SERV7106-11

Vol. 11, No. 1

November 2006

GLOBAL SERVICE LEARNING

TECHNICAL PRESENTATION

M325D MH / M325D L MH MATERIAL

HANDLERS
INTRODUCTION
(SECTION 1 of 7)

New Product Introduction

(NPI)
M325D MH AND M325D L MH
MATERIAL HANDLERS -
INTRODUCTION
AUDIENCE
Level II - Service personnel who understand the principles of machine systems operation,
diagnostic equipment, and procedures for testing and adjusting.
CONTENT
This presentation provides an introduction and describes the components and systems operation
of the M325D MH and M325D L MH Material Handlers main hydraulic system, swing system,
and travel drive system. This presentation may also be used for self-paced and self-directed
learning.
OBJECTIVES
After learning the information in this presentation, the technician will be able to:
1. identify the correct operation of the main hydraulic system, swing system, and travel
drive system; and,
2. diagnose problems in the main hydraulic system, swing system, and travel drive system.
REFERENCES
SERV 778 "M325C MH and M325C L MH Material Handlers - Systems
Operation" SERV1778
NPI "325D Hydraulic Excavator Introduction" V12N1 SERV7105-12
iTIM "325C Hydraulic Excavator Hydraulic Systems" SERV2701
STMG 774 "M318C MH/M322C MH Material Handler
Generator Control System SERV1774

PREREQUISITES
"Fundamentals of Mobile Hydraulics Self Study Course" TEMV3002
"Fundamentals of Power Train Self Study Course" TEMV3003
"Fundamentals of Electrical Systems Self Study Course" TEMV3004
"Fundamentals of Engines Self Study Course" TEMV3001

Estimated Time: 1.5 Hours

Illustrations: 48
Handouts: Section 1
Form: SERV7106-11
Date: Vol. 11, No. 1, 2006
© 2006 Caterpillar Inc.
SERV7106-11 -3- Text Reference
Vol. 11, No. 1, 2006

TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................5

MACHINE WALK-AROUND...................................................................................................10

OPERATOR'S STATION............................................................................................................30

CONCLUSION...........................................................................................................................52
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NOTES
SERV7106-11 -5- Text Reference
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M325D MH / M325D L MH MATERIAL HANDLERS

SYSTEMS OPERATION

© 2006 Caterpillar Inc.

INTRODUCTION

The M325D MH and M325D L MH Material Handlers incorporate innovations and

improvements from the M300C Series Excavators and the 300D Series Excavators. The new
machines are direct replacements for the M325C MH and M325D L MH Material Handlers.

The M325D MH and M325D L MH feature 190 net horsepower (140 kW). Both models are
powered by the new Cat C7 diesel engine with ACERT™ Technology, which works at the point
of combustion to optimize engine performance and provide low exhaust emissions. The
M325D MH and M325D L MH meet the EU sound regulations Stage II and EU emissions
regulations stage IIIA.

By combining ACERT™ Technology with the new Economy Mode, customers can balance the
demands of performance and fuel economy to suit their requirements and application.

The M325D MH/M325D L MH can be equipped with a grapple or a magnet to suit the needs of
a particular application.

The M325D MH and the M325D L MH feature a new cab for greater operator comfort, as well
as a new 2.6 m hydraulic cab riser with greater rigidity. The cab provides the operator with
excellent visibility of processing equipment, trucks, and railcars. The cab, consoles, and
joysticks have been improved to provide a better access and understanding of all functions.
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The ON/OFF grapple rotate function is replaced by the tool modular rotation with a sliding
switch on the left joystick to precisely position the tool.

The SmartBoom™ attachment, available on the M325D MH/M325D L MH, enhances

operation of the boom function and significantly reduces cycle times of the machine.

The M325D MH and the M325D L MH have the same basic components as each other. All
hydraulic and mechanical systems operation are similar for the two machines. The machines
also share many of the components of the 325D track hydraulic excavator.

The M325D L MH has a larger and more robust undercarriage than the M325D MH for
increased stability and durability.

The standard pressure on M325D MH and M325D L MH has been increased from 34,300 kPa
(4980 psi) up to 35,000 kPa (5080 psi). A Heavy Lift option is available at 36,000 kPa (5220
psi). With these higher pressures, lifting capacities have improved by approximately 3% to 6%.
The new hydraulic settings combined with new stems in main valve group will also improve
controllability to provide smoother and faster combined movements.

Two different material handling sticks are available. A straight stick is also available that can
be equipped with bucket linkage.

Optional equipment includes:

The Machine Security System (MSS), uses a special Caterpillar key with an embedded
electronic chip for controlling unauthorized machine operation.

