Installation of the Hydraulic Low-Pressure Switch Tube
TASK 29-13-49-400-005-A
Installation of the Hydraulic Low-Pressure Switch Tube
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 29-13-49-860-078-A ** ON A/C NOT FOR ALL
Subtask 29-13-49-420-058-A ** ON A/C NOT FOR ALL
Subtask 29-13-49-410-066-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 00:22:35 UTC
Installation of the Hydraulic Low-Pressure Switch Tube
WARNING:
OBEY THE HYDRAULIC SAFETY PROCEDURES.
WARNING:
DO NOT TOUCH THE HYDRAULIC SYSTEM COMPONENTS FOR A SHORT TIME AFTER THE ENGINE IS SHUTDOWN. THE ENGINE COMPONENTS STAY HOT FOR SOME TIME AND CAN CAUSE INJURY.
CAUTION:
DO NOT LET HYDRAULIC FLUID FALL ON THE ENGINE. UNWANTED HYDRAULIC FLUID MUST BE REMOVED IMMEDIATELY WITH A CLEAN LINT FREE CLOTH. THE FLUID CAN CAUSE DAMAGE TO THE SURFACE PROTECTION AND TO SOME PARTS.
1. Reason for the JobSelf explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 195BB | |
| FOR [1000EM2] (ENGINE-2) | |
| 447AL | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 12-12-29-611-001-A | Fill the Hydraulic Fluid Reservoir with a Hand Pump |
| TASK 12-12-29-611-002-A | Fill the Hydraulic Fluid Reservoir with a Hydraulic Service Cart |
| TASK 29-10-00-864-002-A | Depressurize the Yellow Hydraulic System |
| TASK 29-13-00-710-002-A | Operational Test of the Yellow Hydraulic System |
| TASK 29-14-00-614-001-A | Depressurization of the Hydraulic Reservoirs |
| TASK 29-14-00-614-002-A | Pressurization of the Hydraulic Reservoirs through the Ground Connector |
| TASK 29-14-00-614-002-A-01 | Pressurization of the Hydraulic Reservoirs with the Auxiliary Power Unit (APU) |
| TASK 71-13-00-410-040-B | Closing of the Fan Cowl Doors |
Subtask 29-13-49-860-078-A ** ON A/C NOT FOR ALL
A. Aircraft Maintenance Configuration
(1) Make sure that the Yellow hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-10-00-864-002)
(2) Make sure that the Yellow hydraulic reservoir is depressurized (Ref. AMM TASK 29-14-00-614-001).
(3) Make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to pressurize the Yellow hydraulic system:
(5) Make sure that an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position at the engine 1(2).
(6) Make sure that the fan-cowl door 447AL is open.
Subtask 29-13-49-941-072-A ** ON A/C NOT FOR ALL (1) Make sure that the Yellow hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-10-00-864-002)
(2) Make sure that the Yellow hydraulic reservoir is depressurized (Ref. AMM TASK 29-14-00-614-001).
(3) Make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to pressurize the Yellow hydraulic system:
- on the ground service panel 198CB.
(5) Make sure that an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position at the engine 1(2).
(6) Make sure that the fan-cowl door 447AL is open.
B. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(3) Make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to pressurize the Yellow hydraulic system:
(6) Make sure that the CONTAINER 5 L (1.32 USGAL) is below the hydraulic low-pressure switch tube (15) to collect the remaining fluid.
Subtask 29-13-49-865-060-A ** ON A/C NOT FOR ALL (1) On the center pedestal, on the ENG panel 115VU:
- make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to start the engine.
(3) Make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to pressurize the Yellow hydraulic system:
- in the cockpit, on the HYD section of the overhead panel 40VU.
- make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(6) Make sure that the CONTAINER 5 L (1.32 USGAL) is below the hydraulic low-pressure switch tube (15) to collect the remaining fluid.
C. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:
4. Procedure| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | HYDRAULIC/Y HYD/PUMP ENG2/MONG | 3700GD | Q37 |
Subtask 29-13-49-420-058-A ** ON A/C NOT FOR ALL
A. Installation of the Hydraulic Low-Pressure Switch Tube
PRE SB RA32029-13
(1) Remove the COVER - PROTECTION from the hydraulic low-pressure switch tube (15), the fitting on the pressure hose/tube and the hydraulic low-pressure switch.
(2) Loosely connect the low-pressure switch tube (15) to the pressure hose/tube.
(3) Loosely connect the low-pressure switch tube (15) to the hydraulic low-pressure switch.
(4) Install the clamps (20), the wascher (10) and the bolt (5) that attaches the low-pressure tube (15) to the top case drain hose/tube and to the channel. Do not tighten the bolt at this time.
(5) Install the clamp (20), the wascher (10) and the bolt (5) that attaches the low-pressure switch tube (15) to the bracket on the channel. Do not tighten the bolt at this time.
(6) Make sure that the low-pressure switch tube (15) is in the correct position on the engine.
.
(8) TORQUE the coupling nut on the pressure hose/tube to between 2.76 and 2.42 m.daN (20.35 and 17.85 lbf.ft )
(9) Torque the bolts (5) as follows:
.
