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 528 of 640
TM 9-2330-335-14&P
0091-2
0091
CENTER LOADING
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1.
A Holland fifth wheel is designed to carry its load over the machined surfaces of the fifth wheel top plate. The
center section of the fifth wheel is purposely recessed to prevent it from carrying any vertical load (see Figure 2).
A “bowed” upper coupler can cause the vertical load to be concentrated in the center of the fifth wheel (see
Figure 3). “Center loading” causes the fifth wheel to act like a beam, flexing up and down over every bump and
ripple in the road. This continuous flexing can lead to top plate cracking.
2.
Identification.
Center loading can often be identified by shiny spots in the recessed area of the top plate and in the mating
area on the upper coupler. Additionally, a straightedge placed across the fifth wheel or upper coupler may reveal
inadequate contact area due to the deflections on the mating surfaces.
Figure 2.
Proper Load Distribution and Center Loading.
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Figure 3.
Bowed Upper Coupler.
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