Product Link, which provides all kinds of information and working parameters through a
satellite connection between an onboard computer and the machine. Product Link
provided easier fleet management and improved preventive maintenance.

A falling object guard is on the top and the front of the cab. The front guard swings out
for easier windshield cleaning.

These two new wheeled Material Handlers of 30 and 36 metric tons respectively, will meet
worldwide market requirements of the scrap, millyards, and ports dry bulk handling industries.
The M325D MH and M325D L MH are competing directly against Liebherr A934, A934HD,
Fuchs MHL350, and Atlas 1804.
SERV7106-11 -7- Text Reference
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M325D MH MATERIAL HANDLER

SYSTEM SIMILARITIES

M325C MH SYSTEM 325D MH M325C MH

OPERATOR'S
STATION X

ENGINE X

MONITOR X
PILOT
MANIFOLD X
HYDRAULIC
PUMPS X
MAIN CONTROL
VALVE X
TRAVEL MOTOR / X
TRANSMISSION

UNDERCARRIAGE/ X
STEERING AND BRAKES

The M325D MH/M325D L MH use systems similar to those found on the 325C MH and the
M322C MH. The M325D MH/M325D L MH has an upper structure that is similar to a 325C.
The undercarriage is the same as the previous models.

Operator's Station: The M325D MH/M325D L MH operator's station has been improved over
the previous models. The cab controls are similar to a M322C.

Engine: The M325D and 325D use the C7 ACERT™ engine.

Monitor: The M325D MH and M325D L MH uses the 325D monitor.

Pilot Manifold: The M325D MH/M325D L MH pilot manifold is similar to the pilot manifold
used on the M325C MH, except the location of the manifold has changed. Some of the
components in the manifold are also in different locations on the manifold.

Hydraulic Pumps: The M325D MH/M325D L MH use the same main hydraulic pumps, pilot
pump, and medium pressure pump as the 325D MH. The generator pump (if equipped) is
mounted to the pump accessory drive, the same as the 325D MH.
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Main Control Valve Group: The M325D MH/M325D L MH use a main control valve group
similar to the 325D MH. However, on the M325D MH/M325D L MH, the left travel spool is
used to control the stabilizers

The bucket valve and the attachment valve can be configured to meet the needs of the user as
to which valve controls the grapple.

The straight travel valve is still physically present on the valve, but is not used on the M325D
MH/M325D L MH.

Travel Motor and Transmission: The M325D MH/M325D L MH travel motor and
transmission are the same as the travel motor and transmission used on the M325C MH.

Undercarriage: The M325D MH and M325D L MH undercarriage is the same as the previous
models. The steering and brake systems are also similar.

NOTE: Plans are in place to remove the straight travel valve from the main control
valve group.
SERV7106-11 -9- Text Reference
11/06

M325D HYDRAULIC SYSTEMS

Steering
Cylinders

Travel Motor and Power Train

Boom Circuit Cab Medium
Swing Stabilizer Pressure
Aux Riser
Motor Stick Circuit Circuit Solenoids
Tool Circuit
Swivel Group
Circuit

Swivel

Medium Pressure Control

Main Control Valve Group Valve Group

Pilot Control Group

Travel Generator
Anti-Cav System
Valve
PRV Boom PRV Swing

Steering
Brake System
Pilot Manifold
System Cab Riser
Flow Control
Hydraulic Pumps Group

Grapple Flow Return System

Negative
Control Valve Flow Control Heavy
Group Valve Group Lift
Solenoid
Valve

Besides the changes discussed already, other changes to the machine hydraulic systems include:

- a different pilot control group.

- different pilot line routings to control the implement valves.

- changes to the priority valves for swing and stick.

- a single cylinder for the cab riser instead of two, along with a cab riser flow control
group.

- changes to the boom circuit as related to the plumbing for the cushion accumulators.

- changes to the medium pressure circuit.

- the addition of a heavy lift solenoid to increase the maximum lifting capability of the
machine.

These changes will be discussed in more detail in other sections of the training materials for the
M325D.
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2 3
4

MACHINE WALK-AROUND

The operator's station (1) is accessed from the left side of the machine. The operator's station
raises for increased visibility using the hydraulic cab riser (2).

Four stabilizers (not shown) are standard equipment on all M325D MH/M325D L MH material
handlers.

Two compartments (3 and 4) on the left side of the machine can be open to access various
machine components.

