MISCO DOT3 Brake Fluid Tester – Measure Brake Fluid Water Content and Estimate Boiling Point
The MISCO Palm Abbe Digital Brake Fluid Refractometer is a fourth generation digital refractometer designed for directly measuring water content, and estimating the boiling point of Standard DOT3 brake fluids. It only takes one or two drops of brake fluid to get an instant, accurate indication of percent water content and an estimate of it’s boiling point.
As part of the regular maintenance interval, many automobile manufacturers recommend regular brake fluid inspection. However, there was never an easy, inexpensive means for testing it; until now. A Brake Fluid Refractometer represents the most accurate field testing means available for determining the water content and estimating the boiling point of automotive brake fluids.
No Brakes – The Dangers of High Water Content in Brake Fluid:
A dangerous condition exists when brake fluid boils in the braking system; it can feel like air trapped in the lines when braking. In extreme cases the driver may be able to push the brake pedal completely to the floor without slowing or stopping the vehicle. In colder climates, brake fluid with high water content becomes very thick, which can also cause slow pedal response or difficulty braking. Also, as the water content in brake fluid increases, it will become more corrosive to steel pistons and the ABS modulator.
Easy To Use:
Place a drop of brake fluid from the master cylinder or wheel cylinder on the measuring surface, close the sample cover, allow a brief period of time for the temperature to stabilize, and press the button.
Even New Cars Contain Water in Their Brake Fluid!
It is well know that automotive brake fluid is “Hygroscopic.” This means that in a relatively short period of time, brake fluid will absorb moisture directly from the air; even in a sealed braking system.
The Society of Automotive Engineers (SAE) conducted a recent study of automotive brake fluid. They found that an average one-year-old car had 2% moisture in its brake fluid. Randomly tested cars in the U.S., with an average age of eight years, showed an average water content of greater than 2 ½%. Of these cars, 25% had a dangerously high water content of 4% or more.
The Result is Catastrophic Brake Failure!
Brake fluid with high water content has a reduced boiling point. This means that the brake fluid will boil in the wheel cylinder at a lower temperature than the braking system was designed for. When traveling down a steep grade, towing a trailer, or in the event a brake pad becomes stuck against a rotor, brake fluid temperature can increase high enough to boil if it contains enough water. Stepping on the brake pedal will now only compress the vapor instead of applying force to the pad – the result is sudden brake failure.
Brake Fluid’s Dirty Little Secret:
DOT Standard 116 requires that DOT3 brake fluid, with no moisture content, will only boil at temperatures above 400 °F (205 °C). The fluid in a 3-4 year old car with 3-4% water content in the brake fluid could boil at less than 300 °F (149 °C). How much water is too much? When should brake fluid be changed? Click here for a handy guide to brake fluid water content: When should brake fluid be changed?