Depressurize the Brake System

TASK 29-10-00-864-004-A
Depressurize the Brake System

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE LANDING GEAR. THIS WILL PREVENT UNWANTED MOVEMENT OF THE LANDING GEAR, AND THUS POSSIBLE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

1. Reason for the Job
To make sure that the brake system is depressurized before you work on it.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	2	WARNING NOTICE(S)

B. Referenced Information

REFERENCE	DESIGNATION
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
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 29-23-00-860-001-A	Disconnection of the Isolation Coupling of the Power Transfer Unit (PTU)
TASK 29-23-00-860-002-A	Connection of the Isolation Coupling of the Power Transfer Unit (PTU)
TASK 32-12-00-010-001-A	Open the Main Gear Doors for Access
TASK 32-12-00-410-001-A	Close the Main Gear Doors after Access
TASK 32-44-11-200-001-A	Functional Check of Parking/Emergency Brake Accumulator by Reading the Charge Pressure on the Accumulator Gauge
Depressurization Pushbutton of the Brake Relief Valve (3067GM)

3. Job Set-up
Subtask 29-10-00-010-073-A

A. Open the right main gear door (Ref. AMM TASK 32-12-00-010-001).

Subtask 29-10-00-860-097-A

B. Aircraft Maintenance Configuration
(1) Put the WARNING NOTICE(S) in position to tell persons not to pressurize the Yellow hydraulic system:

In the cockpit on the hydraulic section 40VU of the overhead panel,
On the ground service panel of the Yellow hydraulic system.

(2) Make sure that the Yellow hydraulic system is depressurized and put it in the maintenance configuration (Ref. AMM TASK 29-00-00-864-001).
(3) Depressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-001).
(4) Disconnect the isolation coupling of the Power Transfer Unit (PTU) (Ref. AMM TASK 29-23-00-860-001).

Subtask 29-10-00-865-080-A

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N30
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N31
** ON A/C ALL
123VU	Y HYD/ELEC/PUMP	3802GX	AB06
123VU	Y HYD/ELEC/ELEC PUMP/NORM	3801GX	AB03

4. Procedure
Subtask 29-10-00-864-053-A ** ON A/C NOT FOR ALL

A. Depressurization

(1) On the brake manifold (3016GM):

Operate the pushbutton of the brake relief valve (3067GM) to release the pressure in the brake system.

(2) On the gage (2585GM) of the brake accumulator (2582GM):

Make sure that the pressure decreases to the nitrogen fill pressure (Ref. AMM TASK 32-44-11-200-001).

Subtask 29-10-00-864-053-B ** ON A/C NOT FOR ALL

A. Depressurization

(1) Set the Anti-skid and Nose Wheel switch to OFF.
(2) Operate the pushbutton of the brake relief valve (3067GM) to release the pressure in the brake system.
(3) On the gage (2585GM) of the brake accumulator (2582GM):

Make sure that the pressure decreases to the nitrogen fill pressure (Ref. AMM TASK 32-44-11-200-001).

5. Close-up
Subtask 29-10-00-860-098-A

A. Put the aircraft back to its initial configuration.
(1) Connect the isolation coupling of the Power Transfer Unit (PTU) (Ref. AMM TASK 29-23-00-860-002).
(2) Pressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(3) Remove the WARNING NOTICE(S).

Subtask 29-10-00-865-081-A

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N30
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N31
** ON A/C ALL
123VU	Y HYD/ELEC/PUMP	3802GX	AB06
123VU	Y HYD/ELEC/ELEC PUMP/NORM	3801GX	AB03

Subtask 29-10-00-410-073-A

C. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the right main gear door (Ref. AMM TASK 32-12-00-410-001).

[Rev.10 from 2021] 2026.04.01 00:13:41 UTC