The M325D MH and M325D LMH can be equipped with a newly designed cab access system
(not shown). This cab features an additional cab platform with handrails located to provide the
operator with safe entry and exit from the cab.
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9
8
10

7
11 5 4
6 3
2

12

13

14

Behind the rear door on the left side are the:

- Air-to-Air Aftercooler (1)

- coolant overflow reservoir (2)

- primary fuel filter and water separator (3)

- high efficiency secondary fuel filter (4)

- priming pump (5)

- pilot manifold (6)

- cab lowering valve (7)

NOTE: Machines can also be equipped with an electrical priming pump.

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Behind the front door are the:

- primary and secondary air filter canister with dust ejector (8)

- Product Link ECM (9)

- Machine ECM (10) for the hydraulic pump and engine

- disconnect switch and breakers (11)

- air conditioner condenser (12)

- batteries (13)

- engine shutoff switch (14)

The radial seal air filter features a double-layered filter core for more efficient filtration. A
warning is displayed on the monitor when dust accumulates above a preset level.

NOTE: The previous models had three doors or covers on the left side of the machine
instead of two. One of the doors was for the cab riser.

The locations of some of these components shown in this illustration have changed from
the previous models to improve serviceability.
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1 3 4
2 5

On the right side of the machine are the:

- rear compartment (1) (where the pumps are located)

- hydraulic tank (2)

- fuel tank (3)

- access ladder (4)

- generator compartment (5)

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To access the ecological drain valve (1) for the hydraulic tank, a cover must be removed from
below the machine.

The fuel shutoff valve is located underneath the fuel tank. A cover must be removed to access
the valve

The fuel tank drain line (2) is routed to the fuel tank drain valve (not shown) located under the
main hydraulic pump group in the right rear compartment.
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8

5 9

2
7

In the rear compartment on the right side of the machine are the:

- hydraulic filter (1)

- charge pump filter (2)

- medium pressure circuit and cab riser manifold (3) with test ports and solenoid valves

- main hydraulic side-by-side pump group (4) (drive pump and idle pump)

- pilot system pump (5)

- steering and medium pressure system pump (6)

- engine oil filter (7)

- hydraulic system return filter (8)

The hydraulic tank (9) is located to the front of the rear compartment. The hydraulic sight
gauge (not shown) is mounted to the rear of the hydraulic tank and is visible through the rear
compartment.
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11

Under the tiltable cover (1) at the front of the machine is the generator compartment.

The Generator and Power Train ECM (3) is located under the cover (2) at the front of the
generator compartment on some machines.

This machine does not currently have a generator installed.

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1

3 12

4
13

After climbing on top of the machine, the fuel tank (1) and fuel fill cap and tube (2) are easily
seen, along with the top of the hydraulic tank (4) and the hydraulic return filter (5).

NOTE: The plug (3) is used for a refuelling pump attachment, which was not available
at first release of the M325D.
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6 5

11 9
7

2 10

14

Under the engine compartment hood are the:

- Caterpillar C7 direct injection, turbocharged ACERT™ engine (1)
- turbocharger (2)
- Engine ECM (3)
- HEUI fuel injection pump (4)
- engine oil fill cap (5)
- crankcase breather (6)
- muffler (7)
- radiator cooling fan (8)
- 65 amp alternator (9)
- air conditioner compressor (10)
- engine coolant sampling port (11)
SERV7106-11 - 19 - Text Reference
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The M325D MH and M325D L MH are equipped with the electronically controlled, six-
cylinder, turbocharged, Caterpillar C7 ATAAC diesel engine. The M325D MH and M325D L
MH meet the EU sound regulations Stage II and EU emissions regulations stage IIIA.

The M325D MH and M325D L MH feature 190 net horsepower (140 kW).

ADEMTM A4 (Advanced Diesel Engine Management) electronic control module manages fuel
delivery to get the best performance per liter of fuel. The controller uses sensors in fuel, air
intake, exhaust and cooling systems and provides flexible fuel mapping, allowing the engine to
respond quickly to varying application needs.

The ECM tracks engine and machine conditions while keeping the engine operating at peak
efficiency.

The Cat C7 features electronic controls that govern the mechanically actuated unit fuel
injection

system. Multiple injection fuel delivery involves a high degree of precision.

Precisely shaping the combustion cycle lowers combustion chamber temperatures, generating
fewer emissions, and optimizing fuel combustion,
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5
2 1

4 15

16

The radiator (1), radiator cap (2), radiator cooling fan (3), and Air-to-Air Aftercooler (4) are
also located in the engine compartment along with the hydraulic oil cooler (5)

The engine oil pan drain (6) is located below the engine.
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8
3

4
2

17

Next to the hydraulic tank and in the middle of the machine are the:

- main hydraulic control group (1)

- swing motor (2)

- cab riser valve group (3)

- cab riser accumulator (4)

- smart boom pilot activation solenoid valve (5)

- medium pressure circuit filter (6)

- air conditioner air dryer (7)

- air conditioner condenser fan (8)

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18

The swivel (1) is located next to the swing motor (2).

