RENR8121-00 30 Page, EAR RENR8121 October 2004 789C Off-Highway Truck Hydraulic System 2BW659-UP © 2004 Caterpillar All Rights Reserved Printed in U.S.A. Description Media Number Specifications SENR1521 Systems Operation SENR1522 Testing and Adjusting SENR1523 Disassembly and Assembly SENR1524 Specifications: (Hydraulic System) SENR1531 Testing and Adjusting: (Hydraulic System) SENR1532 Specifications: (Steering System) SENR1525 Testing & Adjusting: (Steering System) SENR1526 Specifications: (Air System & Brakes) SENR1527 Testing & Adjusting: (Air System & Brakes) SENR1528 Specifications, System Operation, Testing & Adjusting: (Oil Evacuation System) RENR2223 Specifications: (Suspension Cylinder) SENR1529 Schematic (Electrical System) SENR1535 Automatic Electronic Traction Aid (AETA) SENR2986 Additional Manuals Related Manuals Power Train Machine Systems Electrical System: Tap Number Description Schematic Location Machine Location A Low Steering Pump Pressure I - 15 41 B High Steering Pressure (Accumulator) H - 13 23 C Hoist Pump Pressure (Front) G-5 63 D Hoist Pump Pressure (Rear) G-5 63 E Left Rear Brake Cooling Pressure J - 10 1 F Left Rear Parking Brake Pressure I - 10 32 G Right Rear Parking Brake Pressure C - 10 32 H Rear Service Brake Pressure F - 11 32 J Front Service Brake Pressure F-3 35 K Torque Converter Charge Pump Pressure I-6 64 L Torque Converter Lock-up Clutch Pressure I-5 10 M Torque Converter Outlet Pressure I-4 24 N Transmission Lube Pump Pressure E - 15 43 O Left Brake Pressure Test Port F - 10 2 P Transmission Charge Pump Pressure E - 16 37 Q Right Brake Pressure Test Port E - 10 2 R Hoist System Power Unit (Auxiliary) C-9 38 S Steering System Power Unit (Auxiliary) G - 15 36 X Transmission System Oil (Sampling) D - 15 57 Y Hoist and Torque Converter System Oil (Sampling) H-7 19 Z Streeting System Oil (Sampling) I - 16 36 Tap Locations Pressure, Sampling, and Sensor Machine Location Schematic Location Description Part Number 1 B - 11,J - 11 Service and Parking Brake (Rear) 5T-4489 2 F-9 Traction Control Valve 9G-9208 3 B-8 Hoist Cylinders 9T-2807 4 F-9 Check Valve (Electric Drive Pump) 9T-3086 5 E - 10 Electric Drive Pump (Parking and Secondary Brake Release) 5T-1060 6 I-9 Brake Valve (Parking and Secondary) 149-4133 7 J-9 Orifice 122-7765 8 J-9 Screen 6E-5065 9 H-9 Check Valve 138-4733 10 I-5 Lockup Clutch and Synchronizing Valve (Torque Converter) 8E-6146 11 D - 2,I - 2 Service and Parking Brake (Front) 5T-5070 18 J-9 Makeup Tank for Service Brake Oil 6E-1851 19 H-7 Hydraulic Filter (Parking Brake Release) 6P-4603 20 B - 3,C - 3 Bypass Switch (5) 9X-7781 21 J-4 Diverter Valve (Torque Converter and Front Brake Cooling) 105-0170 24 I-5 Relief Valve (Torque Converter Outlet) 9W-7403 26 G - 11 Air Over Hydraulic Cylinder (Brake) 8W-3405 27 J-5 Screen (Torque Converter and Front Brake Cooling) 6E-1349 28 J-3 Oil Cooler (Front Brake Cooling) 141-4108 29 E-3 Orifice 8W-4042 32 F - 11 Slack Adjuster (Rear) 5T-7670 33 B - 10 Oil Cooler (Rear Brake Cooling) 141-4108 34 B - 10 Screen 6E-6640 35 F-2 Slack Adjuster (Front) 2G-5900 38 D-8 Control Valve 132-2048 39 B-7 Counterbalance Valve (Hoist) 132-7102 40 F-4 Pump Drive 2A-6516 41 G - 14 Piston Pump (Steering) 6E-5650 45 C - 3,D - 3 Hoist Screens 6E-5471 48 G-7 Rear Brake Cooling Pump Section 3E-3882 49 H-6 Parking Brake Release Pump Selection 6T-6147 50 H-6 Torque Converter Charging Pump Section 6T-6147 51 H-6 Torque Converter Scavenge Pump Section 6T-6147 52 E-7 Hydraulic Tank (Torque Converter, Hoist, Brake and Transmission) 161-0536 53 E-6 Suction Screens 9T-3850 58 H-4 Air Breather (Hoist, Torque Converter and Brake) 8X-4575 61 B - 11,I - 11 Service and Parking Brake (Rear) 5T-4489 62 J-6 Relief Valve (Torque Converter Inlet) 3P--0348 63 G-5 Hoist and Rear