Replacement of the Main Gearbox (MGB) Stud and Lock Rings [PW11]

TASK 72-61-01-960-805-A
Replacement of the Main Gearbox (MGB) Stud and Lock Rings

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

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

REFERENCE	QTY	DESIGNATION
No specific	1	DRILL-REMOVAL TOOL
No specific	2	INSTALLATION TOOL - STUD

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.P06-019)	Lubricant, Bolt

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR, 461AL, 462AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 29-11-51-000-805-A	Removal of the Green Engine Driven Pump
TASK 29-11-51-400-805-A	Installation of the Green Engine-Driven Pump
TASK 29-13-51-000-806-A	Removal of the Yellow Engine Driven Pump
TASK 29-13-51-400-806-A	Installation of the Yellow Engine-Driven Pump
TASK 70-28-00-910-803-A	SPOP 42 - Chromate Conversion Coating of Aluminum
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
TASK 71-13-00-010-802-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-802-A	Closing of the Fan Cowl Doors
TASK 73-11-01-000-801-A	Removal of the Integrated Fuel Pump and Control (IFPC)
TASK 73-11-01-400-801-A	Installation of the Integrated Fuel Pump and Control (IFPC)
TASK 73-11-02-000-801-A	Removal of the Fuel Manifold
TASK 73-11-02-400-801-A	Installation of the Fuel Manifold
TASK 78-30-00-040-805-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-30-00-440-805-A	Reactivation of the Thrust Reverser System after Ground Maintenance
TASK 78-36-00-010-802-A	Opening of the Thrust Reverser Cowl-Doors
TASK 78-36-00-410-802-A	Closing of the Thrust Reverser Cowl-Doors
Replacement of the Main Gearbox (MGB) Stud and Lock Rings

3. Job Set-up
Subtask 72-61-01-941-057-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833)

Subtask 72-61-01-010-069-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR

Subtask 72-61-01-040-057-A ** ON A/C NOT FOR ALL

C. Deactivation of the Thrust Reverser for Ground Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for ground maintenance (Ref. AMM TASK 78-30-00-040-805).

Subtask 72-61-01-010-070-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL 462AR

4. Procedure

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

Subtask 72-61-01-020-052-A ** ON A/C NOT FOR ALL

A. Removal of the Component that follow
(1) Remove the hydraulic pump (Ref. AMM TASK 29-11-51-000-805) and (Ref. AMM TASK 29-13-51-000-806).
(2) Remove the Integrated Fuel Pump and Control (IFPC) (Ref. AMM TASK 73-11-01-000-801).
(3) Remove the fuel manifold (Ref. AMM TASK 73-11-02-000-801).

Subtask 72-61-01-960-050-A ** ON A/C NOT FOR ALL

B. Replacement of the Main Gearbox (MGB) Stud and Lock Rings
(1) Remove the studs and lock rings from the main gearbox housing as follows. See the sheet 1 of the figure

Replacement of the Main Gearbox (MGB) Stud and Lock Rings ** ON A/C NOT FOR ALL

(a) Install the DRILL-REMOVAL TOOL (BT 308 Removal Tool) into the chunck of a drill press and lower onto the stud shank before you start the drill press operation. See the sheet 2 of the figure

Replacement of the Main Gearbox (MGB) Stud and Lock Rings ** ON A/C NOT FOR ALL

NOTE: If the nut end of the stud is bent or too long for the DRILL-REMOVAL TOOL (BT 308 Removal Tool) remove a sufficient quantity of the stud shank to supply a pilot for the DRILL-REMOVAL TOOL (BT 308 Removal Tool).

(b) Drill, but not fully, through the lock ring. While you drill, frequently lift the DRILL-REMOVAL TOOL (BT 308 Removal Tool) to remove debris from the cutting teeth.

NOTE: For the best result, do not drill fully through the lock ring.

Replacement of the Main Gearbox (MGB) Stud and Lock Rings ** ON A/C NOT FOR ALL

NOTE: Continued pressure on the stud will force the lock ring out.

(d) Reduce the diameter of the lock ring with a drift if you cannot remove the lock ring.
(2) Install the studs and lock rings to the MGB housing as follows. See the sheet 4 of the figure

Replacement of the Main Gearbox (MGB) Stud and Lock Rings ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE STUDS ARE INSTALLED ON THE MAIN GEARBOX HOUSING AT THE CORRECT DEPTH. A STUD THAT IS NOT CORRECTLY INSTALLED CAN CAUSE AN INCORRECT LOCK BETWEEN THE STUD AND THE LOCK RING. IF YOU DO NOT OBEY THIS CAUTION, DAMAGE TO THE ENGINE PARTS CAN OCCUR.

(a) Apply P06-019Lubricant, Bolt or equivalent to the stud threads.
(b) Installation of the stud as follows:
1 Install the stud into the housing fingertight.
2 Install the stud to the housing to a depth of 0.010 in. (0.254 mm) to 0.020 in. (0.508 mm) with the INSTALLATION TOOL - STUD (R1107XW) Wrench.

NOTE: The studs must be perpendicular to the flat adjacent flange surfaces not more than 0.014 in. (0.356 mm) for each 4.0 in. (101.60 mm).

3 Align the new lock ring splines with the main gearbox housing splines if necessary.
4 Install the lock ring to a depth of 0.005 in. (0.127 mm) to 0.010 in. (0.254 mm) with the INSTALLATION TOOL - STUD (SF5902-5D) Installation Tool.
5 Touch-up the protective anodize coat around the stud by SPOP 42 if necessary (Ref. AMM TASK 70-28-00-910-803).

Subtask 72-61-01-410-067-A ** ON A/C NOT FOR ALL

C. Installation of the Components that follow
(1) Install the fuel manifold (Ref. AMM TASK 73-11-02-400-801).
(2) Install the IFPC (Ref. AMM TASK 73-11-01-400-801).
(3) Install the hydraulic pump (Ref. AMM TASK 29-11-51-400-805) and (Ref. AMM TASK 29-13-51-400-806).
(4) Examine the assembly for foreign objects, damage, and correct assembly.

5. Close-up
Subtask 72-61-01-410-068-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 the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-410-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL 462AR

Subtask 72-61-01-440-056-A ** ON A/C NOT FOR ALL

B. Do the reactivation of the thrust reverser system after ground maintenance (Ref. AMM TASK 78-30-00-440-805).

Subtask 72-61-01-410-069-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR
(2) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:50:12 UTC