The upper section of the swivel provides an electrical connection for components in the
undercarriage, while the lower section directs hydraulic oil to and from the undercarriage
components.
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2 1

20

On the right side of the boom (1) are remote grease fittings (2) used to add grease to lubricate
pins and bushings for the boom and stick. The grease fitting mounting is a change from the
previous models

The boom can be equipped with boom four boom cushion accumulators (3) to cushion the load
when the machine is moving. Two accumulators are mounted to each boom cylinder. Before
the accumulators were mounted directly to the boom. The hose routing were also affected by
this change.
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22

Load control valve (1) are also available for the boom and stick circuits. Load control valves
are used to prevent the implement from falling if a hydraulic line breaks. The boom has a load
control valve for each cylinder.

The smart boom control valve group (2) is shown in the lower illustration.
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24

The new design of the parallelogram hydraulic cab riser offers increased visibility as well as
optimized operator comfort due to higher, larger and more robust structures.

A single cylinder is used for the latest cab riser. The previous version used two.

The activation of the hydraulic cab riser is modular allowing the operator to control the riser
speed and decrease shocks. In case of emergency, the cab can be lowered while using a cab
lowering lever (2) either inside the radiator compartment or inside the cab (not shown).
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1 25

26

Below the cab are the:

- Hand Metering Unit (1) (used for steering)

- brake valve (2)

- four brake accumulators (4)

Four brake accumulators are required to provide additional braking capacity, especially if the
engine stops running. Also, shown is the front wiper motor (3).
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28

3 6

The undercarriage (1) can be equipped with the standard size tires (2) as shown in the top
illustration M325D MH or large tires (2) as shown in the lower illustration for the M325D L
MH.

The larger tires allow the machine to lift more.

Both sizes of undercarriage are equipped with four stabilizers (4) as standard. Larger stabilizers
(5) are used on the undercarriage with large tires.

A tool box (storage compartment) (6) is located below the machine. There may be a storage
compartment on each side of the machine.
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30

On the smaller undercarriage machines the front axle(1) uses two oscillating cylinders (2) to
improve roading the machine.

The steerable front axle is equipped with tie rods (3)

The rear axle (4) is rigid.

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32

On the M325D L MH undercarriage, the two oscillating cylinders (5) are used for the rear axle
(4) to improve roading the machine.

The rigid, steerable front axle (4) is equipped with tie rods (3). The steering cylinder (2) is
mounted to the front of the front axle on both sizes of undercarriage.
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2

33

The oscillating axle accumulator (1) is located under the frame near the steering cylinders (2).

The accumulator acts as a shock absorber for the oscillating cylinders.

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3

1
2

34

The travel system for the M325D MH and M325D L MH is powered by the right (drive) main
hydraulic pump, and hydraulic oil flow is controlled by the travel spool in the main control
valve. The machines also have travel drive components that are mounted below the
undercarriage.

Some of the visible components in this view are:

- rear driveshaft (1) (red)

- front driveshaft (2)
- travel brake valve (counterbalance valve) (3)
- travel motor (4)
- transmission (5)

The minimum displacement of the travel motor is electronically controlled by the Power Train
ECM.

The two speed, planetary-type power shift transmission is equipped with two individual spring
applied and hydraulically released multiple disc clutches that actuate the parking brake and gear
selection.
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5
3
1

8
13

11
4 12
10

35

OPERATOR'S STATION

The operator's station is similar to the operator's station used on the previous machines. Access
to the operator's station is from the left side of the machine.

The right joystick (1), left joystick (2), stabilizer control lever (3), and pedals (4) actuate pilot
valves used to control the various machine hydraulic circuits. The steering wheel (5) is used to
steer the machine. The steering column is adjustable. Press the pedal (6) to release the column
in order to change the position of the steering wheel.

The emergency cab riser lowering valve (7) allows the operator to lower the cab if there is a
malfunction with the machine.

To start the machine, the left console (8) must be in the RAISED position. After starting the
machine, the console is lowered to signal the electronic control system to energize the
implement lockout solenoid valve mounted in the pilot manifold (shown later). The solenoid
allows pilot oil from the manifold to flow to the pilot valves below the joysticks, the stabilizer
control lever, the attachment pedal, and the travel pedal.
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Levers (9 and 10) near the door frame are used to release the door latch.

