W DOC AIRBUS | TSM A320F

Loss of the Brake-Accumulator Pressure with Parking Brake Set to off

TASK 32-44-00-810-808-A
Loss of the Brake-Accumulator Pressure with Parking Brake Set to off

1. Possible Causes
  • CTL VALVE-PARK BRK,ELEC. [72GG]
  • BRAKE RELIEF VALVE [3067GM]
  • DUAL VALVE-ALTN BRK DISTR [2577GM]
  • AUTOMATIC SEL-BRK [2576GM]
  • ACCU-BRK YELLOW PRESS [2582GM]
  • CHECK VALVE Y [3058GM]
  • MANIFOLD [3016GM]
  • CTL VALVE-PARK BRK, ELEC [102GG]
  • SEL VALVE-ALTN BRK [99GG]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 12-14-32-614-002
Nitrogen Filling of the Yellow Hydraulic System, Brake Pressure Accumulator
AMM 29-14-00-614-001
Depressurization of the Hydraulic Reservoirs
AMM 29-14-00-614-002
Pressurization of the Hydraulic Reservoirs through the Ground Connector
AMM 32-42-13-000-001
Removal of the Automatic Selector
AMM 32-42-13-400-001
Installation of the Automatic Selector
AMM 32-43-14-000-001
Removal of the Dual-Valve Alternate Brake-Distribution
AMM 32-43-14-400-001
Installation of the Dual-Valve Alternate Brake-Distribution
AMM 32-43-51-000-001
Removal of the Alternate Braking Selector Valve
AMM 32-43-51-400-001
Installation of the Alternate Braking Selector Valve
AMM 32-44-00-720-002
Functional Check of Brake Accumulator System
AMM 32-44-11-000-001
Removal of the Accumulator
AMM 32-44-11-200-001
Functional Check of Parking/Emergency Brake Accumulator by Reading the Charge Pressure on the Accumulator Gauge
AMM 32-44-11-400-001
Installation of the Accumulator
AMM 32-44-15-000-001
Removal of the Pressure Relief Valve
AMM 32-44-15-400-001
Installation of the Pressure Relief Valve
AMM 32-44-17-000-001
Removal of the Brake Manifold
AMM 32-44-17-400-001
Installation of the Brake Manifold
AMM 32-45-51-000-001
Removal of the Parking-Brake Electrical Control-Valve
AMM 32-45-51-400-001
Installation of the Parking-Brake Electrical Control-Valve
AMM 32-45-53-000-001
Removal of the Parking-Brake Electrical Control-Valve
AMM 32-45-53-400-001
Installation of the Parking-Brake Electrical Control-Valve
F Alternate Brake System with Parking Brake set to Off ** ON A/C NOT FOR ALL
F Alternate Brake System with Parking Brake set to Off ** ON A/C NOT FOR ALL
3. Fault Confirmation
Subtask 32-44-00-720-050-A
A. Test
   (1) Do the functional test of the brake accumulator system AMM 32-44-00-720-002.
4. Fault Isolation
NOTE: : After all maintenance operations on the braking system such as hydraulic line disconnection/connection or component replacement, bleed from the brake units (Ref. AMM TASK 32-43-00-870-002).
NOTE: After disconnection of the hydraulic lines, it is important that you let the hydraulic pressure and leakage become stable (5 minutes minimum) before you make an estimate of component leakage.
Subtask 32-44-00-810-059-A ** ON A/C NOT FOR ALL
A. If the test confirms the fault:
F Alternate Brake System with Parking Brake set to Off ** ON A/C NOT FOR ALL
   (1) Do a check for leakage of the parking brake control valve (72GG):
  • on the Yellow brake-system relief-valve (3067GM) operate the manual depressurization pushbutton to release the accumulator pressure.
  • on the Yellow hydraulic system, depressurize the Yellow hydraulic reservoir AMM 29-14-00-614-001.
  • on the accumulator pressure gage (2585GM) make sure that nitrogen pressure is correct AMM 32-44-11-200-001.
  • on the automatic selector (2576GM) at port H (at the T level), disconnect the hydraulic line from the parking brake control valve (72GG).
  • install a plug on the T fitting.
  • on the Yellow hydraulic system, pressurize the Yellow hydraulic reservoir AMM 29-14-00-614-002.
  • use the Yellow electric pump to pressurize the Yellow brake accumulator (2582GM) to 206 bars (2988 psi) and stop the pump.
  • do a check for hydraulic leakage of the parking brake control valve (72GG).
     (a) If leakage is more than 20 drops/min:
     (b) If leakage is in the permitted tolerances:
  • operate the manual depressurization pushbutton of the relief valve (3067GM) to release the accumulator pressure.
  • on the Yellow hydraulic system, depressurize the Yellow hydraulic reservoir AMM 29-14-00-614-001.
  • connect the line on the T fitting.
   (2) Do a check for leakage of the relief valve (3067GM):
On the brake manifold (3016GM) disconnect the lines at ports D, E, F and G. Install a plug at ports E, F and G and a plug on the disconnected hydraulic lines.
  • on the Yellow hydraulic system, pressurize the Yellow hydraulic reservoir AMM 29-14-00-614-002.
  • use the Yellow electric pump to pressurize the Yellow brake accumulator (2582GM) to 206 bars (2988 psi) and stop the pump.
  • on the brake manifold (3016GM) do a check for hydraulic leakage at port D.
     (a) If leakage is more than 10 drops/min:
     (b) If leakage is in the permitted tolerances:
  • operate the manual depressurization pushbutton of the relief valve (3067GM) to release the accumulator pressure.
  • on the Yellow hydraulic system, depressurize the Yellow hydraulic reservoir AMM 29-14-00-614-001.
  • connect the line at port D.
   (3) Do a check for leakage of the Alternate-brake distribution dual-valve (2577GM):
  • on the brake manifold (3016GM) remove the caps and connect the lines at ports E, F and G.
  • on the brake distribution dual-valve (2577GM) disconnect the line at port B and install a plug on the disconnected hydraulic line.
  • use the Yellow electric pump to pressurize the Yellow brake accumulator (2582GM) to 206 bars (2988 psi) and stop the pump. In the cockpit, make sure that the PARKING BRK control switch is at OFF.
  • on the brake distribution dual-valve (2577GM) do a check for leakage at port B.
     (a) if leakage is more than:

