DOC AIRBUS | AMM A320FRe-greasing of the Variable Bleed Valve (VBV) System [CFMB]
TASK 75-31-00-640-801-A
Re-greasing of the Variable Bleed Valve (VBV) System
To do a re-greasing of the VBV system and to decrease the actuation torque of the ballscrew actuators.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Referenced Information
3. Job Set-up
Subtask 75-31-00-941-071-A ** ON A/C NOT FOR ALL
Subtask 75-31-00-640-051-A ** ON A/C NOT FOR ALL
(2) Remove and keep the plug.
(3) Turn the VBV system as necessary, to align the grease fitting that is integrated on the translating nut of the bleed valve stop mechanism, which is directly below the open re-grease port.
(4) Do the steps that follow one time for each single use GUN - SEALANT / NEEDLE combination to be used in this maintenance procedure:
(a) Fill the GUN - SEALANT with Mobil 28 (MIL-PRF-81322).
(b) Prime the system to remove any air bubbles until each activation of the GUN - SEALANT gives a solid mass of grease.
(c) Eject thirty full activations of the GUN - SEALANT into a calibrated SCALE.
(d) Use a piece of PAPER - WAX or equivalent to catch the grease.
(e) Zero the scale with the tare before adding grease.
(f) Record the weight of grease given by thirty full activations of the GUN - SEALANT.
(g) Divide the total weight by thirty to find the average weight of grease ejected for each activation of the GUN - SEALANT.
(h) Record and save this quantity for reference.
(i) Do this procedure one time only for each single use GUN - SEALANT / NEEDLE combination used in this maintenance procedure.
(5) For each step below, find the number of GUN - SEALANT activations that are necessary to give the specified weight of grease. In all conditions, round up as necessary to find how many activations are necessary. For example, if Step (4)(g) above gives a calculation of 0.014 oz (0.40 g) of grease per activation, 0.018 oz (0.51 g) of grease must be applied at each step. Thus, the correct number of activations must be two, because one activation gives less than the necessary 0.018 oz (0.51 g).
(a) Insert the NEEDLE directly into the grease fitting on the translating nut of the stop mechanism. While you press down firmly, add 0.018 oz (0.51 g) of Mobil 28 (MIL-PRF-81322) into the grease fitting.
(b) Move the stop mechanism nut away from the re-grease port to the base until you get access to the outer bearing. In order to move the nut, operate the VBV system manually (Ref. AMM TASK 75-31-00-200-002).
(c) Tilt the NEEDLE into the re-grease port and apply 0.018 oz (0.51 g) of Mobil 28 (MIL-PRF-81322) to the bottom of the housing onto the bearing.
(d) Move the stop mechanism nut until it engages the outer nut stop/bearing.In order to move the nut, operate the VBV system manually (Ref. AMM TASK 75-31-00-200-002).
(e) Tilt the NEEDLE in the re-grease port and apply 0.04 oz (1.13 g) of Mobil 28 (MIL-PRF-81322) onto the top of the threaded tube and the anti-rotation pin.
(f) Tilt the NEEDLE down to the bottom of the housing below the threaded tube and add 0.14 oz (3.97 g) of Mobil 28 (MIL-PRF-81322) to the bottom of the stop mechanism housing.
(g) Re-install the plug and TORQUE to between 35 and 30 lbf.in (0.40 and 0.34 m.daN )
.
(h) Safety the plug with theCP8001 lockwire 0.032 in. (0.8 mm) dia.
Subtask 75-31-00-640-050-A ** ON A/C NOT FOR ALL
Subtask 75-31-00-410-086-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 03:10:27 UTC
Re-greasing of the Variable Bleed Valve (VBV) System
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
ZONE: 400
1. Reason for the JobTo do a re-greasing of the VBV system and to decrease the actuation torque of the ballscrew actuators.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE |
| No specific | 1 | GUN - SEALANT |
| No specific | 1 | MIRROR - INSPECTION |
| No specific | 1 | NEEDLE |
| No specific | 1 | PAPER - WAX |
| No specific | 1 | SCALE |
| No specific | AR | WARNING NOTICE(S) |
| No specific | Torque wrench: range to between 35 and 30 lbf.in (0.40 and 0.34 m.daN ) | |
| 79000494-1 | 1 | VBV SYSTEM GREASER |
| 856A2501 | 1 | WRENCH-VBV MANUAL CONTROL |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.CP1041) | isopropyl alcohol |
| (Material No.CP8001) | lockwire 0.032 in. (0.8 mm) dia. |
| (Material No.14SBA1) | Textile-Lint free Cotton - |
| No specific | Mobil 28 (MIL-PRF-81322) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| FOR [1000EM1] (ENGINE-1) | |
| 437AL, 438AR, 451AL, 452AR | |
| FOR [1000EM2] (ENGINE-2) | |
| 447AL, 448AR, 461AL, 462AR | |
| 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 72-23-00-000-027-A | Removal of the Fan Duct Panels |
| TASK 72-23-00-400-027-A | Installation of the Fan Duct Panels |
| TASK 75-31-00-200-002-A | Manual Operation Check of the Variable Bleed Valve Doors |
| TASK 75-31-00-820-001-A | Adjustment of the Reference CLOSED Position of the VBV System |
| TASK 75-31-70-400-002-A | Installation of the Variable Bleed Valve position Sensor |
| 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 78-36-00-010-040-B | Opening of the Thrust Reverser Doors |
| TASK 78-36-00-410-040-B | Closing of the Thrust Reverser Doors |
Removal of the Fan Duct PanelsSubtask 75-31-00-941-071-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(a) Put a WARNING NOTICE(S) in position to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than five 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) in position to tell persons not to energize the FADEC 1(2).
