Manitowoc MLC300 Service And Maintenance Manual

Reference Only
Manitowoc Published 11-22-17, Control # 257-02 8-1
MLC300 SERVICE/MAINTENANCE MANUAL UNDERCARRIAGE
8
SECTION 8
UNDERCARRIAGE
GENERAL
This section provides operational information and electrical
and hydraulic schematics for the following systems:
• Travel System
• Carbody Jack Cylinders
• Crawler Pin Pullers
• Carbody Track Tension Cylinders
Additional component information for these systems can be
found in the following sections of the Service Manual:
• Section 2: Hydraulics
• Section 3: Electrical
This section also provides repair, maintenance, and
adjustment procedures for the crawler and turntable.
HYDRAULIC TRAVEL SYSTEM
Travel System Overview
The travel system consists of two open-looped hydraulic
circuits. One circuit controls the left crawler, and the other
circuit controls the right crawler. Each open-looped circuit
consists of a directional control valve, one engine-driven
hydraulic pump, and one hydraulic motor.
Hydraulic Pumps
The hydraulic pumps used for the travel system are
electronically controlled, bi-directional, variable-
displacement type of pumps.
The right travel circuit uses pump 3. The left travel circuit
uses pump 4. Pumps 3 and 4 also provide hydraulic flow to
other open-loop functions.
Directional Control Valves
The directional control valve is an electronically controlled
proportional valve. Each directional control valve contains
two solenoids. Depending on which solenoid is energized,
the valve spool will move to a position that allows hydraulic
fluid from the pump to flow to the travel motor for either
forward or reverse travel direction.
When in neutral, the directional control valve spool is held in
the center position. When in this position, the forward and
reverse hydraulic lines to the travel motor are connected
through orifice passages in the valve spool.
Travel Motors
The travel motors are electronically controlled, bi-directional
variable-displacement type of motors that provide power to
planetary drives. Each travel motor is equipped with a park
brake that must be hydraulically released before travel can
occur.
The speed and direction of the travel motors are dependent
on the output flow volume of the travel pumps, the position of
the directional control valve, and the position of the travel
motor servo.
Joystick J2 Control
The pumps, directional control valves, and motors are
electronically controlled by the position of the corresponding
travel control handle (joystick J2) and the travel speed switch
located on the right console. Joystick J2 communicates with
the crane control system using the controller area network
bus (CAN Bus).
The left travel control handle controls pump 4, the left travel
control valve, and the left travel motor.
The right travel control handle controls pump 3, the right
travel control valve, and the right travel motor.

Manitowoc MLC300 Specifications

General

Brand	Manitowoc
Model	MLC300
Category	Construction Equipment
Language	English