Electrical or hydraulic failure of the Normal Brake Servovalve 18GG.

TASK 32-42-00-810-808-A
Electrical or hydraulic failure of the Normal Brake Servovalve 18GG.

1. Possible Causes

SERVOVALVE-NORM BRK, WHEEL 4 [18GG]
PRESS XDCR-NORM BRK WHEEL 4 [14GG]
BSCU [10GG]
wiring from the BSCU (10GG) to the wheel 4- norm brake servovalve (18GG)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 32-42-00-810-958-A	Intermittent Electrical Failure of Normal Brake Servovalves 16GG & 18GG
ASM 324202
AMM 32-42-21-000-001	Removal of the Normal-Brake Pressure Transducer
AMM 32-42-21-400-001	Installation of the Normal-Brake Pressure Transducer
AMM 32-42-34-000-001	Removal of the Braking/Steering Control Unit (BSCU)
AMM 32-42-34-400-001	Installation of the Braking/Steering Control Unit (BSCU)
AMM 32-42-48-000-001	Removal of the Normal Brake Servovalve
AMM 32-42-48-400-001	Installation of the Normal Brake Servovalve
AMM 32-46-00-740-005	BITE Test of BSCU - Normal Braking TEST
TSM TASK 32-42-00-03	NORMAL BRAKING - TASK SUPPORTING DATA

3. Fault Confirmation
Subtask 32-42-00-700-060-B

A. Test

NOTE: If the BRAKES CH/SYS X FAULT ECAM warning was shown:

with one or more CFDS fault messages related to the Normal brake servovalves, and
during a landing gear free-fall extension, with these conditions only, you can ignore the ECAM warning.

(1) Do the BITE test of the Normal Braking System. AMM 32-46-00-740-005
(2) Read the TROUBLE SHOOTING DATA of the BSCU on the MCDU. 32-42-00-03 TSM TASK 32-42-00-03

4. Fault Isolation
Subtask 32-42-00-810-059-C

A. If the test gives the maintenance message BRK NORM SERVOVLV4 (18GG) and the TROUBLE SHOOTING DATA gives one of these fault codes: 44 or 52 or 513 or 523.

replace the SERVOVALVE-NORM BRK, WHEEL 4 [18GG] , AMM 32-42-48-000-001 and AMM 32-42-48-400-001.

(1) If the fault continues:

replace the PRESS XDCR-NORM BRK WHEEL 4 [14GG] AMM 32-42-21-000-001 and AMM 32-42-21-400-001.

Subtask 32-42-00-810-213-C

B. If the test gives the maintenance message BRK NORM SERVOVLV4 (18GG) and the TROUBLE SHOOTING DATA gives one of these fault codes: 28 or 36 or 88.

do a continuity /resistance test at the servovalve.

NOTE: The resistance must be between:

90 and 100 ohms for P/N C20XXXXXX between the terminals A and C, (E and F) for coil B1, (B2).
45 and 50 ohms for P/N E21XXXXXX between the terminals A and C, (A and F) for coil B1, (B2).

(1) If the test is not OK:

replace the SERVOVALVE-NORM BRK, WHEEL 4 [18GG] AMM 32-42-48-000-001 AMM 32-42-48-400-001

(2) If the test is OK:

replace the BSCU [10GG] . AMM 32-42-34-000-001 AMM 32-42-34-400-001

(a) If the fault continues:
For P/N C20XXXXXX:

if the source of the message is BSCU 1,do a check and repair the wiring from the BSCU (10GG) to the wheel 4- norm brake servovalve (18GG) pins AB/12K, 12J to pins A/C, A. ASM 324202
if the source of the message is BSCU 2, do a check and repair the wiring from the BSCU (10GG) to the wheel 4- norm brake servovalve (18GG) pins AB/12A, 12B to pins A/F, E. ASM 324202
For P/N E21XXXXXX:
if the source of the message is BSCU 1,do a check and repair the wiring from the BSCU (10GG) to the wheel 4- norm brake servovalve (18GG) pins AB/12K, 12J to pins A/C, A. ASM 324202
if the source of the message is BSCU 2, do a check and repair the wiring from the BSCU (10GG) to the wheel 4- norm brake servovalve (18GG) pins AB/12A, 12J to pins A/F, A. ASM 324202

Subtask 32-42-00-700-061-B ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.A.

NOTE: If there are intermittent faults on the normal brake servovalves 16GG and 18GG, you must do the trouble shooting task (Ref. TSM TASK 32-42-00-810-958).

[Rev.8 from Aug 2018] 2026.04.04 04:31:31 UTC