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Brake Fluid Refractometers DOT4

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Brake Fluid Refractometers can only used for measuring brake fluid DOT-4. Brake Fluid Refractometers are precision optical testing instruments for measuring the boiling point and present water content of DOT4 brake fluids. In seconds and with only two drops of brake fluid an accurate indication of the boiling point or percentage of water content can be obtained. Brake fluid may be measured from the master cylinder or each of the wheel cylinders. Many automobile manufacturers recommend regular brake fluid inspections, but until now there was never an easy, inexpensive means for testing it. The Brake Fluid Tester represents the most accurate field testing means available determining the boiling point and water content of brake fluid.

Measuring Range: 1-6% Water & Boiling Point
Minimum Scale: 0.5% or Degrees C
Accuracy: ±0.5%
1.      Turn the Temperature Adjustment to the current ambient room temperature ( Degrees Centigrade ). Open the Daylight Plate, and place 2-3 drops of distilled water or calibration liquid on the Main Prism. Close the Daylight Plate so the liquid spreads evenly across the entire surface of the prism without any air bubbles or dry spots. Allow the samples to rest on the prism for approximately 30 seconds before going to step 2. This allows the sample to adjust to the ambient temperature of the refractometers.
2.      Hold the Daylight Plate in the direction of a light source and look into the eyepiece. You will see a circular field with graduation down the center (you may have to adjust the focus of the eyepiece to see the graduations clearly). The upper portion of the field should be blue, the lower portion should be white.
3.       Look into the eyepiece and turn the Calibration Screw until the boundary between the upper blue field and the lower white field meet exactly on the center of the scale, as shown in Fig.2, below. Be sure that ambient room temperature is correct for the solution you are using (20 Degrees Centigrade). When the working temperature of the room or environment that the unit is being used in (not the temperature of the sample) changes by more than 1 Degrees C, we recommend that the unit be recalibrated to maintain accuracy and reproducibility.
4.      Repeat Step 1, above, using the fluid you will be measuring instead of the distilled water / calibration fluid. Then do Step 2 and 3. When you do Step 3, the reading is read from where the blue / white boundary crosses the graduated scale. The scale provides a direct reading of the brake fluid.
5.       After measurement, clean the surface of the prism and the cover with a moist gauze cloth. After drying, store in the supplied case.
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