Brake Cooling Gear Pump 139-2454 64 I-6 Hydraulic Filter (Torque Converter) 4T4760 66 D - 2,I - 2 Service and Parking Brake (Front) 5T-5070 73 H-5 Torque Converter 116-5811 80 D-9 HARC Valve 177-8840 80 E-9 Check Valve 9T-6173 81 D - 10 Accumulator Grp. 241-3147 12 I - 15 Pressure Switch (Steering Pump Oil Low) 3E-7809 13 I - 15 Orifice 8X-7851 14 G - 13 Metering Pump (Steering) 9T-1318 22 J - 13 Steering Cylinders 4T-6797 23 I - 13 Steering Control Valve 9T-1318 30 I - 17 Accumulator Charging Valve 148-9237 36 J - 16 Solenoid and Relief Valve (Steering) 6E-3965 41 H - 15 Piston Pump (Steering) and Pressure Compensator Valve 6E-5656 42 I - 15 Orifice 1T-0936 46 J - 17 Pressure Switch (Steering Pump Oil High) 3E-6461 47 J - 16 Steering Accumulators 6E-6611 60 G - 16 Filter (Steering Pump Case Drain) 4T-4284 67 G - 16 Steering Tank 155-6660 68 G - 17 Steering Tank Filter 9J-5461 69 H - 17 Brake Relief Valve 9T-0818 70 J - 16 Check Valve (Steering) 9T-2553 20 D - 16 Bypass Switch 9X-7781 37 E - 14 Magnetic Screen (Transmission) 7T-4554 40 C - 15 Pump Drive 2A-6516 43 E - 16 Oil Cooler (Transmission) 4W-5056 44 D - 15 Relief Valve (Transmission Cooler Inlet) 2P-2859 52 B - 14 Hydraulic Tank (Torque Converter, Hoist, Brake and Transmission) 161-0536 53 B - 16 Suction Screen 9T-3850 54 C - 15 Transmission Charging Pump Section 156-8525 55 C - 15 Transmission Planetary 156-8525 56 C - 15 Transmission Scavenge Pump Section 156-8525 57 D - 16 Hydraulic Filter (Transmission Charging) 6P-4603 59 E - 13 Air Breather (Transmission) 6G-0078 65 D - 15 Hydraulic Filter (Transmission Lubrication) 6P-4603 Component Locations Steering Hydraulic System Transmission Hydraulic System B C D G F H J K L M N Q P S Z X Y L E E F G H O Q E E 16 Hydraulic Symbols (Electrical) Electrical Symbols Table 325-AG135 PK-14 Circuit Identification Number Wire Color Wire Gauge Harness identification code This example indicates wire 135 in harness "AG". 325-PK-14 Wire Gauge Wire Color Circuit Number Identification Wire Number Identification Codes Current Standard Previous Standard Electrical Schematic Example Hydraulic Schematic Example 325-PK Wire Color Circuit Number Identification B A Wire Wire (EXAMPLE VALVE) Current Standard Transducer (Fluid) Transducer (Gas / Air) G Generator Electrical Wire Pressure Switch M Electric Motor Pressure Switch (Adjustable) Temperature Switch T Pressure Symbol Temperature Symbol Level Symbol Flow Symbol Electrical Symbols (Electrical) ONE POSITION TWO POSITION THREE POSITION VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL LINES CROSSING LINES JOINING TWO-WAY THREE-WAY FOUR-WAY SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION (FIXED) 2-SECTION PUMP MAIN AUX. SPRING (ADJUSTABLE) VARIABILITY LINE RESTRICTION (VARIABLE) LINE RESTRICTION VARIABLE and PRESSURE COMPENSATED PRESSURE COMPENSATION PUMP: VARIABLE and PRESSURE COMPENSATED ENERGY TRIANGLES HYDRAULIC PNEUMATIC MEASUREMENT PRESSURE TEMPERATURE FLOW ROTATING SHAFTS UNIDIRECTIONAL BIDIRECTIONAL PUSH-PULL LEVER PEDAL GENERAL MANUAL PUSH BUTTON SPRING MANUAL CONTROL SYMBOLS HYDRAULIC MOTORS FIXED DISPLACEMENT VARIABLE DISPLACEMENT NON-COMPENSATED UNIDIRECTIONAL BIDIRECTIONAL HYDRAULIC PUMPS FLUID STORAGE RESERVOIRS CROSSING AND JOINING LINES VALVE ENVELOPES VALVE PORTS BASIC COMPONENT SYMBOLS FLUID CONDITIONER PUMP or MOTOR FLUID POWER SYMBOLS FIXED DISPLACEMENT VARIABLE DISPLACEMENT NON-COMPENSATED UNIDIRECTIONAL BIDIRECTIONAL VALVES PILOT CONTROL SYMBOLS RELEASED PRESSURE EXTERNAL RETURN INTERNAL RETURN REMOTE SUPPLY PRESSURE SIMPLIFIED COMPLETE INTERNAL SUPPLY PRESSURE ACCUMULATORS SPRING LOADED GAS CHARGED SOLENOID or MANUAL SOLENOID and PILOT SOLENOID and PILOT or MANUAL COMBINATION CONTROLS SOLENOID SERVO THERMAL DETENT HYDRAULIC AND PNEUMATIC CYLINDERS