(2)  
Pressurize hydraulic system A, using system A engine-driven pump (Ref 29-11-0 Maintenance Practices).

(3)  
With engine operating at idle or above, indicated no flow system A pressure should be between 2900 and 3100 psi with flight control switches OFF and ground interconnect valve CLOSED.

(4)  
Place system A depressurization switch on overhead panel in OFF position. Allow system pressure to bleed off.

(5)  
Place depressurization switch in ON position. System pressure should return to normal.

(6)  
After completion of test, return system to normal configuration.

501 
Aug 01/75  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  29-11-32 Page 501 

SYSTEM A HYDRAULIC PUMP CASE DRAIN FILTER - UNIT SERVICING
1.  General
A.  The hydraulic pump case drain filter element should be removed and checked at regular intervals. Between these intervals the magnetic plug in the filter case should be removed and checked for metal contamination. If excessive metal is found, the associated pump should be removed and the system checked and flushed (Ref 29-11-0, Hydraulic System A - MP and I/C).
B.  A container will be necessary to catch fluid when disconnecting hydraulic lines. Should any fluid
spill, decontaminate (Ref Chapter 12, Cleaning and Washing).
Equipment and Materials

A.  Skydrol Assembly Lube - MCS 352 or Hydraulic Fluid BMS 3-11 (Ref\20-30-21)
3.  Service Hydraulic Pump Case Drain Filter
A.  Check Case Drain Filter Magnetic Plug
(1)  
Open engine right cowl panel.

(2)  
Depressurize hydraulic reservoirs (Ref 29-09-300 MP).

(3)  
Unscrew magnetic plug (7, Fig. 301) and check for metal contamination on plug, and in hydraulic fluid lost during removal of plug.

(4)  
Place new O-ring (8) on magnetic plug (7). Apply assembly lube or hydraulic fluid to 0-ring and threads of magnetic plug, then screw magnetic plug into drain plug (6). Hold drain plug and tighten magnetic plug to 15-20 pound-inches.

(5)  
Lockwire magnetic plug and drain plug.

500 
May 15/78  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  29-11-41 Page 301 

F86964
System A Hydraulic Pump Case Drain Filter Servicing  500 
29-11-41  Figure 301  Jun 20/87 
Page 302 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

B.  Remove Case Drain Filter Element
(1)  
Open engine right cowl panel.

(2)  
Depressurize hydraulic reservoirs (Ref 29-09-300).

(3)  
Unscrew filter bowl (4, Fig. 301) from filter head (1). Remove bowl with filter element (3).

(4)  
Remove filter element and spring (5). Check element and bowl for metal contamination.

(5)  
Replace paper filter element (3) and clean filter bowl (4), magnetic plug and spring.

C.  Install Case Drain Filter Element
(1)  
Insert backup ring, O-ring and backup ring (10, Fig. 301) into internal filter head groove. Lubricate with assembly lube or hydraulic fluid.

(2)  
Insert O-ring (2) in filter element groove.

(3)  
Install spring (5) and filter element (3) in filter bowl (4).

(4)  
Lubricate threads lightly with assembly lube or hydraulic fluid and screw filter bowl (4) into filter head (1). Apply a torque of 50 to 75 pound-inches to filter bowl and lockwire.

(5)  
Operate applicable engine-driven hydraulic pump and check filter for leaks. Refer to 71-09-100, Power Plant (JT8D) - Operating Procedures.

(6)  
Close engine cowl.

500 
Jun 20/87  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  29-11-41 Page 303 

SYSTEM A HYDRAULIC PUMP CASE DRAIN FILTER - REMOVAL/INSTALLATION
1.  General
A.  The maintenance practices for the system A hydraulic pump case drain filters installed on engines No. 1 and 2 are identical, except for unit location.
B.  A container will be necessary to catch any fluid when disconnecting hydraulic lines. Should any fluid spill, decontaminate (Ref Chapter 12, Cleaning and Washing).
2.  Equipment and Materials
A.  Skydrol Assembly Lube - MCS 352 or Hydraulic Fluid - BMS 3-11
3.  Remove Case Drain Filter
A.  Depressurize hydraulic reservoirs (Ref 29-09-300 MP).
B.  Open engine right cowl panel.
　
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