-------------------------------------------------
! Tamb ! Limit !
-------------------------------------------------
! 70 >Tamb> 60 deg.c ! 102 cm3/mn !
!(158 >Tamb > 140 deg.F) ! ( 6.22 in.3/mn) !
!------------------------!----------------------!
! 60 >Tamb> 40 deg.C ! 80 cm3/mn !
!(140 >Tamb> 104 deg.F) ! (4.88 in.3/mn) !
!------------------------!----------------------!
! 40 >Tamb> 20 deg.C ! 50 cm3/mn !
!(104 >Tamb > 68 deg.F) ! (3.05 in.3/mn) !
!------------------------!----------------------!
! 20 >Tamb> 0 deg.C ! 30 cm3/mn !
!(68 >Tamb> 32 deg.F) ! (1.83 in.3/mn) !
!------------------------!----------------------!
! 0 >Tamb> -10 deg.C ! 14.4 cm3/mn !
! (32 >Tamb> 14 deg.F) ! (0.88 in.3/mn) !
!------------------------!----------------------!
! -10 >Tamb> -40 deg.C ! 10 cm3/mn !
! (14 >Tamb> -40 deg.F) ! (0.61 in.3/mn) !
-------------------------------------------------

     (b) If leakage is in the permitted tolerances:
  • operate the manual depressurization pushbutton of the relief valve (3067GM) to release the accumulator pressure.
  • on the Yellow hydraulic system, depressurize the Yellow hydraulic reservoir AMM 29-14-00-614-001.
  • connect the line at port B.
   (4) Do a check of the automatic selector (2576GM):
  • on the automatic selector (2576GM) disconnect the line at port H and install a plug on the disconnected hydraulic line.
  • on the Yellow hydraulic system, pressurize the Yellow hydraulic reservoir AMM 29-14-00-614-002.
  • use the Yellow electric pump to pressurize the Yellow brake accumulator (2582GM) to 206 bars (2988 PSI) and stop the pump.
  • on the automatic selector (2576GM) do a check for leakage at port H.
     (a) If leakage is more than 60 drops/min:
     (b) If leakage is in the permitted tolerances:
  • operate the manual depressurisation pushbutton of the relief valve (3067GM) to release the accumulator pressure.
  • on the Yellow hydraulic system, depressurize the Yellow hydraulic reservoir AMM 29-14-00-614-001.
  • connect the line at port H.
   (5) Do a check of the Yellow brake accumulator (2582GM)
  • on the brake accumulator (2582GM) release the nitrogen pressure.
  • remove the ACCU-BRK YELLOW PRESS [2582GM] AMM 32-44-11-000-001.
  • in the accumulator, on the nitrogen side, do a check for hydraulic fluid.
     (a) If there is hydraulic fluid:
     (b) If there is no hydraulic fluid:
   (6) Do a check of the parking brake manifold (3016GM):
  • inflate the accumulator with nitrogen AMM 12-14-32-614-002.
  • on the Yellow hydraulic system, pressurize the Yellow hydraulic reservoir AMM 29-14-00-614-002.
  • use the Yellow electric pump to pressurize the Yellow brake accumulator (2582GM) to 206 bars (2988 psi) and stop the pump.
     (a) If the fault continues:
Subtask 32-44-00-810-059-B ** ON A/C NOT FOR ALL
A. If the test confirms the fault:
F Alternate Brake System with Parking Brake set to Off ** ON A/C NOT FOR ALL
   (1) Do a check for leakage of the parking-brake control valve (102GG):
  • On the Yellow brake-system relief-valve (3067GM) operate the manual depressurization pushbutton to release the accumulator pressure.
