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TM 5-3805-293-10
INTRODUCTORY INFORMATION
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THEORY OF OPERATION
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INTRODUCTION
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1. The 120M Motor Grader consists of the following functional systems: engine, powertrain, brakes, electrical,
steering, and hydraulics.
2. This work package explains how the systems and components of the machine work together. A functional
description is provided for each major component and system.
3. The 120M Motor Grader is an all-purpose, medium sized, wheeled vehicle used for spreading and evening
various types of granular material (dirt, stone, sand, etc.). Power is provided by a Caterpillar in-line, six-
cylinder, direct injected, diesel engine. Hydraulically operated implements allow blade positioning for forward
or backward grading, ditch or embankment grading, and snow removal. A scarifier allows loosening of
compacted material prior to grading. Front leaning wheel and frame articulation provide maximum
maneuverability. The grader has a sound-suppressing Rollover Protective Structure (ROPS) cab with
insulation, heater, and windows, which allows for all-weather operation.
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