TM 5-1940-321-13&P
( 5 ) Unscrew diffuser using a crescent wrench.
( 6 ) Disassemble the "O-Ring" and check as per 5-16-B
( 7 ) Clean outside threads with brush & solvent.
( 8 ) Verify the threads are in good repair.
( 9 ) Clean inside threads without solvent, use a soft toothbrush.
( 10 ) Reassemble, torque base to 25-30 ft lbs.
5-17. SCHEDULED PERFORMANCE TEST. The IAB requires only one scheduled performance test,
the pressure retention test. The following paragraphs provide procedures for this test, which is performed
by unit personnel.
5-18. PRESSURE RETENTION TESTS.
Materials Required:
Clipboard
Test Data Sheets, Pressure Retention
(copy of figures 5-22 and 5-23)
Pencil
Thermometer, Outdoor
Pressure Gauge, Shop
Clock or Watch
Tools Required:
None
Parts Required:
None
Parts to be Available:
None
a. Test Frequency. A pressure retention test must be performed on the craft semiannually by
unit maintenance personnel. The test is also performed whenever and air leak is suspected. The retention
pressure test determines if the buoyancy tubes and keel meet specifications for retaining pressure. A craft
that does not pass the pressure retention test will require a leak test and corrective maintenance.
Perform retention test as follows:
NOTE:
Use a shop pressure gauge, P/N 7111, rather than the pressure gauge supplied
in the repair kit.
5-32
