Nov 7, 2005

Car Tips 7 - Changing of brake fluid

Changing of brake fluid

There are many types of fluids in the car system that requires constant monitoring and attendance. Changing the many fluids in a vehicle is always a change for the better. Dirty engine oil, transmission fluid or anti-freeze are bad news for a car. But what about brake fluid? Many motorists know that this fluid should be topped off, but is it necessary to be changed?

Brake fluid in the typical vehicle can become contaminated in two years or less. This is because the fluid absorbs moisture, which works its way through the hydraulic system. Under heavy braking conditions, such as those encountered in mountainous or hilly driving or when towing a trailer or heavy vehicle, moisture in the overheated fluid vaporizes (boiling point of water is lower than that of brake fluid) and braking efficiency is reduced.

Even under normal driving conditions, this problematic condition can develop if the brake fluid is seriously contaminated. Not only is the fluid vulnerable to vaporizing, it also can freeze.

Brake fluid must maintain a stable viscosity throughout its operating temperature range. If it's too thick or too thin, braking action is impaired. Beyond the vaporization hazard, moisture creates an additional problem for owners of vehicles equipped with anti-lock braking (ABS) systems. Nowadays most cars come with standard ABS safety features. Moisture can corrode and cause rust. Rusted and corroded ABS components are very, very expensive to replace. So isn't it wiser to have prevention rather than cure.

How does a car owner knows when to have the fluid changed? We recommend replacement every two years or 24,000 miles.

To be even more certain, changing of brake fluid should be included with brake pad or shoe replacement, as a preventive measure, a professional brake technician should check the condition of the fluid with an accurate fluid test safety meter, which is inserted into the master cylinder reservoir to record the fluid's boiling point.

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