RENR7528-04 July 2012 D8T Track-Type Tractor Hydraulic System J8B1-2393 KPZ1-3626 Printed in U.S.A. © 2012 Caterpillar, AllRights Reserved ONEPOSI TION TWO POSITI ON THREEPOSI TION VENT ED PRESSURI ZED RETURNABOVEFLUIDLEVEL RETURNBELOWFLUIDLEVEL LIN ESCROSSING LIN ESJOINI NG TWO- WAY THR EE- WAY FOU R- WAY SPRING CON TROLVAL VES RESTRICT ION LINERESTRICT ION (FIXED) PUMP (2-SECTION) SPRING (ADJUSTABLE) VA RI ABIL IT Y LI NEREST RI CT ION (VARIABLE) PRESSURE COMPENSATION PUMP (VARIABLE&PRESSURE COMPENSATED) MEASUREMENT PRE SSURE TEMPERATU RE FLOW ROTATING SHAFTS UNIDIRECTI ONAL BI DI RECT IONAL PUSH-PULLLEVER PEDAL GENERAL MANUAL PUSHBUTTON SPRING FIXED DISPLACEMENT VARIABLEDISPLACEMEN T NON-COMPENSATED UNIDIRECTIONAL BIDIRECTIONAL VALVE ENVELOPES VALVEPORTS FLUIDCONDITIONER PUMPORMOTOR FLUID POWER SYMBOLS UNIDIRECTIONAL BIDIRECTIONAL RELEASEDPRESSURE EXTERNALRETURN INTERNALRETURN REMOTESUPPLYPRESSURE SIMPLIFIED HYDRAULICPUMPS ACCUMULATORS SPRING LOADED GASCHARGED SOLENOID OR MANUAL SOLENOID &PILOT SOLENOID& PILOTORMANUAL SOLENOID SERVO THERMAL DETENT HYDRAULIC&PNEUMATICCYLINDERS DOUBLEACTING SINGLEACTING BASIC SYMBOL SPRING LOADED CHECKVALVES 2POSITION INFINITE POSITIONING FLOWINONE DIRECTION FLOW IN EITHER DIRECTION 3 POSITION CROSS FLOW PARALLEL FLOW INTERNALPASSAGEWAYS NORMALPOSITION AB P T AB P T SHIF TEDPOSITION INFI NITEPOSITI ON CONTROLVALVES ATTACHMEN T MANUALSHUTOFF SH UTT LE PI LOT CONTROLLED LINERESTRICTION (VARIABLE&PRESSURE COMPENSATED) MANUALCONTROLSYMBOLS HYDRAULICMOTORS FLUIDSTORAGERESERVOIRS CROSSING&JOININGLINES VALVES PILOT CONTROLSYMBOLS COMBINATIONCONTROLS BASICCOMPONENT SYMBOLS ENERGYTRIANGLES HYDRAULIC PNEUMATIC INTERNAL SUPPLYPRESSURE COMPLETE FIXED DISPLACEMENT VARIABLEDISPLACEMENT NON-COMPENSATED HYDRAULICSYMBOLS(ELECTRICAL) ELECTRICAL SYMBOLS TABLE 325-AG135 PK-14 HARNESSIDENTIFICATIONCODE THISEXAMPLE INDICATESWIRE135 INHARNESS“AG” 325-PK-14 WIREGAUGE WIRECOLOR CIRCUITNUMBER IDENTIFICATION WIRENUMBERIDENTIFICA TIONCODES CURRENT STANDARD PREVIOUSSTANDARD ELECTRICALSCHEMAT ICEXAMPLE HYDRAULI CSCHEMA TI CEXAMPLE 325-PK WIRECOLOR CIRCUITNUMBER IDENTIFICATION B WIRE WIRE (EXAMPLEVALVE) CURRENT STANDARD TRANSDUCER (FLUID) M ELECTRICMOTOR TRANSDUCER (GAS/ AIR) G GENERATOR PRESSURESWITCH ELECTRICALWIRE PRESSURESWITCH (ADJUSTABLE) TEMPERATURE SWITCH PRESSURE SWITCH TEMPERATURE SWITCH