TM 9-2330-294-14
hydraulic jack from the tractor, to lift up the side of
the semitrailer for changing tires or other work.
Position B shows the use of the blocks at the
Wood blocks are provided, as basic issue items, for
semitrailer rear when loading a vehicle weighing
use in supporting the semi-trailer as shown in figure
more than 55 tons.
2-16. Position A shows the use of blocks, with a
2-18. Before-Operation Service
positioned in tractor fifth wheel. Secure kingpin to
tractor fifth wheel as directed in towing vehicle
Services to be performed by the operator or user are
operator's manual.
(4) Raise and secure landing gear in travel
operation services specified in table 3-1 should be
performed before using the semitrailer.
2-19. Operating the Semitrailer
air couplings and connect inter-vehicular emergency
a. Coupling Towing Vehicle to Semitrailer.
air hose to emergency coupling and service air hose
(1) Make sure that ramps are raised and secured
to service coupling in semitrailer (para 2-9) and open
towing vehicle shutoff cocks.
swingaway roller is secured in travel position (para
NOTE
2-16), and that retractable clearance lights are
The protection valve on the towing vehicle
secured in retracted position when semi trailer is
stops air supply to the semitrailer until a
empty (MPARA 2-6).
preset minimum tractor air pressure is
(2) Make sure air control handle is in proper
reached. For the M746 tractor, this pressure
is 65 psi. For the M123E2 tractor, this
CAUTION
pressure is 25-45 psi.
Do not allow kingpin to override fifth wheel.
(6) Connect intervehicular electrical cable to
(3) Couple semitrailer to towing vehicle by
backing tractor until semitrailer kingpin is