4. Install Main Gear Forward Trunnion Bearing
A. Coat inside diameter of bearing housing with corrosion preventative compound (Fig. 401).
B. Prepare container with liquid nitrogen.
C. Immerse bearing in liquid nitrogen for sufficient time to allow even and thorough cooling.
WARNING: TEMPERATURE OF LIQUID NITROGEN IS -320°F. SAFETY PRECAUTIONS MUST BE TAKEN WHEN HANDLING CHILLED BEARINGS AND TOOLS.
D. Remove bearing from coolant and immediately install in bearing housing. There should be no metal to metal interference during insertion.
E. Push bearing down into position with mandrel.
F. Check that installed bearing is in correct alignment in bearing housing.
G. Allow bearing assembly to attain room temperature.
H. Remove all excess corrosion preventative compound with dry, clean cloth.
I. Install ring nut.
J. Support bearing assembly in holding fixture. Use spanner wrench to tighten ring nut 50 to 100 pound-feet.
K. Check that ball in bearing can be rotated by hand.
L. Drill 0.127 (+0.005/-0.000) inch diameter holes through ring nut from the two diametrically opposite holes in bearing housing that are best aligned between slots in ring nut.
M. Install rivets to lockring nut to bearing housing.
N. Install bearing assembly on trunnion link, and install trunnion link per 32-11-11.
32-11-101 Nov 15/68 Page 402
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
500 Main Gear Forward Trunnion Bearing Installation
Nov 15/68 Figure 401 32-11-101
Page 403
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
MAIN GEAR FORWARD TRUNNION BEARING - INSPECTION/CHECK
1. General
A. The main gear forward trunnion bearing should be examined for excessive diametral clearance whenever main gear shimmy problems exists. The bearing, bearing support, and bearing housing should be examined for wear per Fig. 601 when the bearing assembly or main gear is removed.
2. Main Gear Forward Trunnion Bearing Inspection
A. General
(1) This procedure provides a method to measure vertical and horizontal diametral clearance of the bearing. The diametral clearance of the forward trunnion bearing assembly (between trunnion link and bearing housing) must not exceed 0.030 inch for shrink fit bearing assemblies, or 0.050 inch for threaded bearing assemblies in any direction. If the clearance exceeds this limit, the bearing and wing fitting sleeve must be removed for examination and replacement as necessary.
B. Equipment and Materials
(1)
Dial indicator gage
(2)
Wood 2 x 4 inches approximately 8 feet long
(3)
Axle jack
C. Prepare for Examination
(1)
Jack airplane until main gear is clear of ground (Ref Chapter 7, Jacking Airplane).
(2)
Deflate main gear shock strut by removing dust cap from air charging valve and loosening air valve a maximum of two turns. Leave air valve open.
WARNING: DO NOT LOOSEN VALVE BODY UNLESS SHOCK STRUT IS COMPLETELY DEFLATED. AIR PRESSURE CAN BLOW VALVE BODY OUT, CAUSING INJURY TO PERSONNEL.
501
Aug 01/94 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 32-11-101 Page 601
D. Examine Main Gear Forward Trunnion Bearing
(1)
Examine vertical clearance of main gear forward trunnion bearing.
(a)
Clamp dial indicator to rear spar structure near forward trunnion bearing in a position to measure vertical clearance.
(b)
Push landing gear forward as far as it will go by applying force at wheels.
(c)
Set dial indicator in contact with trunnion as close as possible to forward trunnion bearing.
(d)
Adjust dial indicator to read zero.
(e)
Rock landing gear forward and aft by pushing and pulling at wheels.
(f)
Read bearing clearance on dial indicator. If clearance is greater than 0.030 inch for shrink fit bearing assemblies, or 0.050 inch for threaded bearing assemblies, check wear limits per Fig. 601 and replace parts as necessary.
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