Functional Check of Brake Heat Pack for Wear by Use of the Wear Indicator (Parking Brake Applied)

TASK 32-42-27-210-003-A
Functional Check of Brake Heat Pack for Wear by Use of the Wear Indicator (Parking Brake Applied)

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

WARNING: LET THE BRAKES AND THE WHEELS BECOME COOL BEFORE YOU GO NEAR THE LANDING GEAR. DO NOT APPLY A LIQUID OR GAS DIRECTLY ON A HOT WHEEL OR BRAKE UNIT. THIS CAN CAUSE A TIRE EXPLOSION AND/OR A WHEEL RIM BURST.

ZONE: 731
ZONE: 741

1. Reason for the Job
Refer to the MPD TASK: 324227-01
FUNCTIONAL CHECK OF BRAKE HEAT PACK FOR WEAR BY USE OF THE WEAR INDICATOR (PARKING BRAKE APPLIED)
To do an inspection of the brake unit to make sure that the disc pads are not worn.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
731	L.H MAIN GEAR
741	R.H MAIN GEAR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 29-10-00-863-002-A	Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System
TASK 29-24-00-863-001-A	Pressurize the Yellow Hydraulic System with the Electric Pump
TASK 32-42-00-040-003-A	Deactivation of the Main Wheel Brakes
TASK 32-42-27-000-001-A	Removal of the Brake
TASK 32-42-27-400-001-A	Installation of the Brake
TASK 32-42-00-040-003-A	Deactivation of the Main Wheel Brakes (for corrective action)
TASK 32-42-27-000-001-A	Removal of the Brake (for corrective action)
TASK 32-42-27-400-001-A	Installation of the Brake (for corrective action)
Brake Unit-Wear Indicator ** ON A/C NOT FOR ALL
Brake Unit-Wear Indicator ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 32-42-27-860-055-A

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) In the cockpit, on triple indicator 60GG on the right center instrument-panel 400VU, make sure that the brake yellow pressure indicator is pressurized (the indicator pointer is in the green range).If necessary pressurize the brake accumulator:
(a) Pressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002) or (Ref. AMM TASK 29-24-00-863-001).
(b) On triple indicator 60GG on the right center instrument-panel 400VU, make sure that the pressure increase (the indicator pointer is in the green range)
(c) Depressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002).

Subtask 32-42-27-941-056-A

B. Safety Precautions
(1) Make sure that the wheel chocks are in position.
(2) Put the WARNING NOTICE(S) in the cockpit to tell persons not to operate the landing gear or the wheel brakes.
(3) On parking brake panel 110VU, put parking brake control-switch 73GG in the ON position.

Subtask 32-42-27-865-053-A

C. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	L/G/Y BRK/PRESS/IND	61GG	C10
** ON A/C NOT FOR ALL
49VU	ABCU &/Y BRK/PRESS IND	61GG	C10
** ON A/C ALL
121VU	HYDRAULIC/PARK BRK/CTL/STBY	71GG	N37
121VU	HYDRAULIC/PARK BRK/CTL/NORM	70GG	N36

4. Procedure
Subtask 32-42-27-210-056-E ** ON A/C NOT FOR ALL

A. Inspection of the Brake
(1) With the parking brake on, make sure that the wear indicators are in the limits.

NOTE: It is possible to measure the wear pin length at all brake temperatures when it is more than 1 mm (0.04 in.). When the length is 1 mm (0.04 in.) or less, we recommend that you do the check when the brake is cold (brake temperature less than 60 deg.C (140.00 deg.F)). This will give a more accurate measurement and prevent the removal or the deactivation of a serviceable brake unit.

(a) If the heat pack is fully worn, replace the related brake (Ref. AMM TASK 32-42-27-000-001) (Ref. AMM TASK 32-42-27-400-001).

NOTE: When the end of one of the two wear pins touch the machined surface of the piston housing, then the heat pack is fully worn.

(b) The brake units usually have two wear pins.
If you find a brake unit that does not have the two wear pins:
1 One wear pin is missing:

The brake is serviceable if the remaining wear pin is in the limits.

2 The two wear pins are missing:

Do the deactivation of the brake (Ref. AMM TASK 32-42-00-040-003).

(2) For a replacement brake:

Measure the distance between the end of the wear pin and the machined surface of the piston housing.

(a) If the replacement brake is not installed with the life extension shim, make sure that the distance between the:

End of the wear pin and the machined surface of the piston housing is between 49.6 mm (1.95 in.) and 50.4 mm (1.98 in.).

