Changing brake fluid

By Graham Smith
Carsguide
26 January 2012

Les
Bribie Island, Qld.

It seems to have become a relatively recent change in car servicing schedules to replace the brake fluid every two years. I can't remember ever having had a brake problem with any of my previous cars, quite a few of which were six to eight years old without ever having the fluid replaced, or bled, for that matter. Has the quality of the modern fluid fallen off so badly that this is necessary, or is this just another dealer ploy to increase the new car sales profit?

Brake fluid can become contaminated over time and it's a good practice to replace the fluid regularly to maintain brake performance.

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I support “Quantum of Solace’s” informed comments.The requirement to replace brake fluid is not new. My first recollection of this requirement is the handbook for my early 1970’s Fiat. Most manufacturers used to stipulate every 12 months but more recent advances in the inhibitors in brakefluid mean this can be increased 24 months (Honda say 36 months). Manufacturers also pay greater attention to preventing moisture entry on master cylinder reservoir caps. The practice of replacing brakefluid of master cylinders only by some dealers and repairers is unethical and dishonest. The hydroscopic nature of brake fluid will pull moisture through brake hoses and past caliper piston seals. Drum brake cylinders are more susceptible to moisture entry and corrosion than modern disc brake calipers - another advantage of purchasing a car with 4 wheel discs! Les from Bribie: You will increase the resale value of your vehicle to a knowledgeable buyer if you replace brake fluid as per manufacturers handbook.
Stewart Eldridge of Qld Posted on 04 February 2012 6:59pm
@Quantum, I’m impressed! Totally agree.
deejay51 of Gold Coast Posted on 30 January 2012 11:03am
This service requirement has appeared over the last 15 to 20 years and is good insurance if carried out correctly. I have checked a number of vehicles after this item was required and have yet to find the bleed points had been disturbed. If carried out at all, it has been done by syringing the fluid out of the master cylinder. This may be the manufacturers procedure, but could not really be defined as changing the fluid. To expand on this subject, my previous Employer purchased a Ford Ranger ute about 4 years ago and during the first week all Company drivers reported the brakes did not feel right. The vehicle was returned to the dealer and picked up 4 hours later with the following report. Brakes bled and road tested and brakes bled again. The bleed points had not been touched and the symptoms were the same. Upon bleeding the system myself, it was found that the load equalisation valve was full of air. Needless to say the vehicle never went back to the selling dealer.
grauncher of sydney Posted on 27 January 2012 8:42pm
Brake fluid is hygroscopic, ie it Readily absorbs moisture from the atmosphere. The short term effect is minimal. Long term you get corrosion in the brake master and slave cylinders. If you get significant amounts of watrer it lowers the temperature at which the fluid can boil. If the water vapourises (ie turns to steam) due to high braking temperatures it will cause brake fading or failure. The quality of brake fuid has never been better. Because you got away with it in the past, doesn’t mean you will in the future. Its called preventative maintenance for your safety.
Quantum of Solace of Melbourne Posted on 27 January 2012 8:18pm

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