(c)  
Remove the lockwire that attaches the No. 4 bearing scavenge tube heat shield to the tube. 1) Remove the heat shield (front and rear) from the tube.

 (d)  
Remove the lockwire and bolts that attach the No. 4 bearing tube guide to the case.

 (e)  
While you hold the adapter with a wrench, disconnect the nut that attaches the tube to the adapter.

 (f)  
Move the tube radially to the inside to remove it from the case.

 (g)  
Install covers on the openings.

 S 162-011-N00
 (11)
 Clean the bearing compartment pressure oil passage way.

 (a)  
Apply air at a minimum pressure of 10 psig (68.9 kPa) through the adapter to the passage way of the pressure supply core in the bearing compartment.

 NOTE: The air will clean the passage way of any coke flakes
____ that possibly fell through the pressure tube during the removal.
 1) Make sure that the passage way is fully open. 2) Air leaks are permitted, because this is not a test.
 S 162-012-N00
 (12) Clean the tubes internally, as necessary.
 NOTE: The tubes must be removed before they can be cleaned.
____
 CAUTION: DO NOT USE COMPRESSED AIR OR A CABLE THAT TWISTS TO CLEAN
_______ THE TUBES. IF YOU USE THE WRONG PROCEDURES, YOU CAN CAUSE DAMAGE TO THE TUBES.
 (a) Clean the tubes internally with an applicable tube brush.
 NOTE: Alternatively, you can clean the tubes in a vapor or
____
 solvent degreasing fluid.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
S 212-013-N00
 (13)
 Examine the tubes for cracks.

 (a)  
Make sure you examine the area near the middle support spacer on the tubes.

 (b)  
Repair or replace tubes with cracks or bad distortion.

 S 162-014-N00
 (14)
 With a tube brush, remove all loose coke from the No. 4 bearing compartment.

 (a)  
Make sure you remove all loose coke which can block the scavenge tube.

 S 412-026-N00
 (15) ENGINES PRE-PW-SB 72-472; Install a clean No. 4 bearing oil nozzle and No. 4 bearing transfer tube as follows (Fig. 201):
 NOTE: It is not necessary to do an oil flow or airflow test on the
____
 clean oil nozzle before or after the installation.

 (a)  
Install a clean No. 4 bearing nozzle into the port in the pad on the exhaust case rear inner diameter. 1) Attach the nozzle with two bolts, lubricated with engine

 oil, and two washers.
 2) Tighten the bolts with your hand.

 (b)  
Install the No. 4 bearing transfer tube through the port in the nozzle and into the port in the exhaust case rear flange. 1) Attach the transfer tube with two bolts, lubricated with

 engine oil, and washers.
 2)  Tighten the bolts to attach the nozzle to the exhaust case and bolts to attach the transfer tube to the nozzle to 75-85 pound-inches (8.474-9.604 newton-meters).
 3)  Bend the tabs of the key washers.
 S 412-031-N00
 (16) ENGINES POST-PW-SB 72-472;
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
Install a clean No. 4 bearing (oil) nozzle and No. 4 bearing damper supply tube as follows (Fig. 201):
 (a)  
Install the No. 4 bearing nozzle in the port in the pad on the rear inner diameter of the exhaust case at the 1:30 o'clock position. 1) Install the nozzle with two bolts, with threads lubricated

 with engie oil, and two washers.

 (b)  
Install the No. 4 bearing damper supply tube through the 0.380 inch (9.652 mm) diameter hole in the nozzle and into the port in the rear flange of the exhaust case. 1) Install the damper tube with two bolts, with threads
　
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