all they need nowadays. The MoT provides the security that they remain safe.

to change the brake fluid or not to change? - madf

"I have never, ever, taken my cars to a garage for a 'service'......apart from the one time in my life I bought a new car [early eighties] as occasional oil/filter change is all they need nowadays. The MoT provides the security that they remain safe."

Thank you for providing the assurance that your post is worth ignoring.

Anyone who relies on the MOT system is seriously deluded.

to change the brake fluid or not to change? - Avant

I wouldn't go as far as that, madf: the MoT has never been an absolute guarantee of anything, and isn't meant to be. But a certificate from a reputable garage surely provides a level of assurance of roadworthiness?

to change the brake fluid or not to change? - madf

I wouldn't go as far as that, madf: the MoT has never been an absolute guarantee of anything, and isn't meant to be. But a certificate from a reputable garage surely provides a level of assurance of roadworthiness?

Yes for that moment in time.

But it relies of the motorist then being competent enough to ensure all the significant Advisories are dealt with before they become saftye threats.

eg brake pads so far down they will last 1,000 miles, tyres at 2mm tread etc.

What of course it does not do is pick up the signs of incipient engine failure due to neglect - oil fiilter not changed - air filter , thermostat on the way out, radiator worn out - which can lead to sudden and expensive engine failure...

The OP posted you drove older cars : the supply of these less complex vehicles is slowly diminsihing.. Complex electronics need some maintence such as insuring no water ingress to vulnerable boxed containing ecus etc.. See floor mounted ECUs as loved by VW/Auid.

(I am not saying garages will do any better but a competent and conscientious garage should)

to change the brake fluid or not to change? - MG763

I have recently bought a Volvo s40. The car is two years old this week and so I booked it in to Volvo for a service. Previously with my Ford Focus I always used my local garage which I have to be honest with I trusted. However I thought new car, should really get it serviced by Volvo. Well the service will cost me £290 which I think is expensive (its being done as I type this) however they have now phoned to say its a recomendation to change the brake fluid every two years and that will be another £90 (not sure if that includes VAT). The car has only done 14,500 miles. I do understand the debate about safety but have a couple of points.

Firstly is that a fair amount to charge me ?

Second if it is so vital and a safety issue why is it not part of the standard service ?

welcome your thoughts

to change the brake fluid or not to change? - skidpan

Changing brake fluid is pretty much essential. Brake fluid absorbs moisture form the atmoshere which reduces its effctiveness, the water also can corrode internal components.

Some manufacturers recoment 2 years, some 3, doing a lowish mileage 3 would be fine (its what I do averaging 7500 miles a year) but not doing it as per the manufacturers schedule wilst the car is under warranty could affect a claim if there was a brake componnet failure.

£90 is very expensive, never paid more than £40 or £50 even at BMW main dealer.

Most garages give you a cheap(ish) quote for the service and then ring up adding extras as they inspect the car. Ford are the perfect example of this. The Kia garage we use give a price for ALL that is needed, no extras but garages like that are rare. I have a service plan on my new Seat, it needs a brake fluid change at 2 years, its not included in the plan because they state it is a maintenance item and not a service item. I knew this when I took the plan out thus not surprised. Its is £49 extra for the fluid change.

to change the brake fluid or not to change? - bathtub tom

I'm an advocate of refreshing brake fluid, but I think garages are having a laugh for charging what they do when testing kit is cheaply available: www.ebay.co.uk/sch/i.html?_nkw=brake+fluid+tester&...5

You can test it yourself (jump to 1:40 for the relevant bit) workshop.search-autoparts.com/_Can-You-Believe-Thi...l

to change the brake fluid or not to change? - John F

Some manufacturers recoment 2 years, some 3, doing a lowish mileage 3 would be fine

This is caution to the point of absurdity. Have you never pondered upon the concept of 'conflict of interest' of those who make a living out of making and servicing cars when they write and publish their recommendations?

It was good to revisit this thread; interesting to see how some manufacturers used to be honest enough to publish advice which inferred that brake fluid, like coolant, would probably last the life of the car.

