September 21, 2011

Came across this when trying to decide if I should change my brake fluid on my `02 KR. This was published in `02 so not sure if it is applicable to newer trucks.

Ford Brake Service Recommendations


BRAKE FLUID FLUSHING?

Ford does not recommend brake fluid change intervals here in the U.S.

In Europe, Ford does recommend changing the fluid every two years. Ford in Europe may follow U.S. lead and change their recommendation to reduce maintenance requirements. Auto makers are looking to commonize world standards.

Main reason to flush is moisture contamination (lowers boiling temperature and increases risk of fluid boil). Ford evaluates brakes on 18 mile long hill in Arizona. Engineers ride brakes down the hill. Temperature of DOT 3 fluid must not exceed 284 degrees F (at 3% moisture contamination). In Europe, they use a different hill and test procedure -- so they get different results. Europe requires DOT 4 fluids as a rule (DOT 4 has higher temperature spec, but DOT 4 boiling temperature drops more quickly as a result of moisture contamination than DOT 3). DOT 4 is more hygroscopic than DOT 3.

Ford says flushing brake fluid may increase risk of causing other brake problems (such as getting air or dirt into system). Brake fluid is also not environmentally friendly (creates disposal problem), so shops should not change it unnecessarily.

NOTE: Different DOT 3 fluids absorb moisture at different rates depending on what additives are in fluid.

Ford says need to flush and change fluid varies depending on the area of the country (no moisture problem in Arizona but there is in Florida), and also on the robustness (corrosion resistance) of the parts in the brake system.

Ford`s service life for brake fluid is 10 years, 150,000 miles (has been this for past four or five years). Ford says if there is a reliable way to test fluid and the fluid tests bad, then it should be changed. Otherwise, leave it alone.

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