  • On the Yellow hydraulic system, depressurize the hydraulic reservoir AMM 29-14-00-614-001.
  • On the accumulator pressure gage (2585GM) make sure that nitrogen pressure is correct AMM 32-44-11-200-001.
  • On the YELLOW ALT BRAKE SELECTOR VALVE MANIFOLD (3016GM) at port D (at the T level and on the parking brake control valve 102GG side), disconnect the hydraulic line from the parking-brake control valve (102GG).
  • Install a plug on the T fitting.
  • On the Yellow hydraulic system, pressurize the hydraulic reservoir AMM 29-14-00-614-002.
  • Use the Yellow electric pump to pressurize the Yellow brake accumulator (2582GM) to 206 bar (2988 psi) and stop the pump.
  • Do a check for hydraulic leakage of the parking-brake control valve (102GG).
     (a) If the leakage is more than 1 cm3/min:
     (b) If leakage is in the permitted tolerances:
  • Operate the manual depressurization pushbutton of the relief-valve (3067GM) to release the accumulator pressure.
  • Remove the plug on the T fitting.
  • Connect the line on the T fitting.
   (2) On the Yellow hydraulic system, pressurize the hydraulic reservoir AMM 29-14-00-614-002.
  • Use the Yellow electric pump to pressurize the Yellow-pressure brake accumulator (2582GM) to 206 bar (2988 psi) and stop the pump.
   (3) If the fault continues:
   (4) On the Yellow hydraulic system, pressurize the hydraulic reservoir AMM 29-14-00-614-002.
  • Use the Yellow electric pump to pressurize the Yellow-pressure brake accumulator (2582GM) to 206 bar (2988 psi) and stop the pump.
   (5) If the fault continues:
   (6) On the Yellow hydraulic system, pressurize the hydraulic reservoir AMM 29-14-00-614-002.
  • Use the Yellow electric pump to pressurize the Yellow-pressure brake accumulator (2582GM) to 206 bar (2988 psi) and stop the pump.
   (7) If the fault continues, do a check of the Yellow-pressure brake accumulator (2582GM):
  • Operate the manual depressurization pushbutton of the relief-valve (3067GM) to release the accumulator pressure.
  • On the Yellow hydraulic system, depressurize the hydraulic reservoir AMM 29-14-00-614-001.
  • On the Yellow-pressure brake accumulator (2582GM) release the nitrogen pressure.
  • Remove the Yellow-pressure brake accumulator (2582GM) AMM 32-44-11-000-001.
  • In the accumulator, on the nitrogen side, do a check for hydraulic fluid.
     (a) If there is hydraulic fluid:
  • Collect and measure the volume of the hydraulic fluid
       1 If the volume of the hydraulic fluid is more than 100 cm3 (6.10 in.3):
     (b) If there is no hydraulic fluid or if the volume of the hydraulic fluid is less than 100 cm3 (6.10 in.3):
  • Replace the CHECK VALVE Y [3058GM] .
  • Install the Yellow-pressure brake accumulator (2582GM) AMM 32-44-11-400-001.
  • Inflate the accumulator with nitrogen AMM 12-14-32-614-002.
  • On the Yellow hydraulic system, pressurize the hydraulic reservoir AMM 29-14-00-614-002.
  • Use the Yellow electric pump to pressurize the Yellow-pressure brake accumulator (2582GM) to 206 bar (2988 psi) and stop the pump.
   (8) If the fault continues:
[Rev.8 from Aug 2018] 2026.04.04 04:31:43 UTC
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