32-11-00
 ALL  ú ú 01 Page 2 ú Feb 20/84
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
WALKING 
BEAM HANGER 
WALKING BEAM 
MAIN GEAR 
ACTUATOR 
GROUND SPEED  DOWNLOCK SPRING BUNGEE 
BRAKE CABLE 
(RIGHT GEAR ONLY)  REACTION LINK 
TRUNNION  UPLOCK ACTUATOR 
LINK 
DRAG STRUT  UPLOCK SPRING 
BUNGEE 
DOWNLOCK 
UNIVERSAL SIDE 
STRUT FITTING 
SIDE STRUT 
SHOCK STRUT 
UPLOCK ROLLER 
DAMPER 
HYDRAULIC 
LINE 
AXLE 
MAIN GEAR 
DAMPER 
TORSION 
LINKS  FWD  INBD 

Main Gear Component Location
Figure 1

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
 4.  Main Gear Drag Strut
____________________
 A.  The main gear drag strut stabilizes the shock strut in a fore and aft direction. The drag strut is in two parts. The upper drag strut is attached to a lug on the trunnion link at the top end, and to the lower drag strut at the bottom end. The lower drag strut is connected to the upper torsion link lugs on the outer cylinder, and to the side strut universal attachment on the shock strut (Fig. 1). A special shear bolt is used for the upper attachment to minimize damage to structure should landing gear receive a severe impact from the front. Clamps and attachments on the drag strut support linkage for the shock strut door.
 5.  Main Gear Torsion Links
_______________________
 A.  The main gear torsion links prevent rotation between shock strut inner and outer cylinders without affected the reciprocating action during normal operation of strut. The upper torsion link and bottom attachment of the lower drag strut share the same lugs on the shock strut outer cylinder. The lower torsion link is connected to lugs on the inner cylinder (Fig. 2). Upper and lower torsion links are joined at the forward ends by a single bolt.
 6.  Main Gear Damper
________________
 A.  The main gear damper prevents excessive vibration buildup in landing gear during high speed taxi and under heavy braking. The damper is a hydraulic unit containing an actuator, a compensator, and relief and check valves (Fig. 4). The main body of the damper is attached to the forward end of the upper torsion link. The actuator piston rod passes through the forward ends of both upper and lower links to provide an apex bolt. Rotary oscillation between the shock strut inner and outer cylinders is absorbed by the actuator piston displacing hydraulic fluid in the cylinder. The rate of displacement is controlled by the damping orifice in the actuator piston. The compensator is provided to maintain a pressure of 30 to 70 psi on the fluid contained in the actuator. A 3000 psi relief valve protects the actuator from very high pressures caused by thermal expansion of hydraulic fluid. A 70 psi relief valve protects the compensator from thermal expansion damage. Two check valves are provided to allow hydraulic fluid to enter the actuator and make up for slight leakage or to compensate for fluid contraction. A third check valve permits fluid to enter the unit from the hydraulic system A return and so keep the damper fully charged with fluid. Bleeder plugs are provided to enable trapped air to be cleared after disconnection of the hydraulic line or when filling an empty unit.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A

737-300/400/500
MAINTENANCE MANUAL

UPLOCK MECHANISM
UPLOCK SUPPORT FITTING  SIDE STRUT SUPPORT FRAME  FORWARD TRUNNION BEARING 
　
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