1 If the measured distance is not in the limits:

Replace the applicable brake (Ref. AMM TASK 32-42-27-000-001) (Ref. AMM TASK 32-42-27-400-001).

NOTE: If the replacement brake is installed with the life extension shim, the distance between the:

End of the wear pin and the machined surface of the piston housing will be less than 49.6 mm (1.95 in.).

(3) For the subsequent flights, make sure that the brake heat packs keep sufficient wear range in line with the operator's specified wear rate. This will keep the wear pin length more than the limit until the next scheduled wear check.

NOTE: To make an estimate for the next inspection, a wear rate of 1 mm (0.04 in.) for each 20 FC can be used.

Subtask 32-42-27-210-056-I ** ON A/C NOT FOR ALL

A. Inspection of the Brake
(1) With the parking brake on, make sure that the wear indicators are in the limits.

(a) When the end of one of the two wear pins touch the machined surface of the piston housing, the heat pack is fully worn. Replace the brake (Ref. AMM TASK 32-42-27-000-001) (Ref. AMM TASK 32-42-27-400-001).
(b) For a new brake, measure distance D between the end of the wear pin and the machined surface of the piston housing.
1 Make sure that distance D is between 60.2 mm (2.37 in.) and 61.8 mm (2.43 in.).
a If the distance is not in the limits or more than the maximum value:

Replace the brake (Ref. AMM TASK 32-42-27-000-001) (Ref. AMM TASK 32-42-27-400-001).

(c) The brake units usually have two wear pins.
If you find a brake unit that does not have the two wear pins:
1 One wear pin is missing:

The brake is serviceable if the remaining wear pin is in the limits.

2 The two wear pins are missing:

Do the deactivation of the related main wheel brake (Ref. AMM TASK 32-42-00-040-003).

(2) For the subsequent flights, make sure that the brake heat packs keep sufficient wear range in line with the operator's specified wear rate. This will keep the wear pin length more than the limit until the next scheduled wear check.

NOTE: To make an estimate for the next inspection, a wear rate of 1 mm (0.04 in.) for each 20 FC can be used.

Subtask 32-42-27-210-056-O ** ON A/C NOT FOR ALL

A. Inspection of the Brake
(1) With the parking brake on, make sure that the wear indicators are in the limits.

NOTE: It is possible to measure the wear pin length at all brake temperatures when it is more than 1 mm (0.04 in.). When the length is 1 mm (0.04 in.) or less, we recommend that you do the check when the brake is cold (brake temperature less than 60 deg.C (140.00 deg.F). This will give a more accurate measurement and prevent the removal or the deactivation of a serviceable brake unit.

(a) If the heat pack is fully worn, replace the related brake (Ref. AMM TASK 32-42-27-000-001) and (Ref. AMM TASK 32-42-27-400-001).

NOTE: When the end of one of the two wear pins touch the machined surface of the piston housing, then the heat pack is fully worn.

(b) Measure distance D between the end of the wear pin and the machined surface of the piston housing.
1 For the new brake or the replacement brake installed with the new heat pack:

Make sure that distance D is between 49.6 MM (1.9528 IN.) and 50.4 MM (1.9843 IN.).

2 For the replacement brake part numbers C20225508, C20225509 and C20225510:
a If the heat pack is not fully worn and installed with or without the life extension shim:

Make sure that distance D is less than 49.6 MM (1.9528 IN.).

3 If the measured distance is not in the limits:

Replace the applicable brake (Ref. AMM TASK 32-42-27-000-001) and (Ref. AMM TASK 32-42-27-400-001).

(c) The brake units usually have two wear pins. If you find a brake unit that does not have the two wear pins:
1 If one wear pin is missing:

The brake is serviceable if the remaining wear pin is in the limits.

2 If the two wear pins are missing:

Do the deactivation of the related main wheel brake (Ref. AMM TASK 32-42-00-040-003).

(2) For the subsequent flights, make sure that the brake heat packs keep sufficient wear range in line with the operator's specified wear rate.

NOTE: This will keep the wear pin length more than the limit until the next scheduled wear check.

NOTE: To make an estimate for the next inspection, a wear rate of 1 mm (0.04 in.) for each 20FC can be used.

5. Close-up
Subtask 32-42-27-941-057-A

A. Removal of Equipment
(1) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(2) Remove the WARNING NOTICE(S).
(3) Make sure that the work area is clean and clear of tools and other items.

Subtask 32-42-27-860-056-A

B. Put the aircraft back to its initial configuration.
(1) De-energize the Ground Service Network Supplied from the External Power (Ref. AMM TASK 24-42-00-862-001)

[Rev.10 from 2021] 2026.04.01 12:31:54 UTC