Two different types of seats are available, the standard seat and the pneumatic seat. The
pneumatic seat is shown in this illustration. The seat has a variety of adjustments that can be
made to the seat position, the backrest, the headrest, the back support, and other functions can
be adjusted.

The height and weight adjustment lever is a three-position lever (11). With the machine
running, pull up on the adjustment lever and place into the first position. The seat will
automatically adjust to the weight of the operator. Pull up on the adjustment lever and place
into the second position in order to raise the seat. Push down on the adjustment lever in order
to lower the seat.

To adjust the operator station forward or backward, pull up the lever (12). Move the operator
station to the desired position. Release the lever in order to lock the operator station in the
selected position.

To adjust the seat forward or backward, pull up the lever (13). Move the seat to the desired
position and release the lever in order to lock the seat in the selected position.

To adjust the height of the armrest, turn the knob (14) at the front of rear of the armrest to
select the desired height.

The seat may also be tilted. A lever (not shown) on the left side of the seat is depressed to
allow the seat angle to be adjusted.

The height of the headrest (if equipped) can be adjusted by pulling the headrest upward over
several increments. The angle of the headrest can be adjusted by pushing the headrest forward
or backward. To remove the headrest, pull the headrest over the stop at the end of the
increments.

The seat may also feature lumbar support. A seat heater is an option.
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MATERIAL HANDLER JOYSTICKS

Grapple CCW Grapple CW Cab Up

Cab Down

Not Used Not Used

Manual
Horn
Low Idle
SmartBoom
Magnet On / Off Disable
(Front) (Front)

LEFT RIGHT

36

This illustration identifies the function of the joystick switches on the joysticks.

The left joystick controls the auxiliary or grapple hydraulics (medium pressure) and the magnet
functions. The right joystick controls the cab riser function.

Before operating the magnet, make sure that the generator is the active tool. To make the
generator the active tool, select the generator using the monitor. Also, make sure that the
generator switch is in the ON position.

The SmartBoom™ function can be disabled momentarily using the front button on the right
joystick.

The manual low idle button allows the operator to easily reduce the rpm without touching the
throttle position switch.
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2

37

To apply the service brakes, depress the brake pedal (3). The brake pedal can be locked in the
fully-depressed position. The oscillating axle is locked and the parking brake is deactivated
when the brake pedal is in the fully-depressed position. The service brakes should be locked in
the fully-depressed position while the machine is being used in a stationary position. The
parking brake should not be used for operation of the machine in a stationary position. Use of
the parking brake while the machine is operated will lead to premature wear of the axles and
the transmission. Depress the small pedal (2) to release the brake pedal from the fully-
depressed position.

To travel FORWARD, the upper portion of the travel pedal (3) is depressed. To travel in
REVERSE, the lower portion of the travel pedal is depressed.

The Service Hour Meter (SMU) is located to the right of the travel pedal.
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1 3
2

5 7
6

38

The travel pedal (2) and the brake pedal (3) are shown in this illustration.

The travel pedal position sensor (1) on the travel pedal signals the position of the travel pedal to
the Power Train ECM.

The travel pedal is also connected to the travel pilot control valve (5). The travel pilot control
valve directs pilot oil to the travel spool in the main control valve group.

Below the brake pedal is a switch (7) that signals the Power Train ECM when the pedal is fully
depressed. When the switch is closed, the Power Train ECM de-energizes the oscillating axle
solenoid to lock the oscillating axle. The oscillating axle should be locked when the machine is
working in a stationary position or when traveling at a very slow speed.

The brake pedal is connected by a mechanical linkage (6) to the service brake control valve,
located under the cab.

If the brake pedal is fully depressed, the small pedal (4) must be depressed to release the brake
pedal.
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39

The steering wheel (1) is used to steer the machine. The control lever (2) features controls for
the window wipers and washer along with the horn control (3).

The monitor display screen (4) is mounted to the right of the steering wheel.
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3

7
9
8

40

The M325D MH/M325D L MH use the same monitor as the 300D Excavators. Features on the
monitor are the:
- clock (1)
- alert indicator (2)
- engine speed dial indicator (3)
- fuel level (4)
- hydraulic oil temperature (5)
- engine coolant temperature (6)
- event display (7)
- multi-informational display area (8)
- keypad cover (9) (Lower the cover to access the keys.)
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The monitor is a full color 400x234 pixels Liquid Crystal Display (LCD) graphic display.

The alert indicator or master caution lamp flashes when one of the critical conditions below
occurs:

- Engine oil pressure low

- Coolant temperature high

- Hydraulic oil temperature high

Under normal conditions or the default condition, the monitor display screen is divided into
four areas; clock and throttle dial, gauge, event display, and multi-information display.

