TB 9-6685-319-35
SECTION III
CALIBRATION PROCESS FOR HYDRAULIC GAGES
6. Preliminary Instructions
process. Personnel should become familiar with the entire bulletin before beginning the
calibration.
b. Items of equipment used in this procedure are referenced within the text by common
name and item identification number as listed in tables 2 and 3. For the identification of
equipment referenced by item numbers prefixed with A, see table 2, and for prefix B, see
c. Unless otherwise specified, verify the result of each test and, whenever the test
requirement is not met, take corrective action before continuing with the calibration.
Adjustments required to calibrate the TI are included in this procedure. additional
maintenance; information is contained in the manufacturer's manual for this TI.
d. Unless otherwise specified all controls and controls settings refer to the TI.
7. Equipment Setup
a. Remove pressure gage tester (A2) from carrying case.
b. Remove filler plug and fill pressure gage jester with hydraulic oil (MIL-L7870A).
c. Reinstall filler plug and secure pressure gage test to an adequate workbench. Level
pressure gage tester.
e. Thoroughly clean bourdon tube or diaphragm of TI. First, rotate TI and allow any
liquid which may be in the bourdon tube or diaphragm area to flow out. Using an eye
dropper or small glass tube, fill bourdon tube or diaphragm area with toluene, methyl
alcohol, or freon TF solution. Allow solution to remain in the gage for 5 minutes. Drain
gage and dry for at least 10 minutes.
f. If required, zero-adjust dial indicator of TI by removing retaining ring and
coverglass and adjusting the calibration screw.
8. 0 to 10,000 Psi Hydraulic Gages (0.1 to 20 Percent Accuracy)
a. Performance Check
(1) Connect equipment as shown in figure 1.
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