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$279.99 DOT3 Brake Fluid Refractometer Boiling Point °F Toyota Ford GM BMW VW

National Industrial Supply

  • $ 27999
  • Save $ 70

Item Description: Portable DOT-3 Brake Fluid Refractometer,  Fahrenheit Version


Product Specs:

* Dual Scales:
---> (1)Standard DOT 3: Boiling Point - 250'F to 500'F & 1-6% Water
---> (2)High Temp (Fords & Racing): Boiling Point - 250'F to 570'F & 1-6% Water
* Accuracy: +/- 0.50% Water
* Divisions: 1% Water
* Manual Temperature Compensation (MTC)
* Sturdy design

Included are: a pipette for dropping test fluids onto the prism (never dip the refractometer into the test fluid!), a mini screwdriver for scale calibration, and a Users Guide.

Advice:  It is strongly advised that you have a good thermometer to accompany this unit.  Since it is Manual Temperature Compensation, you will need to know your ambient temperature and adjust the Refractometer to match the temp.  If the Refractometer is not set properly, your results could be compromised!  The further the actual ambient temperature is from the setting on the Refractometer, the more inaccurate the results.  Don't skimp on the thermometer!


This unit comes with a 2 Year Warranty and friendly advice (if you ever need it)!

Many automobile manufacturers recommend regular brake fluid inspections, but until now there was never an easy, inexpensive means for testing it. Some of them recommend changing the brake fluid every 12 months, while others recommend changing every 24 months. The amount of moisture that brake fluid absorbs depends on a number of factors including the type of fluid, humidity, type of brake hoses, condition of the seals and mileage. The Fluid itself is "Hydroscopic", which means that it will suck up any water from any source. This inherent feature of the Brake Fluid will ultimately result in its failure unless changed.

Generally, brake fluid will absorb 1% or more moisture per year of service life. A two year old car will have 2-3% water in the brake fluid. 2% water reduces the boiling point of DOT3 brake fluid by approximately 135 degrees Fahrenheit (75 degrees Celsius). 2% water in DOT4 brake fluid reduces boiling point by 81 degrees Fahrenheit (45 degrees Celsius).

The Brake Fluid Tester represents the most accurate field testing means available for determining the boiling point and water content of brake fluids. No Brakes!
When brake fluid boils, the effect on performance is the same as having air in the system -- the pedal can travel to the floor without slowing or stopping the vehicle. At lower temperatures, brake fluid with a high water content can cause slow or difficult brake pedal response because it becomes more viscous. As the water content rises it will become more corrosive.

Recommended for maintaining American, German and some Japanese Cars!

Even New Cars Contain Water in Their Brake Fluid!
Over a relatively short period of time, brake fluid will absorb moisture from the air. A filed study conducted by the Society of Automotive Engineers (SAE) indicated that an average one year old car has two percent moisture in it's brake fluid. A random test of vehicles in the U.S. showed an average water content of 2.6% for cars with an average age of eight years. 25% of these cars had water content of 4% - dangerously high!

The Dangers of High Water Content In Brake Fluid
Brake fluid must flow freely to be effective. In cold weather brake fluid with high water content is very viscous, causing slow pedal response and requiring more effort. Water in brake fluid can also cause corrosion of steel pistons and ABS modulators. Most importantly, brake fluid with high water content has a reduced boiling point which creates a vapor by boiling in the wheel cylinder.

The Result is Catastrophic Brake Failure!
Boiling can occur when traveling down a steep grade, towing a trailer or when a brake pad is stuck against a rotor. Under these conditions rotor temperature can climb high enough to boil brake fluid with high water content. Stepping on the brake pedal will now only compress the vapor instead of applying force to the pad and results in sudden brake failure.

Calibrate this unit against factory sealed, virgin DOT 3 Brake Fluid.  This Fluid will have no Water in it, therefore your readings should correspond and read 0% Water .  If it doesn't, reset the unit to 0%.  Be sure that your outside temperature matches the dial on your unit.  Voila!  All done!


High Quality!

Each item is carefully manufactured and inspected to insure a long life in use. This item comes with a TWO YEAR WARRANTY against defects. Simply put, if it fails you, you get a replacement for FREE. An eBay first for quality Refractometers! No one backs their products like we do!



National Industrial Supply
30777 Rancho California #891420
Temecula, CA 92589, USA
Sales: 951.308.9269
Fax: 310.733.5480  -  E-mail:  -  Website: