S 434-011
(1)
If the downlock actuator does not have hydraulic fittings installed in its ports, do the steps that follow:
(a)
Lubricate the new packing (10), union (11) , and reducer (12) with hydraulic fluid.
CAUTION: MAKE SURE THAT THE REDUCER AND UNION ARE INSTALLED IN THE
_______ CORRECT PORTS ON THE DOWNLOCK ACTUATOR. INCORRECT INSTALLATION OF THE FITTINGS WILL CAUSE THE HYDRAULIC LINES TO BE CROSSED AND SUBSEQUENT MALFUCTION OF THE EXTENSION/RETRACTION SYSTEM.
(b)
Install the packing (10) and union (11) in the RETRACT port of the actuator.
(c)
Install the packing (10) and reducer (12) in the EXTEND port of the actuator.
(2)
Fill the actuator with hydraulic fluid.
S 614-012
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(3) S 434-013Put a plug in the hydraulic fittings.
(4) S 644-023Apply grease to the bolts, washers, and nuts for the antirotation bracket.
(5) S 434-024Install the bolts, the washers, and the nuts to connect the anitrotation bracket to the downlock spindle. Install one washer behind each nut.
(6) S 424-014Install the head end of the actuator.
CAUTION:_______ USE EXTREME CARE WNEN YOU INSTALL THE ACTUATOR CLEVIS PIN TO PREVENT CONTAMINATION OF THE HYDRAULIC PORTS OR SEALS.
(a) (b) (c) (d) (e) Apply lubricant to the clevis pin assembly (8).Put the head end of the actuator in position on the downlock assembly and install the clevis pin assembly (8).Apply grease to the washer (6) and nut (5), and install them on the clevis pin assembly (8).Tighten the nut (5) to 100-200 pound-inches (11.3-22.6 newton-meters).Install the pin (9) through nut (5).
(7) S 424-016Install the rod end of the actuator. (a) Apply grease to the bolt (1), washer (3), and nut (4). (b) Install the bolt (1), washer (3), and nut (4) to connect the rod end of the actuator to the downlock assembly. (c) Tighten the nut (4). Use the minimum torque required to bring the nut (4) and washer (3) against the upper downlock link without a load applied to the actuator lugs. After you do this, increase the torque 10-20 pound-inches (1.1-2.2 newton-meters). If it is necessary, loosen the nut to the nearest lock position to allow installation of the pin (7). (d) Install the pin (7) through the nut (4).
(8) S 644-017Lubricate the actuator at the grease fittings with grease.
NOTE:____ If the actuator has two grease fittings at the head end, lubricate only one grease fitting.
(9) S 864-018Remove the pressure from the left hydraulic system and the hydraulic reservoir.
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S 434-019
(10)
Connect the hydraulic lines to the actuator clevis pin.
S 214-020
(11)
Do a check of the actuator to make sure it is installed properly.
(a)
Pressurize the left hydraulic system (AMM 29-11-00/201).
WARNING:_______ MAKE SURE THAT THE NOSE AND MAIN LANDING GEAR DOWNLOCKS
ARE INSTALLED BEFORE YOU MOVE THE LANDING-GEAR-CONTROL
LEVER. IF THE CONTROL LEVER IS MOVED WITHOUT THE
DOWNLOCKS INSTALLED, THIS CAN CAUSE THE LANDING GEAR TO
RETRACT AND INJURE PERSONNEL AND/OR DAMAGE EQUIPMENT.
(b)
Move the landing-gear-control lever from DN to UP and back to DN several times. Keep the control lever in each position for approximately one minute.
(c)
Make sure the actuator or the hydraulic connections show no hydraulic leaks when the landing-gear-control lever is in both the UP and the DN positions.
(d)
Make sure the landing-gear-control lever is in the DN position, then do the steps that follow: 1) Make sure the downlock assembly stays in the locked
position.
2) Look for the indications that follow on the pilot's center instrument panel: a) The amber GEAR light is off. b) The green LEFT and RIGHT gear down lights are on.
(e) Remove hydraulic power if it is not necessary (AMM 29-11-00/201).
S 864-021
(12)
Make sure the hydraulic reservoir is at the correct level.
(a)
Fill the hydraulic system if it is necessary (AMM 12-12-01/301).
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757 MAINTENANCE MANUAL 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：757 AMM 飞机维护手册 起落架 CHAPTER 32 - LANDING GEAR 2(50)