(b) TORQUE the bolt (5) that attach the low-pressure switch tube (15) to the bracket on the channel to between 0.39 and 0.34 m.daN (34.51 and 30.09 lbf.in )
.
END OF PRE SB RA32029-13
Subtask 29-13-49-420-109-A ** ON A/C NOT FOR ALL PRE SB RA32029-13
(1) Remove the COVER - PROTECTION from the hydraulic low-pressure switch tube (15), the fitting on the pressure hose/tube and the hydraulic low-pressure switch.
(2) Loosely connect the low-pressure switch tube (15) to the pressure hose/tube.
(3) Loosely connect the low-pressure switch tube (15) to the hydraulic low-pressure switch.
(4) Install the clamps (20), the wascher (10) and the bolt (5) that attaches the low-pressure tube (15) to the top case drain hose/tube and to the channel. Do not tighten the bolt at this time.
(5) Install the clamp (20), the wascher (10) and the bolt (5) that attaches the low-pressure switch tube (15) to the bracket on the channel. Do not tighten the bolt at this time.
(6) Make sure that the low-pressure switch tube (15) is in the correct position on the engine.
NOTE: Use a second WRENCH - STANDARD to hold the fittings when you tighten the coupling nuts. This prevents damage to the tube assemblies.
(7) TORQUE the coupling nut on the low-pressure switch (15) to between 405 and 380 lbf.in (4.58 and 4.29 m.daN )
. (8) TORQUE the coupling nut on the pressure hose/tube to between 2.76 and 2.42 m.daN (20.35 and 17.85 lbf.ft )

(9) Torque the bolts (5) as follows:
CAUTION:
YOU MUST TORQUE THE BOLTS IN THE SEQUENCE GIVEN. IF YOU DO NOT TORQUE THE BOLTS IN SEQUENCE, YOU CAN CAUSE DAMAGE TO THE LOW-PRESSURE SWITCH TUBE.
(a) TORQUE the bolt (5) that attaches the low-pressure switch tube (15) to the top case drain hose/tube and to the channel to between 0.39 and 0.34 m.daN (34.51 and 30.09 lbf.in )
. (b) TORQUE the bolt (5) that attach the low-pressure switch tube (15) to the bracket on the channel to between 0.39 and 0.34 m.daN (34.51 and 30.09 lbf.in )
. END OF PRE SB RA32029-13
B. Installation of the Hydraulic Low-Pressure Switch Tube
POST SB RA32029-13
(1) Remove the COVER - PROTECTION from the hydraulic low-pressure switch tube hose/tube assembly (17), the fitting on the pressure hose/tube and the hydraulic low-pressure switch.
(2) Loosely connect the low-pressure switch hose/tube assembly (17) to the pressure hose/tube.
(3) Loosely connect the low-pressure switch hose/tube assembly (17) to the hydraulic low-pressure switch.
(4) Install the clamp (20) on the low-pressure switch hose/tube assembly (17). Attach the low-pressure switch hose/tube assembly (17) to the channel with the bolt (7) and the washer (10). Do not tighten the bolt at this time.
(5) Install the clamps (20) on the low-pressure switch hose/tube assembly (17). Attach the low-pressure switch hose/tube assembly (17) to the channel with bolts (7), the washers (10) and the nuts (25). Do not tighten the bolts at this time.
(6) Make sure that the low-pressure switch hose/tube assembly (17) is in the correct position on the engine.
.
(8) TORQUE the coupling nut on the pressure hose/tube to between 20.35 and 17.85 lbf.ft (2.76 and 2.42 m.daN )
(9) Torque the bolts (7) as follows:
.
(b) TORQUE the bolts (7) on the top of the channel to between 34.51 and 30.09 lbf.in (0.39 and 0.34 m.daN )
.
END OF POST SB RA32029-13
Subtask 29-13-49-420-110-A ** ON A/C NOT FOR ALL POST SB RA32029-13
(1) Remove the COVER - PROTECTION from the hydraulic low-pressure switch tube hose/tube assembly (17), the fitting on the pressure hose/tube and the hydraulic low-pressure switch.
(2) Loosely connect the low-pressure switch hose/tube assembly (17) to the pressure hose/tube.
(3) Loosely connect the low-pressure switch hose/tube assembly (17) to the hydraulic low-pressure switch.
(4) Install the clamp (20) on the low-pressure switch hose/tube assembly (17). Attach the low-pressure switch hose/tube assembly (17) to the channel with the bolt (7) and the washer (10). Do not tighten the bolt at this time.
(5) Install the clamps (20) on the low-pressure switch hose/tube assembly (17). Attach the low-pressure switch hose/tube assembly (17) to the channel with bolts (7), the washers (10) and the nuts (25). Do not tighten the bolts at this time.
(6) Make sure that the low-pressure switch hose/tube assembly (17) is in the correct position on the engine.
NOTE: Use a second WRENCH - STANDARD to hold the fittings when you torque the coupling nuts. This prevents damage to the tube assemblies.
