S 012-025-N00

 (5)  
Do the steps that follow to examine the No. 4 bearing compartment
 (rear) and cover for coke (Fig. 201).

 NOTE: Coke is a collected quantity of carbon that is black in
____ color, brittle, and has an irregular surface finish. Some of the coke can become flakes and fall away from the compartment walls. Loose coke is coke that you can easily remove with a vacuum or tweezers.
 (a)  Do a visual inspection of the eight oil supply holes as follows (Fig. 203): 1) Carefully remove all loose coke from the oil supply holes. 2) If you can not remove the coke from the holes do one of the
 steps that follow:
 a) Remove the engine from service immediately,

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SEE A
SEE B
NO. 4 BEARING 
COMPARTMENT 
A 
NO. 4 BEARING 
(OIL) NOZZLE 
KEYWASHER 
KEYWASHER 
BOLT 

BOLT  KEYWASHER  NO. 4 BEARING TRANSFER TUBE  KEYWASHER 
B  1 
2 1  ENGINES PRE-PW-SB 72-472 ENGINES POST-PW-SB 72-472  L-A3821 
No. 4 Bearing (Oil) Nozzle - Removal and Installation Figure 201 (Sheet 1) 

A47070
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////////////////////////A / PW4000 SERIES /747-400 / ENGINES /MAINTENANCE MANUAL ////////////////////////
WASHER  FRONT NO. 4 BEARING NOZZLE ASSEMBLY
PACKING TRANSFER TUBE (THE DAMPER TUBE TO THE FRONT NOZZLE)
RETAINER PLATE
CLEARANCE GAP
A
A
SCAVENGE
TUBE ASSEMBLY

B2
L-A8960
No. 4 Bearing (Oil) Nozzle - Removal and Installation
Figure 201 (Sheet 2)

E15880
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BOLT AND WASHER (2 LOCATIONS)
B-B

L-A8735
No. 4 Bearing (Oil) Nozzle - Removal and Installation Figure 201 (Sheet 3)
E15888
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////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
b)  Or, do the steps to clean the No. 4 bearing tubes and nozzle, and ferry the engine to a location where the engine removal is possible.
 (b) Do a visual inspection of the eleven oil drain holes as follows (Fig. 203): 1) Carefully remove all loose coke from the oil drain holes. 2) If the flow through three or more holes is decreased or fully stopped because of coke, remove the engine from service immediately. 3) If the flow through one or two holes is decreased or fully stopped because of coke, do one of the steps that follow: a) Remove the engine from service immediately, b) Or, do the steps to clean the No. 4 bearing tubes and
 nozzle, and ferry the engine to a location where the engine removal is possible.
 (c) If the No. 4 bearing compartment has coke on the bearing, cage or rollers, or on more than 50% of the compartment surfaces, do the steps that follow: 1) Do the Oil System Contamination Inspection (AMM 72-00-00/601). 2) Complete this procedure for the No. 4 bearing compartment and the No. 4 bearing oil nozzle, oil pressure, and scavenge tubes before you operate the engine. 3) After this procedure is completed, examine the oil tank magnetic plug after each 25 hours of service (AMM 79-21-10/601).
　
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