Clock and Throttle Dial Area: The clock and the throttle dial position are in this area and the
gas-station icon with green color is also displayed.

Gauge Area: Three analog gauges, fuel level, hydraulic oil temperature, and coolant
temperature, are displayed in this area.

Event Display Area: Machine information is displayed in this area with the icon and language
related to machine events or warnings.

The monitoring system provides three warning categories.

- The first warning category requires only operator awareness. This type of warning will
be indicated by a message on the display screen.

- The second warning category requires a change to the machine operation or a change to
the maintenance of the machine. This type of warning will be indicated by a message on
the display screen and by a blinking of the Alert Indicator.

- The third warning category requires immediate shutdown of the engine. This type of
warning will be indicated by a message on the display screen, by a blinking of the Alert
Indicator, and by a buzzer. If multiple warnings are present in the system, the most
important problem is shown first. Press the right key or press the left key on the keypad
in order to view all of the warnings that are present in the machine. If no keys are
pressed within five seconds, the display will return to the most important problem.
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Multi-information Display Area: This area is reserved for displaying information that is
convenient for the operator. The "CAT" logo mark is displayed when information to display
does not exist.

The "MAIN MENU" in the multi-information display area allows the operator to view
information concerning the machine. This menu also allows the operator to change information
concerning the machine.

Push the menu key when the default display is active. The "MAIN MENU" will be displayed
with four new menu options: setting, maintenance information, performance, and service. For
more information on these menus, refer to the Operation and Maintenance Manual.
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4
1 3
2

5 6

41

The left console (1) must be lowered to activate the joysticks, stabilizers, attachment pedal, and
travel pedal. Pull the knob (2) in order to raise the left console and disable the joysticks,
stabilizers, attachment pedal, and travel pedal.

The left joystick (3) controls the stick and swing functions. The stabilizer lever (4) at the rear
of the left console controls the stabilizers. Use the stabilizer lever to raise or lower the
stabilizers.

Individual stabilizer switches are used to either lockout or release each stabilizer. Push down
on the top of one of the switches in order to prevent the movement of a single stabilizer. Push
down on the bottom of the switch in order to allow the movement of a single stabilizer.

Push down on the top of the hydraulic cab riser switch (6) in order to activate the hydraulic cab
riser. Push on the bottom of the hydraulic cab riser switch in order to deactivate the hydraulic
cab riser
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4 5
6

1 2

7 9

42

This illustration shows the right console. The joystick (1) on the console controls the boom and
the grapple.

The key start switch (2) is located behind the joystick. The detented throttle position switch (3)
selects one of the 10 engine speed settings.

A 24V (4) accessory plug is located at the front of the console.

The soft switch panel (5) on the right console allows the operator to control a number of
machine functions.

In the upper (6) and lower (7) switch panels are rocker switches used to control other machine
functions.

At the rear of the right console are the HVAC control panel (8) and a 12V accessory plug (9).

NOTE: The lower rocker switch panel is available with only a limited number of rocker
switches. The panel is used on other excavators besides the M325D. The switch shown
is for the radio. Additional switches could include mirror heater, seat heater and seat
cooler and/or high or low temperature for the seat heater.
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3 4 5
1 2

6 7 8
9 10

43

The soft switch panel in the right consoled is used to control various machine functions.
Oscillating Axle Control Switch (1): Use the oscillating axle control in order to lock and
unlock the oscillating axle. The indicator light will be on when the axle is locked. The
indicator light will be off when the axle is unlocked. Lock the oscillating axle when a load is
being carried.

The oscillating axle will also be locked when the left armrest is in the RAISED position or
when the service brake pedal is locked.

Travel Speed or Transmission Control (2): Push down on the button in order to select the
desired transmission gear. In order to put the transmission in first gear, push the button once.
The first indicator light will turn on when the transmission is in first gear. Push down on the
button twice in order to select second gear. The second indicator light will turn on when the
transmission is in second gear. Hold down the button for two seconds in order to activate the
automatic transmission shift. Hold down the button for two seconds again in order to
deactivate the automatic transmission shift. If the left armrest is in the RAISED position, the
transmission control automatically shifts to first gear.

The transmission automatically defaults to first gear. The transmission will stay in first gear
until the operator selects a different gear.
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Creeper Speed Control (3): Push down on the button in order to activate the creeper speed.
Use the creeper speed when a very low travel speed is desired. When the creeper speed is
activated, the indicator light will turn on. Push down on the button in order to deactivate the
creeper speed.

Creeper speed can be activated when the transmission is in first gear or second gear. Activation
of the creeper function will signal the power train drive motor to remain in a fully
UPSTROKED position, which provides low speed and high torque for travel.

