B.
References

 (1)  
AMM 12-11-01/301, Fuel Servicing

 (2)  
AMM 28-11-00/201, Fuel Tanks

 (3)  
AMM 28-31-01/401, Fuel Override/Jettison Motor/Impeller Unit

 (4)  
AIPC 28-31-07 Fig. 1, Item 50

 (5)  
Boeing Drawing 344U0052, Interchangeable Parts - 747 Fuel Pumps

 C.
Access

 (1)  
Location Zones 131 Center Section Wing Box, Left 132 Center Section Wing Box, Right 544 Inbd Main Tank (Part), Mid Spar to Rear Spar, Left 644 Inbd Main Tank (Part), Mid Spar to Rear Spar, Right

 (2)  
Access Panels
 131AZ Spanwise Beam Access Door
 131BZ Spanwise Beam Access Door
 131CZ Spanwise Beam Access Door
 131DZ Spanwise Beam Access Door
 132AZ Spanwise Beam Access Door
 132BZ Spanwise Beam Access Door

 D.
Procedure

 S 434-032
 (1)  
Do these steps to install the inlet check valve:

 (a)  
Make sure the inlet check valve is not bent or twisted (deformed).

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 747-400 MAINTENANCE MANUAL 
JETTISON PUMP FOR THE OVERRIDE/ INLET CHECK VALVE  DISCHARGE LINE 
SEE  A 
INLET VALVE CHECK  REAR SPAR 
BSEE WASHER SCREW (3 LOCATIONS) 

PUMP INLET LINE
LOCKWIRE
HOUSING
MOTOR/IMPELLER UNIT
AFT
INLET CHECK VALVE FOR THE OVERRIDE/JETTISON PUMP A
SPRING
(2 LOCATIONS)

PACKING
CAM
INLET CHECK VALVE
B

Fuel Override/Jettison Pump Inlet Check Valve Figure 401
L28783
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 (b)  
Put a new packing, lubricated with petrolatum, on the bottom of the inlet check valve. 1) Slightly stretch the packing before you put it in the

 groove.

 (c)  
Put the inlet check valve in its position on top of the override/jettison pump housing.

 (d)  
Install the screws and washers (3 locations) that attach the inlet check valve to the override/jettison pump housing.

 (e)  
Tighten the screws to a torque of 11-13 inches-pounds

 (1.2 - 1.5 newton-meters).
 (f)  Install lockwire on the inlet check valve screws.
 S 864-011
 (2)  
Go out of and close the fuel tank (AMM 28-11-00/201).

 E.
Leak Check of the Inlet Check Valve

 S 654-012
 (1) Completely refuel the applicable fuel tank (AMM 12-11-01/301).
 S 794-034
 CAUTION: DO NOT PULL THE MOTOR/IMPELLER UNIT AWAY FROM THE REAR SPAR
_______ UNTIL YOU INSTALL THE RETENTION SCREWS. THE RETENTION SCREWS WILL HELP YOU TO QUICKLY INSTALL THE MOTOR/IMPELLER UNIT AGAIN IF THERE IS A FUEL LEAK.
 (2)  
Install the retention screws (AMM 28-31-01/401).

 S 794-035

 (3)  
Pull the motor/impeller unit away from the rear spar
 (AMM 28-31-01/401).

 S 794-014

 (4)  
Do a check for leaks on the override/jettison pump housing and inlet check valve.

 S 414-015

 (5)  
Install the motor/impeller unit in the override/jettison pump housing (AMM 28-31-01/401).

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