Subtask 75-31-00-010-092-A ** ON A/C NOT FOR ALL WARNING:
BEFORE YOU DO THESE TASKS, MAKE SURE THAT THE SAFETY PRECAUTIONS TO PREVENT INJURY TO PERSONS OR DAMAGE TO EQUIPMENT ARE OBEYED (REF. AMM TASK 75-31-00-820-001).
(1) On the center pedestal, on ENG panel 115VU: (a) Put a WARNING NOTICE(S) in position to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than five 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) in position to tell persons not to energize the FADEC 1(2).
B. 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 an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.
Subtask 75-31-00-040-066-A ** ON A/C NOT FOR ALL (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 an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.
C. Deactivation of the Thrust Reverser
Subtask 75-31-00-010-093-A ** ON A/C NOT FOR ALL WARNING:
MAKE THE THRUST REVERSER UNSERVICEABLE. IF THE THRUST REVERSER IS NOT MADE UNSERVICEABLE, IT CAN OPERATE ACCIDENTALLY BECAUSE THE BLOCKER DOOR HOLD-OPEN ROD DOES NOT RESIST THE ACTUATOR HYDRAULIC PRESSURE.
THIS CAN CAUSE INJURY TO PERSONNEL AND/OR DAMAGE TO EQUIPMENT.
(1) Make the thrust reverser unserviceable (Ref. AMM TASK 78-30-00-481-041). D. Open the thrust reverser doors (Ref. AMM TASK 78-36-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
4. Procedure(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
Subtask 75-31-00-640-051-A ** ON A/C NOT FOR ALL
WARNING:
USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.
CAUTION:
WHILE THE PLUG IS REMOVED, STORE IT:
A. Re-greasing of the Bleed Valve Stop Mechanism for POST CFM SB 75-0056 - WHERE IT WILL NOT FALL OR GET LOST
- IN A CLEAN PLACE. IF YOU DO NOT OBEY THESE INSTRUCTIONS, YOU CAN CAUSE FOREIGN OBJECT DAMAGE AND/OR CONTAMINATION OF THE PLUG.
NOTE: The PRE CFM SB 75-0056 bleed valve stop mechanisms do not have grease fittings.
(1) Carefully remove the lockwire from the plug. (2) Remove and keep the plug.
(3) Turn the VBV system as necessary, to align the grease fitting that is integrated on the translating nut of the bleed valve stop mechanism, which is directly below the open re-grease port.
(4) Do the steps that follow one time for each single use GUN - SEALANT / NEEDLE combination to be used in this maintenance procedure:
(a) Fill the GUN - SEALANT with Mobil 28 (MIL-PRF-81322).
(b) Prime the system to remove any air bubbles until each activation of the GUN - SEALANT gives a solid mass of grease.
(c) Eject thirty full activations of the GUN - SEALANT into a calibrated SCALE.
(d) Use a piece of PAPER - WAX or equivalent to catch the grease.
(e) Zero the scale with the tare before adding grease.
(f) Record the weight of grease given by thirty full activations of the GUN - SEALANT.
(g) Divide the total weight by thirty to find the average weight of grease ejected for each activation of the GUN - SEALANT.
(h) Record and save this quantity for reference.
(i) Do this procedure one time only for each single use GUN - SEALANT / NEEDLE combination used in this maintenance procedure.
(5) For each step below, find the number of GUN - SEALANT activations that are necessary to give the specified weight of grease. In all conditions, round up as necessary to find how many activations are necessary. For example, if Step (4)(g) above gives a calculation of 0.014 oz (0.40 g) of grease per activation, 0.018 oz (0.51 g) of grease must be applied at each step. Thus, the correct number of activations must be two, because one activation gives less than the necessary 0.018 oz (0.51 g).
(a) Insert the NEEDLE directly into the grease fitting on the translating nut of the stop mechanism. While you press down firmly, add 0.018 oz (0.51 g) of Mobil 28 (MIL-PRF-81322) into the grease fitting.