Brake Characteristic Control (4): The brake characteristic control works in order to control
the reaction of the machine when the engine decelerates.

Push down on the button in order to turn the brake characteristic control to the Soft Mode.
Press the brake characteristic control button again in order to activate the Medium Mode. Press
the brake characteristic control button again in order to activate the Hard Mode.

Automatic Engine Speed Control (AESC) (5): The AESC automatically reduces engine
speed when the machine is inactive. The AESC system is designed to reduce fuel consumption
and noise. Slower engine speeds can also increase engine life.

The engine speed will automatically return to the setting of the engine speed dial when any
hydraulic function is activated. Disable the AESC during machine travel.

Mode I: Push down on the button in order to reduce the speed of the engine by 100 rpm
within a defined time. The indicator light on the left side of the switch will be
illuminated.

Mode II: Push down on the button again in order to reduce the speed of the engine to
1300 rpm within a defined time. The indicator light on the right side of the switch will
be illuminated.

The AESC delay times can be changed using the monitor panel or Caterpillar Electronic
Technician (Cat ET).

Parking Brake Control (6): To engage the parking brake, press the button for the parking
brake control. When the parking brake is in the engaged position, the light that is located on
the soft switch panel and the parking brake indicator that is on the monitor will come on.
Do not use the parking brake while the machine is in operation. Only use the parking brake
while the machine is parked. When the left console is in the raised position, the parking brake
will engage. The parking brake will also engage when low transmission clutch pressure is
detected.
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Travel Alarm Cancel Control (7): The travel alarm cancel switch can be used to stop the
travel alarm from sounding after 10 seconds. Push down on the travel alarm cancel switch in
order to turn off the alarm. Push the travel alarm cancel switch to the right in order to turn off
the alarm. The indicator light above the travel alarm cancel switch will turn on when the travel
alarm is cancelled.

If the machine is in motion or the door to the hydraulic cab riser is activated the travel alarm
will continue to sound for an additional ten seconds. The travel alarm is located under the
engine.

Heavy Lift Control (8): Push down on the button in order to turn on the Heavy Lift Mode.
Press the button again in order to return the normal conditions of the work tool.

The Heavy Lift Mode increases the relief pressure in the hydraulic circuit, which increases the
hydraulic force that is available for lifting operations. The cylinder speed is slower when this
mode is selected.

During normal excavation work, the heavy lift control must be in the OFF position.

Overload Warning Control (9): Turn the overload warning device to the ON position in
order to lift an object. In order to turn on the switch, push down on the switch. The indicator
light on the right side of the switch will turn off if the function is activated. The overload
warning device sounds when the machine is at the maximum lift capacity and the overload
warning indicator will be displayed on the monitor. Reduce the load if the alarm is activated.
Push down on the switch again in order to turn off the overload warning device.

Hydraulic Lockout Control Switch (10): Push this button in order to deactivate any function
that is controlled by the use of the joysticks and auxiliary pedals. The indicator light will turn
on when the hydraulic lockout function is activated. Lock the hydraulic system before roading
the machine. If the left armrest is in the RAISED position, the hydraulic system is disabled.
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1 2 3 4 6

44

The upper bank of rocker switches on the right console has the following switches.

Headlight and Front Flood Lamps Switch (1): The headlight and front flood lamp switch is
a three-position rocker switch.
- The bottom position turns off all of the lights.
- The center position turns ON the headlights and chassis lights.
- The top position turns on all of the lights.

Rear Flood Lamp Switch (2): The rear flood lamp switch is a two-position switch.
- The top position activates the rear flood lights.
- The bottom position deactivates the rear flood lights.

Beacon Switch (3)(not shown): The beacon switch is a two-position switch.

- The top position activates the beacon.
- The bottom position deactivates the beacon.
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Fine Swing Control Switch (4): The fine swing control switch is a two-position rocker
switch.
- The top position activates fine swing control. Fine swing control improves the swing
control during swing deceleration.
- The bottom position deactivates fine swing control.

SmartBoom™ Control Switch (5): The SmartBoom™ control switch is a three-position

switch.
- The SmartBoom™ enhances machine operation and reduces cycle times by allowing oil
to enter the boom circuit from the return circuit. The stick and swing functions have
significantly more oil available for use when the SmartBoom™ is activated.
- The top position activates the SmartBoom™ Up and Down Mode. In the SmartBoom™
Up and Down Mode, the boom is allowed to float up and down when the boom joystick
is moved to the BOOM DOWN position.
- The bottom position activates the SmartBoom™ Down Mode. In the SmartBoom™
Down Mode, the boom will lower under its own weight when the joystick is moved to
the BOOM DOWN position. In SmartBoom™ Down Mode, the joystick must be moved
to the BOOM RAISE position for the boom to raise.
- The center position turns the SmartBoom™ OFF.

