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A
737-300/400/500MAINTENANCE MANUAL
 S 686-009
 (9)  If you find leakage, do these steps:
 (a)  
From the outer side of the wing tank located at the wing front spar remove these components (Fig. 601): 1) Remove the conduit nut. 2) Remove the nylon grommet. 3) Remove the rubber grommet.

 (b)  
Do a check to see if the leakage is from the inner surface of the conduit or the bulkhead union seal.

 (c)  
Use the flexible plastic tube and the vacuum source (a small syringe) to do the step that follows: 1) Remove the water or fuel that collected in the bottom of

 the conduit. 2) Put the flexible tube approximately 16 inches (406.4 millimeters) into the conduit. 3) Make sure the flexible tube is at the lowest point in the conduit. 4) Examine the fluid that you remove to see if the fluid contains fuel. 5) Fuel found in the conduit is an indication that there is a leak in the conduit.

 (d)  
Defuel the applicable fuel tank (AMM 28-23-00/201).

 WARNING: OBEY ALL OF THE FUEL TANK PURGING AND ENTRY PRECAUTIONS.
_______ INJURIES TO PERSONS AND DAMAGE TO EQUIPMENT CAN OCCUR.
 (e)  
Do this procedure: "Fuel Tank Purging and Entry"
 (AMM 28-10-00/201).

 (f)  
Remove the access panel, No. 11, for the applicable tank (AMM 28-11-11/401).

 (g)  
Remove the float switch conduit (AMM 28-21-71/401) to do an inspection.

 (h)  
If the fuel leakage is from the conduit, replace the necessary parts of the conduit assembly.

 (i)  
If the leakage is from the bulkhead union, do these steps: 1) Examine the bulkhead union to see if the union is

 serviceable. 2) Install a new O-ring on the bulkhead union. 3) Clean the bulkhead surface where the O-ring is to seal.

 (j)  
Install the float switch conduit (AMM 28-21-71/401).

 (k)  
Install the access panel, No. 11, that you removed before (AMM 28-11-11/401).

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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737-300/400/500MAINTENANCE MANUAL
 (l)  
Do one of these steps: 1) Move sufficient fuel from the other tanks to fill the

 applicable tank with fuel (AMM 28-23-00/201). 2) Fill the applicable tank with fuel (AMM 12-11-00/301).

 (m)  
Make sure the fueling float switch operates correctly (AMM 28-21-00/501).

 (n)  
Do a visual inspection of the bulkhead union for indications of leakage. 1) No leakage is permitted.

 S 416-012
 (10) Install the slat access panel.
 S 096-010
 WARNING: YOU MUST CORRECTLY INSTALL THE SAFETY LOCKS FOR THE LEADING AND
_______ THE TRAILING EDGE FLAPS. THE CONTROL SURFACES FOR THE LEADING EDGE AND THE TRAILING EDGE CAN MOVE QUICKLY. THIS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (11) Remove the safety locks from the leading edge flaps
 (AMM 27-81-00/201).

 S 866-011
 WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF THE LE
_______ AND TE FLAPS AND FLAP DRIVE MECHANISMS. THE CONTROL SURFACES FOR THE TRAILING EDGE AND THE LEADING EDGE CAN EXTEND AND RETRACT QUICKLY. THIS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (12) Retract the leading edge flaps (AMM 27-81-00/201).
 TASK 28-21-71-216-016
 3.  Center Tank Fueling Float Switch Wiring Inspection__________________________________________________
 A. Equipment
 (1)  Megohmmeter - Quad Tech 1864 (or equivalent), must be able to read resistance at 500 VDC
 B. Consumable Materials
 (1)  Sealant - Proseal 860
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
FUELING FLOAT SWITCH 
　
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