Brake Fluid Breakdown

New Brake Fluid Standards...

...Have Created A New Way To Increase Regular Vehicle Service

By Kerry Pipes

No standard for when to replace brake fluid has ever existed in the U.S. - until now. Sure, a variety of tools for testing fluid were developed over the years; but without a clear standard for evaluating the condition of fluid and determining when it should be replaced, brake fluid service was pretty much a guessing game.

This past January, the Motorist Assurance Program (MAP) established the first U.S. standard for brake fluid testing and replacement. MAP concluded that as brake fluid corrosion inhibitors break down, copper used in the making of brake line tubing begins to dissolve into the fluid and accumulate. While copper ions pose no immediate threat to system components they can be measured to reliably predict when brake fluid corrosion inhibitors become depleted.

MAP established that when copper concentrations reach 200 parts per million (ppm), brake fluid has lost its capacity to inhibit metal corrosion and should be replaced. Although the fluid will still perform its primary job of stopping the vehicle, it can no longer fight corrosion among internal metal brake system components.

This new guideline brings a new opportunity for service professionals to strengthen their relationships with customers. Every service professional knows the impact extended engine/powertrain warranties have had on business. Regular oil changes, annual winterization, and tune-ups have offered a regular and frequent opportunity for service technicians to inspect customer vehicles for needed service. The new MAP guideline on brake fluid service offers service departments the chance to recover a point of regular vehicle service to replace the once important engine tune-up.


For years the standard by which brake fluid was evaluated was water content. Today, very little water gets in brake systems and water content provides no clear indication of the state of brake fluid's corrosion fighting chemicals.

Today's ABS-enabled vehicles have had problems with stopping distance during panic braking because of corrosion build up on important metal parts and valve surfaces. A vehicle with traces of water in the fluid can still stop, but corrosion can begin pitting important parts and metal buildup on valve surfaces can cause improper ABS functioning.

The idea of brake systems corroding from the inside might seem surprising, but stop and think about it. If this process didn't occur between dissimilar metals in a fluid, batteries would not work. Consider that ABS possesses different metal parts all bathed in hydraulic fluid and it becomes easier to understand what's going on here, though at a much slower pace than in a battery. Because ABS circulates fluid when activated, any corrosion compounds that would stay isolated in a conventional brake system are quickly circulated throughout the system to eventually come in contact with important metal parts. If neglected this situation could eventually cause the brake system to rust-out from the inside.

All the research to date on corrosion in ABS indicates that as brake fluid corrosion inhibitors break down, copper used in the making of brake line tubing begins to accumulate in brake fluid - long before active corrosion begins to occur. In the 1990s, researchers were looking for a better, more reliable way of testing brake fluid than what had been available. The end result was the development of FASCAR (Fluid Analysis by Stimulation of Copper Alpha Reactions) technology.

The presence of copper ions in brake fluid is the basis of the FASCAR system of brake fluid analysis test strips. Copper is considered an “alpha” contaminant, meaning that it begins to accumulate prior to actual active metal corrosion. By measuring copper concentrations with a color change test strip, technicians can determine in as little as sixty seconds if active corrosion may be starting to occur in a customer's brake system. Even NHTSA has found that copper in brake fluid ultimately causes corrosion in ABS, affects important system components, and can result in extended braking distance. Their findings also suggest that copper builds up in fluid because it's present in the high pressure tubing used for brake lines and can be used as a measurable predictor of active corrosion.


This is all good news for your fixed ops department. Because brake fluid must be replaced - according to the MAP guideline - when copper reaches 200 ppm, and the only way to conveniently determine when that point has been reached is to test with a FASCAR test strip. Technicians now have a reliable and recognized tool to demonstrate to customers when their brake system needs flushing. Research into corrosion in ABS indicates that fluid should be tested after about twenty months in service and about every three months thereafter, or about as often as the oil is changed. This gives technicians the perfect opportunity to conduct a quick inspection and identify problems for customers before they occur, in turn building a stronger customer relationship.

Extended vehicle service intervals have reduced customer contact for most service departments. The new MAP guideline on brake fluid service in combination with the FASCAR brake fluid analysis system provides a perfect tool for recapturing some of that business. With the spread of ABS comes a new opportunity for shops to provide a new service to customers and strengthen these relationships.

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