(5)
Push the brake pedals fully seven times to release hydraulic pressure from the brake accumulator.
S 864-005
NOTE: Pause a minimum of 5 seconds between each brake application.
____
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Alternate-Brake Selector Valve Installation
Figure 401
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S 864-007
(6)
Open the circuit breaker and attach the DO-NOT-REMOVE tag:
(a)
P11, Overhead Circuit Breaker Panel
1) 11S13, BRAKE PRESS IND
S 024-008
(7)
Disconnect the electrical connector from the pressure switch.
S 024-009
(8)
Disconnect the hydraulic lines from the selector valve (Detail A), Cap lines.
S 024-010
(9)
Remove unions from ports of valve. Discard O-rings and backup rings. Plug ports.
S 024-011
(10)
Remove 3 bolts to remove the selector valve.
TASK 32-41-04-404-012
3. Install the Alternate Brake Selector Valve (Fig. 401)__________________________________________
A. Consumable Materials
(1)
D00153 Fluid - Hydraulic, BMS 3-11
(2)
D00054 Lubricant - Hydraulic System Fittings, MCS 352
B.
References
(1)
AMM 24-22-00/201, Electrical Powere - Control
(2)
AMM 29-11-00/201, Pressurize/Depressurize Main Hydraulic System
(3)
AMM 32-00-15/201, Landing Gear Door Locks
(4)
AMM 32-00-20/201, Landing Gear Downlocks
C.
Access
(1)
Location Zones
211 Control Cabin, Left
212 Control Cabin, Right
731 Landing Gear Left
741 Landing Gear Right
D.
Procedure
S 164-013
(1)
Clean the selector valve and the mating surfaces of the mounting bracket.
S 424-014
(2)
Install 3 bolts to attach the selector valve to the mounting bracket (Detail A).
S 644-015
(3)
Lightly apply hydraulic fluid or lubricant to the unions, backup rings, and O-rings.
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(4) S 424-016Install the unions in the valve ports.
(5) S 424-031Install new O-rings and backup rings on the valve unions.
(6) S 424-017Connect hydraulic lines to the valve.
(7) S 424-018Attach electrical connector to the valve.
(8) S 864-019Remove the DO-NOT-CLOSE tag and close the circuit breaker: (a) P11, Overhead Circuit Breaker Panel 1) 11S13, BRAKE PRESS IND
(9) S 864-020Supply electrical power (AMM 24-22-00/201).
S 864-021
(10)
Supply right and left systems hydraulic power (AMM 29-11-00/201).
S 874-022
(11)
Slowly push on the brake pedals fully six times to bleed the system.
NOTE: Pause a minimum of 5 seconds between each brake application.
____
S 714-023
(12)
Do an operational test on the alternate brake selector valve (right hydraulic system).
(a)
Apply and release brakes several times by depressing brake pedals.
(b)
Check brake stacks movement to verify that brake is operating properly.
S 714-024
(13)
Do an operation test on the alternate brake selector valve (left hydraulic system).
(a)
Remove right system hydraulic power.
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(b)
Apply and release the brakes SLOWLY.
(c)
Check brake stacks movement to verify that brake is operating properly.
(d)
Check that BRAKE PRESS indicator gage on P3-1 panel indicates 3000 (|100) psi and remains steady during brake applications.
NOTE: If you push in the brake pedals fast, it will cause a
____ sudden pressure demand from the pump which is unable to respond quickly. As a result, a pressure decrease occurs in the system which causes the accumulator isolation valve to shift for less than a second or till pressure recovers. While this happens, the accumulator pressure bleeds down, Therefore, a 3000 psi indication on the gage may not hold. To prevent this, you must APPLY THE BRAKES SLOWLY.
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