DOUBLE ACTING SINGLE ACTING BASIC SYMBOL SPRING LOADED CHECK VALVES TWO POSITION INFINITE POSITIONING FLOW IN ONE DIRECTION FLOW ALLOWED IN EITHER DIRECTION THREE POSITION CROSS FLOW PARALLEL FLOW INTERNAL PASSAGEWAYS NORMAL POSITION AB PT AB PT SHIFTED POSITION INFINITE POSITION CONTROL VALVES ATTACHMENT MANUAL SHUTOFF (12) Steering piston pump (16) Pressure compensator valve (17) Pump drive (A) Low steering pump pressure test port. (1) Low pressure switch from steering piston pump (5) Steering solenoid and relief valve (6) Steering check valve (18) Steering relief valve (19) Steering solenoid valve (Z) Steering system oil sampling port (S) Steering system Power Unit (Auxiliary) (8) Steering pump case drain filter (9) Steering filter (10) Steering hydraulic tank (13) Breaker relief valve (B) High steering pressure test port. Top view of Rear Brake Lines (E) Left Rear Brake Cooling Pressure (N) Pressure Tap for Transmission Lube Pump. (J) Pressure Tap for Front Service Brake (H) Pressure Tap for Rear Service Brake. (O) Left Brake Pressure Test Port (Q) Right Brake Pressure Test Port. 5 N Z 1 1 1 2 3 L M 1 2 6 7 3 4 5 6 23 2 P 1 2 3 Y D C B E H G F J S 1 4 2 3 K H O Q 2 3 4 5 6 1 11 10 40 3 14 18 19 20 20 21 22 23 24 27 22 28 29 30 HH 32 33 35 36 37 38 41 43 45 20 46 48 53 52 54 57 58 60 61 62 64 65 70 59 66 67 63 12 47 26 20 80 (1)Torque converter outlet relief valve. (M)Pressure tap for torque converter outlet pressure. (2) Torque converter inlet relief valve. (L) Pressure tap for lockup clutch pilot oil. (1) Torque converter, hoist, brake, and transmission hydraulic tank (2) Torque converter, hoist, and brake section (3) Transmission section (1) Pump drive (2) Hoist and rear brake cooling gear pump (front section) (3) Hoist and rear brake cooling gear pump (rear section) (4) Inlet from the hydraulic tank (5) Inlet from the hydraulic tank (6) Outlet to the hoist control valve (7) Outlet to the hoist control valve (Y) Parking Brake Filter Oil (Sampling) (6) Parking brake release hydraulic filter (23) Bypass switch (16) Torque converter and front brake cooling screen (P) Pressure tap for the transmission charging section (1) Torque converter and front brake cooling oil cooler (5) Torque converter and front brake cooling diverter valve (2) Rear brake oil coolers (3) Screens for the rear brake oil coolers (H) Pressure tap for Rear Service Brake (F) Pressure tap for Left parking brake release pressure (G) Pressure tap for Right parking brake release pressure (1) Torque converter hydraulic filter (2) Inlet line (3) Outlet line (4) Bypass switch (K) Torque Converter Charge pump pressure 16 12 17 A 19 5 18 6 10 13 8 9 73 55 56 51 49 50 68 69 13 34 44 42 7 8 9 39 81 A O R 14 60 67 68 28 29 21 56 59 10 24 62 6 12 27 19 20 22 11 46 47 23 36 70 30 66 43 33 44 64 63 40 41 57 65 53 52 48 49 50 51 56 54 35 5 4 18 26 26 38 39 45 20 2 70 71 55 80 37 32 61 1 72 72 A K B C D J M N Z P R S Y X Side view of steering oil lines (1) Steering accumulators (2) Pressure switch for high pressur oil from the steering piston pump (4) Steering cylinders (7) Steering control valve (8) Steering pump case drain filter (10) Steering hydraulic tank (12) Steering piston pump (14) Pressure switch for low pressure oil from the steering piston pump (15) Orifice (16) Pressure compensator valve (AA) Pressure tap for low pressure oil from the steering piston pump Top view of steering oil lines (1) Steering accumulators (2) Pressure switch for high pressur oil from the steering piston pump (3) Accumulator charging valve (4) Steering cylinders (5) Steering solenoid and relief valve (7) Steering control valve (8) Steering pump case drain filter (10) Steering hydraulic tank (12) Steering piston pump (14) Pressure switch for low pressure oil from the steering piston pump