RENR8824 20 Page 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 SHUTTLE PILOT CONTROLLED 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) RENR8824 December 2006 990H Wheel Loader Hydraulic System BWX1-UP © 2006 Caterpillar All Rights Reserved Printed in U.S.A. Description Part Number Machine Location Schematic Location Accumulator Gp - Brake (Charged) 219-2949 1 B-7, C-7 Accumulator Gp - Pilot Oil (Charged) 226-0420 2 D-8 Adapter As 164-5633 3 F-6 Core As - Hydraulic Oil Cooler (Hydraulic Fan, Steering) 191-4600 4 C-11 Core As - Hydraulic Oil Cooler (Implement / Brake Supply) 261-3853 5 B-5 Cylinder Gp - Lift 9T-9569 6 H-3, H-4 Cylinder Gp - Lift (High Lift) 4Z-6390 7 H-3, H-4 Cylinder Gp - Steering (Left) 6E-1244 8 G-14 Cylinder Gp - Steering (Right) 9T-9568 9 G-14 Cylinder Gp - Tilt 251-1490 10 G-4 Cylinder Gp - Tilt (High Lift) 252-5213 11 G-4 Elbow - (Orificed) 127-9015 12 C-10 Filter Element As - Oil (Hydraulic) (Implement Tank) 4T-3134 13 B-5 Filter Element As - Oil (Hydraulic) (Steering Tank) 4T-3134 14 B-11 Filter Gp - Oil (Hydraulic Fan Motor Case Drain) 166-4647 15 C-11 Filter Gp - Oil (Hydraulic Fan Pump Case Drain) 166-4647 16 B-11 Filter Gp - Oil (Implement Pump Case Drain) 166-4647 17 A-4 Filter Gp - Oil (Steering Pump Case Drain) 166-4647 18 B-12 Fitting As (Quick Disconnect) 6V-3965 19 B-13 C-12 Motor Gp - Piston (Hydraulic Fan) 229-0100 20 D-10 Pump Gp - Gear (Pilot, Brake) 230-0914 21 B-7 Pump Gp - Piston (Hydraulic Fan) (Std, Mid Range Ambient Temperature) (High Ambient Temperature) 229-0099 235-0843 22 B-11 23 Pump Gp - Piston (Steering) 229-8604 24 B-12 Pump Gp - Piston (Tandem, Implement) 229-8602 25 B-4 Screen As (Hydraulic Tank) 9T-9227 26 B-11 Screen Gp 7J-2656 27 B-11 B-12 Tank & Filter Gp - Hydraulic (Hydraulic Fan, Steering) 6E-4683 28 Tank & Filter Gp - Hydraulic (Implement, Brake) 237-4228 29 B-5 Valve - Breaker Relief (Implement, Brake Tank) 133-1963 30 B-5 Valve - Breaker Relief (Steering, Hydraulic Fan Tank) 133-1963 31 B-11 Valve - Fluid Sampling (Steering, Hydraulic Fan Oil) 8C-3446 32 C-11 Valve (Filter Bypass) 9J-1988 33 B-11 Valve Gp - Check (Brake Oil Cooler Bypass) 6E-1454 34 C-11 Valve Gp - Check (Pilot) 9T-3096 35 G-4 Valve Gp - Check (Steering Quad) 104-7108 36 C-13 Valve Gp - Check (Steering Quad) 111-7775 37 D-14 Valve Gp - Combination (Pilot, Brake) 9T-9551 38 D-7 Valve Gp - Demand Fan 191-8735 39 C-9 Valve Gp - Main Control (2-Function) 270-1647 40 B-5 Valve Gp - Manifold & Relief (Main) 229-8721 41 B-3 Valve Gp - Pilot (2-Function) 177-4104 42 H-6 Valve Gp - Pilot (Stic Steering) 249-5615 43 B-15 Valve Gp - Pressure Reducing (Lowering Control) 6E-4286 44 D-13 Valve Gp - Relief (Brake System Backup) 234-0351 45 B-7 Valve Gp - Relief (Line, Lift Head End) 142-4281 46 C-4 Valve Gp - Relief (Line, Tilt Head End) 9T-6720 47 D-4 Valve Gp - Relief (Line, Tilt Rod End) 6E-3185 48 D-4 Valve Gp - Relief (Main) 143-8912 49 B-4 Valve Gp - Relief (Main) 4Z-6240 50 B-4 Valve Gp - Relief (Pilot) 6E-6293 51 C-7 Valve Gp - Relief (Pump Backup) 100-4335 52 E-13 Valve Gp - Relief (Steering Cylinder Crossover) 6E-3985 53 F-15 Valve Gp - Selector & Pressure Control (Dead Engine, Lift Arm Lower) 6E-3078 54 F-5 Valve Gp - Selector & Pressure Control (Steering) 6E-5566 55 C-13 Valve Gp - Shuttle 6R-0442 56 C-7 Valve Gp - Shuttle (Lift Cylinder) 4T-1860 57 F-4 Valve Gp - Shuttle (Load Signal, Steering, Implement) 4T-1860 58 F-14 Valve Gp - Steering (Std) 6E-2925 59 Valve Gp - Steering Neutralizer (Stic Steering) 9T-7426 60 F-13 C-15 Valve Gp - Unloading 117-7761 61 C-7 Valve (Primary Steering Pump Check) (Secondary Steering) 6E-3780 102 F-12 Pump Gp - Gear (Secondary Steering) 101-4007 101 D-12 Valve - Diverter (Secondary Steering) 2U-7345 103 F-12 Valve Gp - Relief (Secondary Steering) 6E-3986 104 E-12 Valve Gp - Selector & Pressure Control (Secondary Steering) 6E-5566 105 C-13 Valve Gp - Steering (with Secondary Steering) 6E-2923 106 F-13 Accumulator Gp - Ride Control (Charged) 219-7981 201 E-2 Valve Gp - Control 9T-9552 202 D-2 Valve Gp - Solenoid 152-8340 203 D-2 Component Locations Attachments (Secondary Steering) Ride Control MACHINE COMPONENT LOCATIONS 4 24 17b 13 29 30 16 39 16 17a 22 23 12 44 52 53 106 55 56 58 59 102 103 104 105 2 13 14 26 27 28 31 33 38 45 51 56 29 30 58 61 44 52 53 26 55 56 59 102 103 104 105 106 35 41 49 50 54 57 202 203 14 28 26 27 31 33 2 38 51 56 58 61 19f 18 19e 17a 19e 17b 17a 9 19f 18 12 4 5 5 25 25 15 20 34 60 37 43 42 3 40 46 47 48 21 1 45 101 43 42 1 37 35 54 57 202 203 23 22 20 15 10 11 10 11 3 6 7 40 46 47 41 49 50 6 7 6 7 9 8 101 201 201 8 9 201 20 48 39 60 34