Croatia looks as though they have got it right, if the poster who mentioned their MoT requirement is correct.

to change the brake fluid or not to change? - Armitage Shanks {p}

Brake fluid can and does absorb moisture from the atmosphere. This just might cause damage to a very expensive part of the braking system ie the ABS pump. The test is cheap and simple and if it indicates that a fluid change is recommended it would be foolish not to do so.

to change the brake fluid or not to change? - skidpan

This is caution to the point of absurdity. Have you never pondered upon the concept of 'conflict of interest' of those who make a living out of making and servicing cars when they write and publish their recommendations?

A brake fluid change costs under £50 at a garage, £15 if I DIY. In 3 years over approx 25,000 miles I use over £3300 worth of petrol. I aslo spent £90 on RFL, £700 on insurance and £500 in servicing, total £4140.

At £50 brake fluid change adds 1.2% to my motoring costs, hardly a 'conflict of interest' is it to keep me and other road users safe and ensure my car is in top condition.

I have said it before please don't keep advising peoople to do as you do when it is against all common sense and advice.

to change the brake fluid or not to change? - John F

I have said it before please don't keep advising peoople to do as you do when it is against all common sense and advice.

You can repeat it as often as you like, skidpan, but I am as entitled as you are to proffer advice. It has served me well over the past 45 years of car ownership. Goodness knows how much I would have spent if I had taken our cars to a garage every year for a 'service' ! Like it or not, I choose not to pay someone £100 per hour to oil the door hinges and inspect what few moving parts are inspectable these days.

There is also arguably no such thing as 'common sense' . The phrase is often used by those whose credentials and arguments carry little weight. If you would like to know a bit more about its shortcomings, try googling 'Stanley Milgram experiment'.

In matters of scientific debate I would advise taking heed of those who have both advanced qualifications and experience of the subject under discussion. Unfortunately there is little evidence of their presence on these threads, because they presumably, and understandably, can't be bothered.

Can anyone explain how the 'exposure to [water in the] atmosphere' takes place in a sealed braking system?

to change the brake fluid or not to change? - Bromptonaut


Can anyone explain how the 'exposure to [water in the] atmosphere' takes place in a sealed braking system?

Err the system is not wholly sealed is it?

Air has to get in and out as the fluid level varies with use/wear. For that reason there's a breather hole in the reservoir cap. Traces of water may also bypass joints in piping or seals.

to change the brake fluid or not to change? - Bromptonaut

This is caution to the point of absurdity. Have you never pondered upon the concept of 'conflict of interest' of those who make a living out of making and servicing cars when they write and publish their recommendations?

It was good to revisit this thread; interesting to see how some manufacturers used to be honest enough to publish advice which inferred that brake fluid, like coolant, would probably last the life of the car.

Croatia looks as though they have got it right, if the poster who mentioned their MoT requirement is correct.

John,

While I agree with you that oil changes might be undertaken at longer than 12mth intervals in some usages brake fluid is another matter.

The risk is that it absorbs moisture. That is likely to be a consistent process irrespective of mileage or usage pattern. The first time you know there's a problem is when your brakes fade/fail on a long descent. Happened to some folks we met on holiday a few years ago going down from Alpe D'Huez.

IIRC there are two types of brake fluid in use either Glycol or Silicone based. They're not mixable. Silicone based fluid is not hygroscopic but there appear to have been other issues with it in ABS systems. While it might have lasted life of car I don't think any glycol based fluid comes with such a guarantee.

Coolant degrades over time too. As well as its antifreeze properties it inhibits corrosion, particularly in engines with alloy componenets.

to change the brake fluid or not to change? - jc2

Silicon based fluid is just as bad if not worse-instead of water being absorbed into the fluid,it forms globules in it.

to change the brake fluid or not to change? - Wackyracer

I can't think of any good reason not to change brake fluid, I know on cars with steel bodied calipers or wheel cylinders they would rust inside and damage the seals if the fluid was not changed for many years.

to change the brake fluid or not to change? - John F

The risk is that it absorbs moisture.

