505  Fuel Boost Pump Bypass Valve and Bypass Check Valve Installation 
Jun 20/89  Figure 401 (Sheet 1)  28-22-61 
Page 403 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

Fuel Boost Pump Bypass Valve and Bypass  505 
28-22-61  Check Valve Installation  Jun 20/89 
Page 404  Figure 401 (Sheet 2) 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

11  Install Fuel Boost Pump Bypass Check Valve (ALL EXCEPT airplanes with boost pump bypass valve with valve lock actuating arm) (Fig. 401)
A.  Clean machined surfaces of valve and fuel line flange with naphtha and wipe dry with lint-free cloth.
B.  Install new O-rings on bypass check valve and outlet line lightly lubricated with fuel.
C.  Position boost pump bypass check valve and tighten coupling above bypass check valve finger-tight.
D.  Position bypass check valve outlet line and tighten couplings at both ends finger-tight.
E.  Install bonding straps on bypass check valve and bypass check valve outlet line.
F.  Check electrical bond between bypass check valve and airplane structure and between bypass check valve outlet line and airplane structure per 20-22-01 I/C. Resistance shall not exceed
0.010 ohm.
G.  Carefully tighten all couplings so as to not stress the bypass check valve.
H.  Install fuel tank access panel (Ref 28-11-11 R/I).
505 
Jun 20/89  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  28-22-61 Page 405 

FUEL BOOST PUMP CHECK VALVE -REMOVAL/INSTALLATION
1.  General
A.  Removal/installation procedure for all of the fuel boost pump check valves is basically the same, the only differences being location and access. Tanks 1 and 2 each contain three valves. As the valves are located inside the tanks it is necessary to defuel the applicable fuel tank to gain access to any valve.
2.  Equipment and Materials
A.  Aliphatic Naphtha (Ref 20-30-31)
3.  Prepare Fuel Boost Pump Check Valve for Removal
A.  Defuel and purge applicable fuel tank (Ref 28-23-0, 28-10-0 MP).
WARNING:  DO NOT COMPROMISE THE SAFETY PRECAUTIONS GIVEN FOR PURGING AND FUEL TANK ENTRY.
B.  Gain access to valve to be removed through access panel No. 1 (Ref 28-11-11 R/I) and applicable rib access openings.
4.  Remove Fuel Boost Pump Check Valve
A.  Disconnect low pressure sensing line (Fig. 401)
B.  Remove fuel line mounting bolts and nuts.
C.  Remove fuel boost pump check valve mounting bolts.
CAUTION:  CHECK VALVE MUST NOT BE ALLOWED TO FALL BECAUSE DAMAGE TO WING SKIN MAY RESULT.
D.  Remove check valve and remove O-rings from check valve flanges.
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 28-22-71 Page 401 

5.  Install Fuel Boost Pump Check Valve
A.  Clean O-ring groove and machined surfaces of valve and mating surfaces with naphtha. Wipe dry with lint-free cloth.
B.  Install new O-rings, lightly lubricated with fuel, in check valve flanges.
C.  Position check valve in place and install mounting bolts and nuts.
D.  Install fuel line mounting bolts and nuts.
E.  Connect low pressure sensing line.
6.  Return Airplane to Normal
A.  Install access door(s) in rib openings, if previously removed.
B.  Install access panel (Ref 28-11-11 R/I).
C.  Fill tank with fuel (Ref 12-11-0 Fuel Servicing) and check access panel for leaks.

Fuel Boost Pump Check Valve Installation  569 
28-22-71  Figure 401  Jun 20/85 
Page 402 
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APU FUEL FEED LINE - REMOVAL/INSTALLATION
1. General
A.  The APU fuel feed line carries fuel from the engine fuel line or APU fuel line bypass to the APU. To simplify removal/installation, the APU fuel feed line is divided into four segments. The segment from the engine fuel feed line and APU fuel line bypass to the 70.85 rib web is contained within the No. 1 fuel tank and will be identified as the APU fuel feed line (No. 1 fuel tank). The segment from the 70.85 rib web to the center wing box upper skin is contained within the wing center section and will be identified as the APU fuel feed line (wing center section). The segment from the center wing box upper skin to the APU compartment is a flexible line, enclosed in a shroud and will be identified as the APU fuel feed line (flexible). The segment in the APU compartment, connecting the flexible line to the APU fuel filter installation, is enclosed in a shroud and will be identified as the APU fuel feed line (APU compartment).
　
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