LEVEL SWITCH FLOW SWITCH ELECTRICALSYMBOLS(ELECTRI CAL) A CIRCUITNUMBER IDENTIFICATION WIRE COLOR WIREGAUGE T R E N R 7 5 2 8 0 4 3 0 P a g e , ( D i m e n s i o n s : 3 9 i n c h e s x 2 8 i n c h e s ) HD HC X2 X1 HFPD HPDL 13 HPTR HPRR HPSI HB HA HA HB 12 IMPLEMENT CONTROL VALVES HPAP CP1 HPS CP2 External Resolver Solenoid InletManifold Solenoid End Cover Main Relief Valve Charging Valve FRONT VIEW REARVIEW Blade Lift ControlValve Blade Tilt ControlValve Ripper Lift ControlValve Ripper Tip ControlValve Accumulator Pilot Oil Filter Pressure Reducing Valve (CallOut 12) PilotManifold Pilot Oil Filter 36 Dual Tilt Valve Solenoid 24 25 37 29 27 28 33 32 6 49 11 1 2 50 23 24 5 40 39 9 47 3 7 4 51 45 30 29 28 16 15 18 17 20 19 42 13 44 43 31 46 14 27 10 12 8 34 48 WINCH (36) Dual Tilt Valve (Attachment) 23 COMPONENT LOCATIONS 10 9 Pin Puller Solenoid (31) Pin Puller Valve (Attachment) 31 (9) Thermal Bypass Valve (10) Hydraulic Oil Cooler 1 (1) Steering, Charge and Fan Drive Pump Fan Drive Pump Steering Charge Pump Steering Pump 35 41 52 53 38 HPDR HPTL HPSO HPWO HPWI HPRL Check Part Numbers in the P arts Manuals for your Specific Machine. Description Part Number Machine Location Schematic Location Pump Gp -Steering, Charge & Fan Drive 212-0271 1 D-3 PumpGp- Piston(Steering) 205-1823 2 D-3 PumpGp- Piston(Fan) 204-2578 3 D-2 Motor Gp- Steering 252-5127 4 D-4 Motor Gp - Fan Motor With Anticav Valve 205-1821 5 E-1 Filter Gp- SteeringPumpCharge 211-6053 6 C3 PumpGp- Piston(Implement) 214-1091 7 B-2 Valve- In-lineResolver "T" 233-6942 8 E-7, F-5 Valve- Cooler Bypass 124-8335 9 D-1 CoreAs- Oil Clr 209-8380 10 D-1 Manifold- SuctionGallery 209-1392 11 B-2 Mani fold Gp -Cont (Manif ol d & Pi lot Pr essure Reduci ng Valve) 301- 2269 12 B- 5, C- 7 Accumulator 200-0750 13 B-5,C-7 Filter As -Hyd(Pilot System) 126-1813 14 B-4, C-6 ValveGp- Dozer Lift/Tilt 238-2753 Valve Gp -DozerLift/Tilt, Ripper Lift/Ti p 215-5615 Manifold Gp -I mplement Valve Inlet 213-4325 16 E-7,F-4 ValveGp- Dozer Lift 212-6322 17 E-7, F-4 ValveGp- Dozer Tilt 212-6323 18 D-7,EF-4 ValveGp- Ripper Lift 212-6324 19 C-4 ValveGp- Ripper Tip 212-6324 20 B-4 Cover 211-1751 21 B-5, C-7 Manifold- Tank Return 247-7788 22 C-4 ValveGp- Dozer QuickDrop 234-3042 23 F-3 Cyl Gp- Lift 250-5861 CylGp -L ift With Position Sensor 222-1222 Cyl Gp- Tilt 240-7347 25 