(7) TORQUE the coupling nut on the low-pressure switch to between 405 and 380 lbf.in (4.58 and 4.29 m.daN )
. (8) TORQUE the coupling nut on the pressure hose/tube to between 20.35 and 17.85 lbf.ft (2.76 and 2.42 m.daN )

(9) Torque the bolts (7) as follows:
CAUTION:
YOU MUST TORQUE THE BOLTS IN THE SEQUENCE GIVEN. IF YOU DO NOT TORQUE THE BOLTS IN SEQUENCE, YOU CAN CAUSE DAMAGE TO THE LOW-PRESSURE SWITCH HOSE/TUBE ASSEMBLY.
(a) TORQUE the bolt (7) on the side of the channel to between 34.51 and 30.09 lbf.in (0.39 and 0.34 m.daN )
. (b) TORQUE the bolts (7) on the top of the channel to between 34.51 and 30.09 lbf.in (0.39 and 0.34 m.daN )
. END OF POST SB RA32029-13
C. Installation of the Hydraulic Low-Pressure Switch Tube
POST SB RA32029-15
POST SB RA32029-16
(1) Remove the COVER - PROTECTION from the hydraulic low-pressure switch tube hose assembly (19), the fitting on the pressure hose/tube and the hydraulic low-pressure switch.
(2) Loosely connect the low-pressure switch hose assembly (19) to the pressure hose/tube.
(3) Loosely connect the low-pressure switch hose assembly (19) to the hydraulic low-pressure switch.
(4) Make sure that the low-pressure switch hose assembly (19) is in the correct position on the engine.
(5) TORQUE the end fitting of the low pressure switch hose assembly (19) on the pressure hose/tube union to between 245 and 215 lbf.in (2.77 and 2.43 m.daN )
.
.
END OF POST SB RA32029-15
END OF POST SB RA32029-16
Subtask 29-13-49-710-063-A ** ON A/C NOT FOR ALL POST SB RA32029-15
POST SB RA32029-16
(1) Remove the COVER - PROTECTION from the hydraulic low-pressure switch tube hose assembly (19), the fitting on the pressure hose/tube and the hydraulic low-pressure switch.
(2) Loosely connect the low-pressure switch hose assembly (19) to the pressure hose/tube.
(3) Loosely connect the low-pressure switch hose assembly (19) to the hydraulic low-pressure switch.
(4) Make sure that the low-pressure switch hose assembly (19) is in the correct position on the engine.
(5) TORQUE the end fitting of the low pressure switch hose assembly (19) on the pressure hose/tube union to between 245 and 215 lbf.in (2.77 and 2.43 m.daN )
. NOTE: Use a second WRENCH - STANDARD to hold the union when you torque the end fitting. This prevents damage to the pressure hose/tube.
(6) TORQUE the end fitting of the low pressure switch hose assembly (19) on the low-pressure switch adapter fitting union to between 315 and 300 lbf.in (3.56 and 3.39 m.daN )
. NOTE: Use a second WRENCH - STANDARD to hold the union when you torque the end fitting. This prevents damage to the adapter fitting.
END OF POST SB RA32029-15
END OF POST SB RA32029-16
D. Operational Test
(1) Pressurize the Yellow hydraulic reservoir (Ref. AMM TASK 29-14-00-614-002).
(2) Do an operational test of the Yellow hydraulic system (Ref. AMM TASK 29-13-00-710-002).
(3) During the dry motoring of the engine 2, make sure that there are no leaks from the hydraulic low-pressure switch tube.
(4) Make sure that the level of the hydraulic fluid in the Yellow reservoir is correct. If necessary, fill the reservoir (Ref. AMM TASK 12-12-29-611-001) or (Ref. AMM TASK 12-12-29-611-002).
5. Close-up(1) Pressurize the Yellow hydraulic reservoir (Ref. AMM TASK 29-14-00-614-002).
(2) Do an operational test of the Yellow hydraulic system (Ref. AMM TASK 29-13-00-710-002).
(3) During the dry motoring of the engine 2, make sure that there are no leaks from the hydraulic low-pressure switch tube.
(4) Make sure that the level of the hydraulic fluid in the Yellow reservoir is correct. If necessary, fill the reservoir (Ref. AMM TASK 12-12-29-611-001) or (Ref. AMM TASK 12-12-29-611-002).
Subtask 29-13-49-410-066-A ** ON A/C NOT FOR ALL
A. Close Access
(1) Remove the container.
(2) Remove the WARNING NOTICE(S).
(3) Remove the access platform(s).
(4) Make sure that the work area is clean and clear of tools and other items.
(5) Close the left fan-cowl door (Ref. AMM TASK 71-13-00-410-040):
(a) FOR [1000EM2] (ENGINE-2)
close the door 447AL.
(6) Close the door 195BB.
(1) Remove the container.
(2) Remove the WARNING NOTICE(S).
(3) Remove the access platform(s).
(4) Make sure that the work area is clean and clear of tools and other items.
(5) Close the left fan-cowl door (Ref. AMM TASK 71-13-00-410-040):
(a) FOR [1000EM2] (ENGINE-2)
close the door 447AL.
(6) Close the door 195BB.
Hydraulic Low-Pressure Switch Tube