Replacement of the Hydraulic Control Unit Filter [CFMB]

TASK 78-31-51-920-001-A
Replacement of the Hydraulic Control Unit Filter

WARNING: WEAR A FACE SHIELD WHICH IS RESISTANT TO HIGH PRESSURE JETS WHEN YOU WORK ON PRESSURIZED SYSTEMS.

WARNING: DO NOT GET THE FLUID ON YOUR SKIN OR IN YOUR EYES. IF YOU DO:

FLUSH IT AWAY WITH CLEAN WATER
GET MEDICAL AID.

CAUTION: MAKE SURE THERE IS NO UNWANTED MATERIAL IN THE PORTS AND ORIFICES OR DAMAGE CAN OCCUR.

CAUTION: YOU MUST INSTALL HYDRAULIC TUBES WITH HYDRAULIC FLUID AS LUBRICANT.

FIN: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 1M(3 FT)
No specific	AR	CONTAINER 4 L (1 USGAL)
No specific	AR	WARNING NOTICE(S)

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP2245)	finish paint EA4 blue 5991
(Material No.CP8001)	lockwire 0.032 in. (0.8 mm) dia.
(Material No.CP8002)	lockwire 0.032 in. (0.8 mm) dia

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 462AR

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
10	FILTER CARTRIDGE	AIPC 78-31-51-02-130

E. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 78-30-00-081-041-B	Make the Thrust Reverser Serviceable after Maintenance
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-30-00-710-040-B	Thrust Reverser Hydraulic System Bleed Procedure
TASK 78-31-00-710-042-A	Operational Test of the Thrust Reverser System
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
TASK 78-36-00-410-040-B	Closing of the Thrust Reverser Doors
Hydraulic Control Unit Filter
FOR [1000EM1] (ENGINE-1)
TASK 29-10-00-863-002-A	Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-864-001-A	Depressurize the Green Hydraulic System
FOR [1000EM2] (ENGINE-2)
TASK 29-10-00-863-003-A	Pressurize the Blue Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-003-A-01	Pressurize the Blue Hydraulic System with the Blue Electric Pump
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System

3. Job Set-up
Subtask 78-31-51-941-050-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 78-31-51-864-050-A ** ON A/C NOT FOR ALL

B. Depressurization of the Hydraulic System
(1) FOR [1000EM1] (ENGINE-1)
(a) Depressurize the Green hydraulic system (Ref. AMM TASK 29-10-00-864-001).
(2) FOR [1000EM2] (ENGINE-2)
(a) Depressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002).
(3) Put a WARNING NOTICE(S) in position to tell persons not to pressurize the applicable system.

On the panel 40VU.
On the ground service panel of the applicable hydraulic system.

Subtask 78-31-51-010-050-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-040):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Put the ACCESS PLATFORM 1M(3 FT) in position.

Subtask 78-31-51-040-050-A ** ON A/C NOT FOR ALL

D. Make the right thrust reverser unserviceable (Ref. AMM TASK 78-30-00-481-041).

Subtask 78-31-51-010-051-A ** ON A/C NOT FOR ALL

E. Open the right thrust reverser door (Ref. AMM TASK 78-36-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
452AR
(2) FOR [1000EM2] (ENGINE-2)
462AR

4. Procedure
Subtask 78-31-51-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Hydraulic Control Unit (HCU) Filter
(1) Put a CONTAINER 4 L (1 USGAL) under the HCU filter.
(2) Remove and discard the lockwire.
(3) Remove the filter bowl:

WARNING: YOU MUST REMOVE THE FILTER BOWL CAREFULLY BECAUSE IT IS FULL OF HYDRAULIC FLUID AND INJURY CAN OCCUR.

(a) Remove the filter bowl (5) from the HCU (15).
(4) Remove the filter cartridge (10) from the filter bowl (5). Discard the filter cartridge.

Subtask 78-31-51-420-050-A ** ON A/C NOT FOR ALL

B. Installation of the Hydraulic Control Unit Filter
(1) Put a new AIPC 78-31-51-02-130 FILTER CARTRIDGE (10) into the filter bowl (5).
(2) Fill the filter bowl (5) with thrust reverser hydraulic fluid.
(3) Install the filter bowl on the HCU. Tighten the filter bowl with your hand.

NOTE: Apply a witness line of finish paint EA4 blue 5991 (Material No.CP2245) after the filter bowl is tighten.

(4) Safety the filter bowl with CP8001lockwire 0.032 in. (0.8 mm) dia. or CP8002lockwire 0.032 in. (0.8 mm) dia.
(5) Remove the drain can.

Subtask 78-31-51-863-050-A ** ON A/C NOT FOR ALL

C. Pressurization of the Hydraulic System

WARNING: PRESSURIZATION OF THE HYDRAULIC SYSTEM CAN RESULT IN INADVERTENT THRUST REVERSER OPERATION. REMOVE ALL PERSONNEL FROM THE AREA AROUND THE THRUST REVERSER BEFORE THE HYDRAULIC SYSTEM IS PRESSURIZED. FAILURE TO COMPLY CAN RESULT IN INJURY TO PERSONNEL.

(1) Do the steps that follow:
(a) FOR [1000EM1] (ENGINE-1)
pressurize the Green hydraulic system (Ref. AMM TASK 29-10-00-863-002).
(b) FOR [1000EM2] (ENGINE-2)
pressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-003). The red clogging indicator is not extended.

Subtask 78-31-51-410-057-A ** ON A/C NOT FOR ALL

D. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the right thrust reverser cowl door (Ref. AMM TASK 78-36-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
452AR
(b) FOR [1000EM2] (ENGINE-2)
462AR

Subtask 78-31-51-440-052-A ** ON A/C NOT FOR ALL

E. Make the thrust reverser serviceable (Ref. AMM TASK 78-30-00-081-041).

Subtask 78-31-51-869-053-A ** ON A/C NOT FOR ALL

F. Bleed the air from the thrust reverser hydraulic system (Ref. AMM TASK 78-30-00-710-040).

Subtask 78-31-51-210-052-A ** ON A/C NOT FOR ALL

G. Examine the Filter Clogging Indicator on the HCU
(1) If the red end of the indicator is extended, set it to the operational position, as follows:
(a) Remove the retaining ring and the glass bowl from the HCU.
(b) Push the red indicator in to set the normal (operational) position.
(c) Install the glass bowl and the retaining ring.
(d) Safety the retaining ring with CP8001lockwire 0.032 in. (0.8 mm) dia. or CP8002lockwire 0.032 in. (0.8 mm) dia.
(2) Do one more deploy-to-stow cycle of the thrust reverser.
(3) Make sure that the clogging indicator on the HCU is in the operational position.

Subtask 78-31-51-710-050-A ** ON A/C NOT FOR ALL

H. Do an operational test of the thrust reverser system (Ref. AMM TASK 78-31-00-710-042).

5. Close-up
Subtask 78-31-51-410-052-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close fan cowl doors (Ref. AMM TASK 71-13-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:25:30 UTC