(3) In the event of a continuous pressure drop in either cylinder due to leaks, soap suds should be applied to all thread connections * * * base shop for repair.

b. To charge the equilibrators with nitrogen.-Retract valve opener on the filling tube to prevent the escape of gas already in the equilibrator. Remove tee cap from filling tube, and attach flexible tube (C419, fig. 5). Connect flexible tube to nitrogen cylinder. Check to make sure air release valve is closed. Then screw in valve opener until the lifting of the equilibrator filling valve (fig. 11) from its seat can be felt. Open nitrogen cylinder valve slightly to allow gas to flow into equilibrator very slowly. Close nitrogen cylinder valve when the required equilibrator pressure is indicated on pressure gage. Retract valve opener to allow equilibrator valve to seat. Disconnect flexible tube and replace tee cap on filling tube. Again turn valve opener handle to open equilibrator valve and observe the pressure on the gage. If the pressure is greater than desired, open release valve and allow a slow escape of gas until the proper pressure is indicated, then reseat equilibrator valve. Remove air filling tube and replace closing plug. The pressure in both equilibrators should always be the same.

c. To relieve accumulated air in the head..