TM-9-2330-335-14-P
SEMITRAILER, TACTICAL, BREAKBULK/CONTAINER TRANSPORTER, 22-1/2 TON, RESET M871R, M871A1R AND M871A2R
TECHNICAL MANUAL; FIELD AND SUSTAINMENT MAINTENANCE MANUAL (INCLUDES REPAIR PARTS AND SPECIAL TOOLS LIST)
SEPTEMBER 2008
TM-9-2330-335-14-P - Page 529 of 640
0091-3
TM 9-2330-335-14&P
0091
PREMATURE WEAR/UPPER COUPLER FAILURE
00091
1.
A wavy upper coupler or severely distorted fifth wheel can result in inadequate surface contact (see Figure 4).
Inadequate contact dramatically increases surface pressures, pushing (scraping) grease out of the way and
leading to bare steel-on-steel contact. This will cause galling, premature wear, and potential failure as the fifth
wheel will begin to wear through the upper coupler.
2.
Identification.
Severe wear areas, galling, and/or dry spots in either the upper coupler or fifth wheel.
Figure 4.
Distorted Upper Coupler.
091
DIFFICULT RELEASE HANDLE OPERATION
00091
1.
Heavy loading and inadequate upper coupler strength can cause the upper coupler to “bow,” pulling the kingpin
upward when the trailer weight is resting on the fifth wheel (see Figure 5). The release handle will be difficult to
pull because the kingpin is pulling up on the fifth wheel locks.
2.
Identification.
The release handle is easy to pull when weight is removed from the fifth wheel top plate, but difficult to
pull when there is a load on the upper coupler and fifth wheel. This condition may not be detected by using a straightedge
because the upper coupler may be straight when unloaded, but deflect severely under load.
Figure 5.
Bowed Upper Coupler.
091
447-0097
447-0098
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