28-21-13
 ALL  ú ú 04 Page 406 ú Oct 10/91
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 034-028
 (3)  Remove the nuts and washers (3 locations) that attach the valve unit to the rear spar.
 S 864-029
 WARNING: CAREFULLY DO ALL THE SAFETY PROCEDURES TO DEFUEL AND TO GO INTO
_______ THE FUEL TANKS. INJURY TO PERSONS AND DAMAGE TO EQUIPMENT CAN OCCUR IF YOU DO NOT OBEY THE SAFETY PROCEDURES.
 (4)  
Purge and prepare the center wing tank for entry (AMM 28-11-00/201).

 S 014-119

 (5)  
Go into the center wing tank (AMM 28-11-00/201).

 S 014-030

 (6)  
Remove the applicable spanwise beam access doors to get access to the valve unit (AMM 28-11-09/401).

 (a)  
For the removal of the left valve, remove the doors 131AZ, 131BZ, 131CZ, and 131DZ.

 (b)  
For the removal of the right valve, remove the doors 131AZ, 131BZ, 132AZ, and 132BZ.

 S 034-031
 (7)  
Remove the bolt, washers, and nut that attach the bonding jumper to the grounding lug on the valve unit.

 S 034-032

 (8)  
Remove the lockwire from between the outlet flange bolt and the inlet tube coupling nut.

 S 034-099

 (9)  
Remove the bolts and washers (4 locations) that attach the outlet tube to the valve unit.

 (10)
 Disconnect the outlet tube and the valve unit.

 S 034-033
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 28-21-13
 ALL  ú ú 04 Page 407 ú Oct 10/91
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 034-100
 (11)
 Remove the orifice plate and the gasket seal.

 S 034-034

 (12)
 Disconnect the inlet tube coupling from the valve unit.

 S 034-101

 (13)
 Discard the packing.

 S 024-035

 (14)
 Remove the valve unit and the spar gasket seal.

 TASK 28-21-13-004-036
 5.  Center Wing Tank Refuel Valve Unit Installation (Fig. 401)_______________________________________________
 A. References
 (1)  
AMM 28-11-00/201, Fuel Tanks

 (2)  
AMM 28-11-09/401, Spanwise Beam Access Door

 (3)  
AMM 28-21-02/401, Refuel Valve Control Unit

 (4)  
AIPC 28-21-02 Fig. 5

 B.
Access

 (1)  
Location Zones
 131 Center Section Wing Box, Left
 132 Center Section Wing Box, 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

 C.
Procedure

 S 214-077
 (1)  
Replace the spar gasket seal if one of these conditions occur:

 (a)  
There is damage on the spar gasket seal.

 (b)  
The spar gasket is not in the usual shape.

 (c)  
The spar gasket is too hard.

 S 424-078
 (2)  
Put and hold the gasket seal and the valve unit in the correct position on the rear spar.

 S 424-079

 (3)  
From outer side of the fuel tank, install the washers and nuts (3 locations) that attach the valve unit to the rear spar.

 (a)  
Tighten the nuts to 35-50 pound-inches.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 28-21-13
 ALL  ú ú 04 Page 408 ú Oct 10/91
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 (4)  S 424-080Install the bolt, washers, and nut to attach the bonding jumper to the grounding lug on the valve body (AMM 20-11-15/401).
 (5)  S 764-081Do a check on the bonding resistance between the valve unit and the structure (AMM 20-22-01/601).
　
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