Generator Switch (6): The generator switch is a two-position switch.

- The top position activates the generator.
- The bottom position deactivates the generator. The red switch on the generator switch
must be pressed to release the activated generator switch.

Blank (7): Not used.

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8

4
1 2
3 5 6 7

45

The heating and air conditioning system is electronically controlled. The control panel for the
heating and air conditioning system is located on the right console. The switches on the control
panel are:

On/Off switch (1): Push the ON/OFF switch in order to power on the system. Push the switch
again in order to power off the system.

Automatic control switch (2): In order to enter the full "AUT" Mode for automatic climate
control, push this switch. However, if the switch is pushed again, the air conditioning can not
be turned off. When the system is in full "AUT" Mode, specific functions can be manually
changed by pushing another switch.

If a specific function is manually changed, "AUT" will not appear in the display, but the
unchanged functions will remain in "AUT" mode. Even on a day that is sunny, a climate
control system with only a heater can cool the cab in full "AUT" mode if the ambient
temperature is no more than 20° C (68 °F).

Press the "AUT" switch for full "AUT" mode. Push temperature switch (3) in order to set the
desired temperature. The temperature is only shown in metric values. All other functions of
climate control will be handled automatically.
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In order to take advantage of the full "AUT" setting of the climate control system, always keep
the sunlight sensor clean. Do not obstruct the sunlight sensor. If the climate control system is
in the full "AUT" setting at engine start-up and the temperature inside the cab is too warm or
too cool, the damper for fresh air ventilation may automatically close for a few minutes. This
will help to bring the air temperature to the preset temperature more quickly.

Temperature Switch (3): These switches control the temperature of the air that is coming
from the air outlets in order to achieve the preset temperature. This preset temperature appears
on display. If the heating and air conditioning system is in the automatic mode, pushing these
switches changes the preset temperature.

LCD panel (4): The panel displays the settings of the HVAC system.

Fan switch (5): The fan switch directly controls the fan speed. If the climate control system is
operating in the automatic mode, pushing this switch overrides the automatically selected fan
speed.

Compressor switch (6): Push the switch in order to turn on the compressor or push the switch
in order to turn off the compressor. In humid conditions, the compressor may be used to
remove moisture from the air in the cab. In cool weather, operate the compressor weekly in
order to prevent leakage of the refrigerant gas and to help maintain the compressor in optimum
working order.

Defrost Mode (7): Depressing this switch will defog the windows. The air will also be
dehumidified while the compressor is running.

Air inlet select switch (8): This switch selects the position of the air inlet for recirculation or
for fresh air.

Air outlet select switch (9): This switch selects the position of each air outlet. Each switch
controls a different air outlet.
- upper body
- upper body and floor
- floor
- floor and defroster

NOTE: In order to convert the temperature reading from Degrees Celsius to Degrees
Fahrenheit, depress both keys of the fan switch at the same time for five seconds. The
same action is used for converting the temperature reading from Degrees Fahrenheit to
Degrees Celsius.
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46

The Electronic Technician (ET) diagnostic connector (1) is located below the HVAC control
panel at the rear of the right console.

The back-up switches (2 and 3) are located at the rear of the right arm rest. The back-up
switches provide limited machine operation when the engine and pump controller fails.

The top back-up switch (2) ACTIVATES/DEACTIVATES the Back-up Mode. When
Back-up Mode is active, a fixed powershift pressure is provided to the pumps. The fixed
powershift pressure limits maximum pump output and allows the machine to continue operating
in a Derate Mode. Machine productivity will be limited while the machine is in Back-up
Mode.

The lower back-up switch (3) is used to control the engine speed while Back-up Mode is active.
The lower back-up switch toggles to increase and decrease engine speed while in Back-up
Mode.
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1

47

The fuse panel (1) is located behind the operator's seat on the left side. The cover has been
removed. The cover is held in place with magnets.

A large storage compartment (2) is also located behind the seat.

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48

CONCLUSION

This presentation has provided information for the 325D MH and 325D L MH Material
Handlers from Caterpillar.

This presentation covered a machine walkaround and focused on the operator's compartment.

When used in conjunction with the service manual, the information in this package should
permit the technician to do a thorough job of analyzing a problem in these systems.

For service repairs, adjustments, and maintenance, always refer to the Operation and
Maintenance Manual, Service Manuals, and other related service publications.