NOTE:  No. 1 tank boost pump requires ac power. Provide airplane with external power.
NOTE:  If you must use the fuel boost pumps in the center tank, you must have a maintenance person or observer in the flight compartment to continuously monitor the LOW PRESSURE lights.  Turn the applicable fuel boost pump to the OFF position if the LOW PRESSURE light for the center tank stays on.
(9)  
Loosen fuel line at low-pressure inlet of APU fuel control unit just enough to allow trapped air to escape.

(10)
Position APU master switch to ON. (Do not go to START position). Operate fuel boost pump until air or preservation oil is forced from line and low pressure fuel filter. Catch dripping fuel in container. Tighten fuel line fitting and shutoff fuel boost pump. (Position master switch to OFF).

(11)
Manually close APU fuel shutoff valve at left rear wing spar.

(12)
Disconnect high-pressure fuel line from atomizer, connect fuel hose to disconnected line, and place open end of fuel hose into container.

(13)
Motor engine per par. 3.D., until fuel free from air bubbles and oil is discharged into container.

CAUTION: TO AVOID DAMAGING APU, OBSERVE OPERATING LIMITS (FIG. 201).
NOTE:  Clear fuel should normally appear within three motoring cycles.
(14)
Restore engine to operating condition per par. 3.E., but do not install lower shroud.

(15)
Start engine per par. 2.C.

(16)
Allow engine to accelerate to 100% service speed and operate at this speed for three to five minutes.

(17)
Shut down engine per par. 2.D.

(18)
Position BATTERY SWITCH to OFF and placard.

(19)
Check engine oil lines and fuel lines and their connection points for evidence of oil and fuel leakage.

(20)
Replace low-pressure fuel filter element (Fig. 202).

(a)  
Unscrew filter cap from filter head. Catch dripping fuel in suitable container.

(b)  
Remove and discard old filter element and packing.

(c)  
Remove backup ring and packing from filter head; discard packing.

(d)  
Wash filter cap and backup ring in solvent and dry thoroughly with clean compressed air.

WARNING:  SOLVENT IS TOXIC. USE IN WELL-VENTILATED AREA. KEEP AWAY FROM FLAME.

(e)  
Install new packing and backup ring in filter head.

(f)  
Install new packing on new filter element and install element in filter head.

(g)  
Install filter cap in filter head and safety wire.

(21)
Replace high-pressure fuel filter element (Fig. 202).

(a)  
Unscrew filter cap from fuel control unit.

(b)  
Remove filter element, spring, and packing.

CAUTION:  EXERCISE EXTREME CARE TO PREVENT ANY DIRT FROM ENTERING FUEL CONTROL UNIT.

(c)  
Clean filter cap and spring in solvent and dry thoroughly.

WARNING:  SOLVENT IS TOXIC. USE IN WELL-VENTILATED AREA. KEEP AWAY FROM FLAME.

(d)  
Install new packing on filter guide.

(e)  
Place new filter element, spring, and new filter cap packing in place and install filter cap in fuel control unit.

(f)  
Safety wire filter cap to fuel control unit housing.

(22)
Replace oil filter element (Fig. 202).

(a)  
Remove filter cap, packing, and filter element. Catch dripping oil in suitable container. Discard filter element and packings.

(b)  
Clean cap in solvent and dry thoroughly with clean, compressed air.

WARNING:  SOLVENT IS TOXIC; USE IN WELL-VENTILATED AREA. KEEP AWAY FROM FLAME.

(c)  
Lubricate and install new O-ring packing in filter element.

(d)  
Lubricate and install new O-ring packing on filter cap.

(e)  
Place filter element on centering boss of oil pump housing.

(f)  
Position filter cap over filter element and screw cap into oil pump housing. Tighten cap and lockwire.

513 
49-11-0 Page 208  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Sep 01/02 

500  Fuel and Oil Filter Installation 
Aug 15/80  Figure 202 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  49-11-0 Page 209 

CAUTION:  DO NOT EXCEED TORQUE VALUE OF 25 POUND-INCHES WHEN TIGHTENING OIL FILTER CAP.
(23) Purge fuel system per par. 5.
501 
49-11-0 Page 210  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Feb 20/88 
　
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