I agree, but I doubt if it absorbs much. And according to Wikipaedia DOT 5 when 'wet' has almost the same boiling point as pristine dry DOT 2. So unless you are driving enthusiastically up and down Alps it is unlikely to be a problem. As a previous poster has mentioned, do not confuse fade with pockets of gas/steam.

My records show that I eventually changed the fluid in my 1980 TR7 in 1989. It eventually sprang a leak in the o/s rear cylinder in 2000 so I cleaned it and replaced the rubber piston seal. I had to replace the seal again in 2004. Finally, in 2010 it got a pair of new rear cylinders. The fronts [disc calipers] are still original, although the pads are tiny and need replacement every 12,000m or so.

to change the brake fluid or not to change? - Andrew-T

< IIRC there are two types of brake fluid in use either Glycol or Silicone based. They're not mixable. Silicone based fluid is not hygroscopic but there appear to have been other issues with it in ABS systems. >

Since the scientists are bantering here, I'll add my 2p-worth. I am not up-to-date with brake-fluid technology, but until the arrival of the silicone variety, I believe the usual fluid was a high-boiling ester such as dioctyl phthalate; glycol is fully miscible with water and much more hygroscopic. That is why glycol is the standard basic antifreeze.

Even though phthalates don't mix with water, normal use of a braking system heats the fluid in the calipers, and the master cylinder in the engine compartment will also get warm. Both effects require a breather in the system, leading to gradual ingress of moist air and condensation [though not if the car sits idle, presumably]. When this percolates over time to the brake cylinders the moisture could boil and cause some loss of braking.

The recommended 3-yearly change of fluid probably includes a generous safety margin, and if the brakes are never extended some accumulation of moisture will probably have no noticeable effect. Skidpan may change his fluid every year, and John F not at all - probably neither will suffer, and both will feel justified.

to change the brake fluid or not to change? - Avant

Andrew T and RT - I do apologise for deleting your posts, but they were in (justified) response to Skidpan. I have no alternative but to delete his posts evey time he gets personal.

to change the brake fluid or not to change? - Andrew-T

Avant - boy, you're quick on the draw today!

to change the brake fluid or not to change? - skidpan

Andrew T and RT - I do apologise for deleting your posts, but they were in (justified) response to Skidpan. I have no alternative but to delete his posts evey time he gets personal.

Whio is having a laugh now. My post deleted by Avant was not personal. It simply pointed out the Andrew T had no justification to say "Skidpan may change his fluid every year", since I never said that. To repeat what isaid in a post on Tuesday "I change my brake fluid every 3 years after the warranty conditions end".

Andrew T was obviously trying to bait me and now the moderator has joined in.

to change the brake fluid or not to change? - RT

Andrew T and RT - I do apologise for deleting your posts, but they were in (justified) response to Skidpan. I have no alternative but to delete his posts evey time he gets personal.

Whio is having a laugh now. My post deleted by Avant was not personal. It simply pointed out the Andrew T had no justification to say "Skidpan may change his fluid every year", since I never said that. To repeat what isaid in a post on Tuesday "I change my brake fluid every 3 years after the warranty conditions end".

Andrew T was obviously trying to bait me and now the moderator has joined in.

My post was intended to be supportive of Skidpan - it was Andrew-T's personal reference to him that started the personal bit.

I think Skidpan's comment here seems justified.

to change the brake fluid or not to change? - skidpan

I think Skidpan's comment here seems justified.

Thank you.

to change the brake fluid or not to change? - Andrew-T

< Andrew T was obviously trying to bait me and now the moderator has joined in. >

My lack of comment indicates the pointlessness of continuing this. As Skidpan is now accusing Avant of 'baiting' him, that merely shows how easy that is.

I said nothing more provoking than what Skidpan has highlighted above. It is not a quote, simply a scenario that I envisaged. I am sorry if anyone finds that offensive, because it isn't.

Edited by Andrew-T on 16/01/2014 at 18:38

to change the brake fluid or not to change? - Avant

This was a discussion worth resurrecting, but not if it gets personal. Thread closed.

 

Value my car