D.
Procedure

 S 434-006
 (1)  
Lightly lubricate the new O-ring with petrolatum and install it on the check valve.

 S 424-007

 (2)  
Put the check valve into its position on the end of the drain line used for the surge tank.

 S 434-008

 (3)  
Tighten with your hand the coupling that connects the valve to the drain line.

 NOTE: Not one of the threads can show.
____
 S 434-011
 (4)  
Connect a lockwire into the hole found on the top of the check valve with the two drilled-head screws that are through the tube assembly flange.

 (5)  
Get out of the fuel tank and close the fuel tank (AMM 28-11-00/201).

 S 864-010
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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 ALL  ú ú 01 Page 403 ú Oct 10/94
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 WING SURGE TANK PRESSURE RELIEF VALVE - MAINTENANCE PRACTICES
_____________________________________________________________
 1.  General_______
 A.  This section supplies instructions to do two tests on the pressure relief valves.
 (1)  
The first task uses a pressure check fixture to do a pressure check of the pressure relief valves.

 (2)  
The second task manually operates the pressure relief valves to make sure the valves opens and closes correctly.

 (3)  
The surge tank pressure relief valve check fixture is referred to as the check fixture in this procedure.

 TASK 28-13-05-702-023
 2.  Wing Surge Tank Pressure Relief Valve - (Pressure) Test_______________________________________________________
 A.  Special Tools and Equipment
 (1)  
G28005-14 Fixture, Surge Tank Pressure Relief Valve Check

 B.  
Standard Tools and Equipment

 (1)  
Pressure Source - capable of providing +1.5 psig, local purchase

 (2)  
Vacuum Source - capable of maintaining vacuum of -4.0 psig, local purchase

 C.  
References

 (1)  
IPC 28-11-02 Fig. 8

 D.  
Access

 (1)  
Location Zone 555 Surge Tank, Front Spar to Rear Spar, Left 656 Surge Tank, Front Spar to Rear Spar, Right

 E.  
Procedure

 S 032-005
 (1)  
Remove the four applicable bolts from the access door for the wing surge tank where the check fixture is attached.

 S 482-006

 (2)  
Put the check fixture bolts into the access door bolt holes and install the check fixture to the access door.

 (3)  
Connect the pressure source to the check fixture.

 (4)  
Slowly apply the positive pressure.

 S 492-007
 S 862-008
 NOTE: Make sure the positive pressure is not more than +1.25 psig.
____
 S 222-009
 (5)
Make sure that the valve opens between +1.0 and +1.25 psig.

 (6)  
Put the pressure back to 0 psig.

 S 862-010
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 28-13-05
 ALL  ú ú 01 Page 201 ú Feb 10/94
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 S 092-011
 (7)
Remove the pressure source and the check fixture.

 S 822-012

 (8)
Pull the T-handle down and set the valve.

 S 212-013

 (9)
Make sure that the valve poppet is in the center of the seat.

 S 082-014

 (10)
 Install the check fixture and the vacuum source.

 S 862-015

 (11)
 Slowly apply the vacuum pressure.

 NOTE: Do not apply a vacuum of more than -4.50 psig.
____
 S 222-016
 (12)
 Make sure the valve opens between -3.5 and -4.50 psig.

 S 862-017
　
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