(a)  
Tighten the jamnut (31).

 S 434-033
 (14)
 Install the tubes (23, 24, 25, and 26) that connect to the fan air modulating valve. Make sure the clampshells are installed between the tube and the clamp (27) (Fig. 401, Sheets 4 and 6).

 S 434-034

 (15)
 Install the fan-air-modulating valve (AMM 36-12-04/401).

 S 794-035

 (16)
 Apply the leak detector to all of the tube connections and the coupling installations.

 S 794-036

 (17)
 Dry motor the engine (AMM 71-00-00/201).

 (a)  
Examine the tube connections and the coupling installations for leakage. 1) Repair the tube connections if there is leakage. 2) If bubbles come slowly into view around the couplings (7),

 the quantity of leakage is satisfactory. 3) Repair the cause of the leakage if there is a high concentration of leakage from the coupling installation.
 F. Put the Airplane Back to Its Usual Condition
 S 414-037
 WARNING: OBEY THE INSTRUCTIONS IN THE PROCEDURE TO CLOSE THE THRUST
_______ REVERSERS. IF YOU DO NOT OBEY THE INSTRUCTIONS WHEN YOU CLOSE THE THRUST REVERSERS, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR.
 (1)  
Close the thrust reversers (AMM 78-31-00/201).

 (2)  
Close the core cowl panels (AMM 71-11-06/201).

 (3)  
Close the fan cowl panels (AMM 71-11-04/201).

 S 414-039
 S 414-047
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 (4)  S 444-048Do the activation procedure for the thrust reverser (AMM 78-31-00/201).
 (5)  S 414-040Close the mid lower (forward) access panel on the left side of the strut (AMM 54-62-00/201).
 (6)  S 864-041Remove electrical power if it is not necessary (AMM 24-22-00/201).

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 ENGINE BLEED AIR PRECOOLER - INSPECTION/CHECK
_____________________________________________
 1.  General_______
 A.  This procedure contains one task. It does a check of the precooler.
 B.  The precooler is installed on the bottom of the strut above the engine compressor case. It is necessary to open the core cowl panels and the thrust reverser halves to get access to the precooler.
 TASK 36-12-01-206-012
 2.  Examine the Precooler (Fig. 601)_____________________
 A.  References
 (1)
36-00-00/201, Pneumatic System

 (2)  
36-11-04/201, Engine Bleed Air Pressure Regulating and Shutoff Valve (PRSOV)

 (3)
36-12-01/401, Engine Bleed Air Precooler

 (4)
71-11-04/201, Fan Cowl Panels

 (5)
71-11-06/201, Core Cowl Panel

 (6)
78-31-00/201, Thrust Reverser System

 B.  
Access

 (1)  
Location Zone
 452 Engine 1 - Strut Torque Box
 462 Engine 2 - Strut Torque Box
 472 Engine 3 - Strut Torque Box
 482 Engine 4 - Strut Torque Box

 (2)  
Access Panel 415 and 416 Thrust Reverser Halves - Engine 1 417 and 418 Core Cowl Panels - Engine 1

 425 and 426 Thrust Reverser Halves - Engine 2 427 and 428 Core Cowl Panels - Engine 2
 435 and 436 Thrust Reverser Halves - Engine 3 437 and 438 Core Cowl Panels - Engine 3
 445 and 446 Thrust Reverser Halves - Engine 4 447 and 448 Core Cowl Panels - Engine 4
 C.  Prepare to Do the Check for the Precooler
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