(c)
Remove the four bolts that attach the small bearing housing (6) to the cargo door structure.
(d)
Remove the spring attach bolt (11).
NOTE: When you remove the spring attach bolt (11), look at the
____ relation between the hook return spring (5) to the bellcrank (8). The relation between the hook return spring and the bellcrank during removal must be the same during installation for the correct operation of the hook mechanism.
(e)
Move the bellcrank (8) in the direction of the hook actuator
(1)
and remove the hook return spring (5).
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747-400 MAINTENANCE MANUAL
TASK 52-34-20-404-007
3. Hook Return Spring - Installation_________________________________
A. General
(1)
This procedure is for the forward lower lobe cargo door. The aft lower lobe cargo door is equivalent.
B.
Consumable Materials
(1)
D00013 Grease, MIL-G-23827
C.
References
(1)
IPC 52-34-07
D.
Access
(1)
Location Zone 122 Forward Cargo Container Compartment, Forward Half 142 Aft Cargo Container Compartment
(2)
Access Panel
821R Door - Forward Cargo Compartment
822R Door - Aft Cargo Compartment
E.
Procedure
S 024-008
(1)
Install the hook return spring (5) as follows (Fig. 401):
(a)
Put the hook return spring (5) in its position on the bellcrank (8).
NOTE: The flat surface of the hook return spring must have the
____ same relation to the bellcrank as when it was removed (View C, Fig. 401). When the spring is installed correctly, it will always drive the hook toward the open position.
(b)
Install the four bolts that connect the small bearing housing
(6)
to the cargo door structure.
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747-400 MAINTENANCE MANUAL
(c)
Put the countersunk washers below the boltheads.
(d)
Install the four bolts that connect the large bearing housing
(4)
to the cargo door structure.
(e)
Put the countersunk washers below the boltheads.
(f)
Install the spring attach bolt (11).
NOTE: With the hook actuator in the open position, it is
____ necessary to rotate the spring approximately 90 degrees counter-clockwise to attach the bolt. With the hook actuator in the closed position, it is necessary to rotate the apring approximately 210 degrees counter-clockwise to attach the bolt.
S 434-010
(2) Install the bolt that attaches the pushrod (7) to the bellcrank (8).
S 434-011
(3) Install the torque tube coupling (9) as follows:
(a) Before installation, apply grease to the ends of the torque
tube coupling (9) that have splines.
(b) Install and connect the torque tube coupling (9) with the two
clamps (3).
(c) Put the countersunk washers below the bolthead.
S 864-012
(4) Remove the DO-NOT-CLOSE tag and close these circuit breakers for the
applicable cargo door:
(a) P59 Aft Equipment Panel
1) AFT CARGO DOOR POWER UNITS
(b) P414 Power Distribution Center - Left
1) 414A21 LOWER CARGO DOOR FWD
2) 414F15 CARGO DOOR CONTROL FWD
3) 414F16 CARGO DOOR CONTROL AFT
S 714-013
(5) Close the cargo door.
S 864-015
(6) Operate the cargo door through one complete cycle to examine how the
hook pins engage when the cargo door closes.
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