E-2 Manifold-Ripper Cylinder SupplyAndReturn 211-9491 26 B-5 Cyl Gp- Ripper (Raise) 155-3653 27 B-6, C-6 Cyl Gp- Ripper Tip(Rh) 165-0102 28 C-6 Cyl Gp- Ripper Tip(Lh) 155-3652 29 B-6 Cyl Gp- PinPuller 6E-3113 30 A-6 ValveGp- PinPuller Control 188-6140 31 A-6 Tank 209-6686 32 A-3 Valve -Tank Pressure And VacuumRelief( Pl astic) 116-2810 33 A-4 ValveGp- ColdOil Relief 198-9220 34 B-2 Valve- Check 4E-1437 35 E-2 ValveGp- Dual Tilt Valve 217-4326 36 F-2 Cyl Gp- Dual Tilt 241-0550 37 F-2 Cyl Gp -Dual Tilt-Angle Blade 6E-0397 38 A-3 ValveGp- FanMotor Reversing 162-2191 39 F-1 Motor Gp -Fan Motor Without Anticav Valve 205-1820 40 E-1 PumpGp-fan 319-3593 41 D-2 ValveGp- Dozer Lift/tilt, Winch 215-6822 42 E-7 ValveGp- Cont (Winch) 213-4326 43 D-7 ManifoldGp 191-1443 44 D-7 WinchAr 216-9006 45 D-8 Sensor Gp -Pr essure (Pressur e Transducer- Impl ement Pump) 237- 0957 46 B- 5, C- 7 Sensor Gp -Pr essu re(Pre ssur e Tr ansduc er-Steer ing Char ge ) 224- 4535 47 C- 3 Swit ch As -Di ff er enti alPressur e(Steer ing Ch ar ge Fi lt er ) 25 3- 2673 48 C- 3 Sensor Gp -Temp (Hydraul ic Tan k- 2Wir e Passive Temp Sensor ) 145- 7028 49 B- 3 Se ns or Gp -Pre ss ur e (Pr es su re Tra ns du ce r-F anPu mp) 23 7- 095 7 50 B- 2 Sensor Gp -Speed / Direction (Steering Motor) 204-6204 51 D-4 ValveGp- 5SectionValveStack 238-2755 52 F-4 Valve Gp- AuxValve Section 273-5019 53 C-4, D-4, E-4 ATTACHMENTS DUAL TILT OPTION REVERSING FAN OPTION WINCH OPTION ELECTRICAL COMPONENTS Component Location 15 F-4 24 F-3 Tap Number Description Schematic Location HA Imp Pump Pressure E-7,F-5 HB ImpPump- Signal E-7,F-5 HPAP ( CP1) Hyd Pi lot Accumulator Pre ssur e C- 7,A-5 HP S (CP2 ) Regu la ted Pi lot Pr essure C- 6,A- 4 SLP ( HC) LSteeringL oop-Motor D-4 SRP (HD) RSteeringLoop-Motor D-4 SOS (F ) Char ge Pump Di scharge Pr essu re C- 3 X1 RightSteer Actuator D-3 X2 Left SteerActuator D-3 HPDR Hyd Pilot Dozer Raise E-6, F -4 HPDL Hyd Pilot Doer Lower E-7, F-5 HPTR Hyd Pilot Tilt Right D-7, E-5 HPTL Hyd Pilot Tilt Left D-6, E-4 HPRR Hyd Pilot Ripper Raise C-5 HPRL Hyd Pilot Ripper Lower C-4 HPSO Hyd Pilot Ripper Tip-out B-4 HPSI Hyd Pilot Ripper Tip-in B-5 HFPD Hyd Fan Pump Disch arge E-2 HPWO Hyd Pilot Winch Out D-6 HPWI HydPilot WinchIn D-7 Tap Location Pressure and Sampling 22 SOS F STEERING PUMP / MOTOR STEERING PUMP STEERING MOTOR TOP DOWN VIEW