(b) Move the stop mechanism nut away from the re-grease port to the base until you get access to the outer bearing. In order to move the nut, operate the VBV system manually (Ref. AMM TASK 75-31-00-200-002).
(c) Tilt the NEEDLE into the re-grease port and apply 0.018 oz (0.51 g) of Mobil 28 (MIL-PRF-81322) to the bottom of the housing onto the bearing.
(d) Move the stop mechanism nut until it engages the outer nut stop/bearing.In order to move the nut, operate the VBV system manually (Ref. AMM TASK 75-31-00-200-002).
(e) Tilt the NEEDLE in the re-grease port and apply 0.04 oz (1.13 g) of Mobil 28 (MIL-PRF-81322) onto the top of the threaded tube and the anti-rotation pin.
(f) Tilt the NEEDLE down to the bottom of the housing below the threaded tube and add 0.14 oz (3.97 g) of Mobil 28 (MIL-PRF-81322) to the bottom of the stop mechanism housing.
(g) Re-install the plug and TORQUE to between 35 and 30 lbf.in (0.40 and 0.34 m.daN )
. (h) Safety the plug with the
B. Re-greasing of the Variable Bleed Valve (VBV) System
(1) Remove all the fan duct panels (Ref. AMM TASK 72-23-00-000-027).
(2) Close all the 12 VBV doors:
(a) Engage the 856A2501 WRENCH-VBV MANUAL CONTROL on the VBV actuator wrench adapter and rotate the wrench until all 12 VBV doors are fully closed.
(a) Remove the existing rigid rod or hose from the grease hand pump, if any.
(b) Attach the lubrication hose on the grease hand pump and install the 79000494-1 VBV SYSTEM GREASER on the other side of the hose.
Repeat this operation on all the VBV actuators.
(b) Engage the 856A2501 WRENCH-VBV MANUAL CONTROL again on the VBV actuator wrench adapter and operate it in the two directions (from full open to full closed).
Repeat this operation at least three times to distribute the grease inside each actuator.
(7) Check the VBV position sensor (Ref. AMM TASK 75-31-70-400-002).
(8) Install all the 12 fan duct panels (Ref. AMM TASK 72-23-00-400-027).
5. Close-up(1) Remove all the fan duct panels (Ref. AMM TASK 72-23-00-000-027).
(2) Close all the 12 VBV doors:
(a) Engage the 856A2501 WRENCH-VBV MANUAL CONTROL on the VBV actuator wrench adapter and rotate the wrench until all 12 VBV doors are fully closed.
NOTE: The VBV actuator wrench adapter is located at 3:30 o'clock.
(3) Preparation of the Mobil 28 grease hand pump: (a) Remove the existing rigid rod or hose from the grease hand pump, if any.
(b) Attach the lubrication hose on the grease hand pump and install the 79000494-1 VBV SYSTEM GREASER on the other side of the hose.
NOTE: Each side of the hose has a different thread. One thread attaches the pump body and the other attaches the nozzle.
(4) Locate the grease fitting hole of each VBV actuator and clean it properly with the isopropyl alcohol (Material No.CP1041) and with the Textile-Lint free Cotton - (Material No.14SBA1) . NOTE: Each VBV actuator has only one grease nozzle fitting, which is located adjacent to the identification plate.
NOTE: For VBV actuators located at 12:30 o'clock, you can use the MIRROR - INSPECTION to find the location of the grease fitting holes more easily.
(5) Re-greasing of the VBV actuators. NOTE: Two persons are required to do this task. While one person holds the hand pump nozzle tip against the grease nozzle fitting, the second person pumps the grease.
(a) Get access to VBV actuator at 1:30 o'clock and smoothly apply grease of approximately 0.1 oz (2.83 g) to 0.17 oz (4.82 g) to the grease nozzle fitting. Repeat this operation on all the VBV actuators.
(b) Engage the 856A2501 WRENCH-VBV MANUAL CONTROL again on the VBV actuator wrench adapter and operate it in the two directions (from full open to full closed).
Repeat this operation at least three times to distribute the grease inside each actuator.
NOTE: The VBV actuator wrench adapter is located at 3:30 o'clock.
(6) Make sure that the VBV ballscrew actuators are in the fully closed position (Ref. AMM TASK 75-31-00-820-001). (7) Check the VBV position sensor (Ref. AMM TASK 75-31-70-400-002).
(8) Install all the 12 fan duct panels (Ref. AMM TASK 72-23-00-400-027).
Subtask 75-31-00-410-086-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 doors (Ref. AMM TASK 78-36-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
Subtask 75-31-00-440-066-A ** ON A/C NOT FOR ALL Subtask 75-31-00-410-087-A ** ON A/C NOT FOR ALL (1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser doors (Ref. AMM TASK 78-36-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR.