UENR7800
November 2020 FLUID POWER SYMBOLS
BASIC COMPONENT SYMBOLS
MAIN AUX
PUMP OR MOTOR FLUID CONDITIONER SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION PUMP PUMP
(FIXED) (2 - SECTION) (VARIABLE & PRESSURE
COMPENSATED)
VARIABILITY SPRING LINE RESTRICTION PRESSURE HYDRAULIC PNEUMATIC LINE RESTRICTION ATTACHMENT
(ADJUSTABLE) (VARIABLE) COMPENSATION ENERGY TRIANGLES (VARIABLE & PRESSURE
COMPENSATED)
VALVE ENVELOPES VALVES VALVE PORTS
ONE POSITION TWO POSITION THREE POSITION TWO - WAY THREE - WAY FOUR - WAY
CONTROL VALVES CHECK VALVES
AB A B
P T P T
BASIC SPRING SHUTTLE PILOT
NORMAL POSITION SHIFTED POSITION INFINITE POSITION
SYMBOL LOADED CONTROLLED
FLUID STORAGE RESERVOIRS
VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL
777E Off-Highway Truck
MEASUREMENT ROTATING SHAFTS
Cooling System PRESSURE TEMPERATURE FLOW UNIDIRECTIONAL BIDIRECTIONAL
COMBINATION CONTROLS
KYD1-UP
KZD1-UP
SOLENOID SOLENOID SOLENOID SOLENOID & SERVO THERMAL DETENT
OR MANUAL & PILOT PILOT OR MANUAL
MANUAL CONTROL SYMBOLS
PUSH - PULL LEVER MANUAL SHUTOFF GENERAL MANUAL PUSH BUTTON PEDAL SPRING
RELEASED PRESSURE PILOT CONTROL SYMBOLS REMOTE SUPPLY PRESSURE
EXTERNAL RETURN INTERNAL RETURN SIMPLIFIED COMPLETE INTERNAL
SUPPLY PRESSURE
ACCUMULATORS CROSSING & JOINING LINES HYDRAULIC & PNEUMATIC CYLINDERS
SPRING LOADED GAS CHARGED LINES CROSSING LINES JOINING SINGLE ACTING DOUBLE ACTING
HYDRAULIC PUMPS HYDRAULIC MOTORS INTERNAL PASSAGEWAYS
FIXED VARIABLE DISPLACEMENT FIXED VARIABLE DISPLACEMENT INFINITE
DISPLACEMENT NON-COMPENSATED DISPLACEMENT NON-COMPENSATED POSITIONING 3 POSITION 2 POSITION
UNIDIRECTIONAL UNIDIRECTIONAL
FLOW IN ONE PARALLEL CROSS FLOW IN
BIDIRECTIONAL BIDIRECTIONAL DIRECTION FLOW FLOW EITHER
DIRECTION
© 2020 Caterpillar. All Rights Reserved. CAT, CATERPILLAR, LET’S DO THE WORK, their respective logos, “Caterpillar Corporate Yellow”, the
PUBLICATIONS.CAT.COM “Power Edge” and Cat “Modern Hex” trade dress as well as corporate and product identity used herein, are trademarks of Caterpillar and may not
be used without permission.
ELECTRICAL SYMBOLS TABLE
HYDRAULIC SYMBOLS (ELECTRICAL)
G
M
TRANSDUCER TRANSDUCER GENERATOR ELECTRIC MOTOR
(FLUID) (GAS / AIR)
PRESSURE SWITCH PRESSURE SWITCH TEMPERATURE ELECTRICAL WIRE
(ADJUSTABLE) SWITCH
(Dimensions: 34 inches x 28 inches)
WIRE NUMBER IDENTIFICATION CODES
ELECTRICAL SCHEMATIC EXAMPLE HYDRAULIC SCHEMATIC EXAMPLE
UENR7800
CURRENT STANDARD CURRENT STANDARD
HARNESS IDENTIFICATION CODE THIS EXAMPLE
INDICATES WIRE 135 IN HARNESS “AG”
WIRE WIRE
COLOR
CIRCUIT NUMBER
325-AG135 PK-14 IDENTIFICATION WIRE COLOR
CIRCUIT NUMBER WIRE GAUGE*
*Wire gauge is shown in AWG (American Wire Gauge)
IDENTIFICATION but could also be shown in metric denoted with mm 325-PK
PREVIOUS STANDARD
WIRE WIRE COLOR
24 Page,
325-PK-14 B A
CIRCUIT NUMBER WIRE GAUGE* (EXAMPLE VALVE)
IDENTIFICATION *Wire gauge is shown in AWG (American Wire Gauge)
but could also be shown in metric denoted with mm
7 6 5 4 3 2 1
F TEMPERATURE CAP PRESSURE F
SENSOR 15 PSI
OVER FILL
ELBOW
VENT LINES
VENT LINES
E E
HEAD
THERMOSTAT
WATER PUMP HOUSING
CYLINDERS
WATER PUMP
WATER PUMP INLET BONNET
OUTLET BONNET
D
ENGINE D
BLOCK
ENGINE OIL COOLER
BYPASS
BONNET
(Dimensions: 34 inches x 28 inches
OIL FROM OIL TO ENGINE
ENGINE BLOCK OIL FILTER
UENR7800
C SOS PORT C
DRAIN
POWER TRAIN OIL COOLER RADIATOR
BONNET
24 Page,
OIL TO OIL FROM
TRANSMISSION SUMP TORQUE CONVERTER
B B
DRAIN
OIL FROM HYDRAULIC OIL TO REAR RIGHT BRAKE
BRAKE COOLING CIRCUIT AND FRONT BRAKES
REFERENCE HYDRAULIC SCHEMATIC
OIL FROM HYDRAULIC OIL TO REAR LEFT BRAKE
BRAKE OIL COOLER BRAKE COOLING CIRCUIT
REFERENCE HYDRAULIC SCHEMATIC
COOLING FLOW COLOR DESCRIPTIONS
HOT FLOW
A A
VENT LINE
DRAIN CAB HEATER COOLED FLOW
CAB HEATER CORE FLOW
DRAIN
OVERFILL
THIS SCHEMATIC IS FOR THE 777E OFF-HIGHWAY TRUCK COOLING SYSTEM
Do not operate or work on this product unless you have
MEDIA NUMBER: UENR7800
read and understood the instruction and warnings in the SCHEMATIC PART NUMBER: 579-2721, CHANGE: 00, VERSION: -
relevant Operation and Maintenance Manuals and
relevant service literature. Failure to follow the instruc-
Components are shown installed on a fully operable machine with the key and engine off, transmission shifter
tions or heed the warnings could result in injury or in neutral and with parking brake set.
death. Proper care is your responsibility. Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations.
Refer to the Parts Manual using a specific serial number prefix in SIS before ordering parts from this schematic.
7 6 5 4 3 2 1
