Chapter 4: Hydraulic System - Toro Groundsmaster 4300-D Service Manual

Table of Contents
Specifications ....................................................................................................................................... 4-3
Hydraulic System ............................................................................................................................... 4-3
General Information .............................................................................................................................. 4-4
Checking the Hydraulic Fluid ............................................................................................................. 4-4
Pushing or Towing the Traction Unit ................................................................................................... 4-5
Releasing Pressure from the Hydraulic System ................................................................................. 4-6
Traction Circuit Component Failure.................................................................................................... 4-7
Hydraulic Hoses................................................................................................................................. 4-8
Installing the Hydraulic Hose and Tube (O-Ring Face Seal Fitting)..................................................... 4-9
Installing the Hydraulic Fittings (SAE Straight Thread O-Ring Fitting into the Component
Port) ................................................................................................................................................. 4-11
Hydraulic Schematics .......................................................................................................................... 4-15
Hydraulic Flow Diagrams..................................................................................................................... 4-16
Traction Circuits ............................................................................................................................... 4-17
Mow Circuit ...................................................................................................................................... 4-20
Mow Circuit Cutting Deck Blade Braking .......................................................................................... 4-22
Lift Cylinder Circuit: Raise the Cutting Decks................................................................................... 4-25
Lift Cylinder Circuit: Lower the Cutting Decks .................................................................................. 4-27
Steering Circuit ................................................................................................................................ 4-30
Special Tools ....................................................................................................................................... 4-31
Hydraulic Pressure Testing Kit ......................................................................................................... 4-31
15 GPM Hydraulic Tester Kit (Pressure and Flow)............................................................................ 4-31
40 GPM Hydraulic Tester (Pressure and Flow)................................................................................. 4-32
Hydraulic Hose Kit ........................................................................................................................... 4-33
O-Ring Kit ........................................................................................................................................ 4-33
High Flow Hydraulic Filter Kit ........................................................................................................... 4-34
Hydraulic Test Fitting Kit................................................................................................................... 4-34
Spindle Plug..................................................................................................................................... 4-35
Wheel Hub Puller ............................................................................................................................. 4-35
Measuring Container........................................................................................................................ 4-36
Remote Starter Switch ..................................................................................................................... 4-36
Troubleshooting................................................................................................................................... 4-39
General Hydraulic System Problems ............................................................................................... 4-39
Traction Circuit Problems ................................................................................................................. 4-40
Mow Circuit Problems ...................................................................................................................... 4-41
Lift/Lower Circuit Problems .............................................................................................................. 4-42
Steering Circuit Problems ................................................................................................................ 4-43
Testing the Hydraulic System .............................................................................................................. 4-44
Testing the Traction Circuit-Charge Pressure .................................................................................. 4-46
Testing the Traction Circuit-Wheel Motor Efficiency......................................................................... 4-49
Testing the Traction Circuit-Piston Pump/Hydrostat Flow and Relief Pressure................................. 4-55
Testing the Mow Circuit-Circuit Pressure......................................................................................... 4-59
Testing the Mow Circuit-Deck Motor Efficiency/Case Drain ............................................................. 4-62
Testing the Mow Circuit-Relief Valve (PRV1) and (PRV2) Pressure................................................. 4-65
Testing the Mow Circuit-Gear Pump (P1) and (P2) Flow.................................................................. 4-69
Testing the Steering Circuit-Steering Control Valve, Relief Valve (R10) Pressure, and Steering
Cylinder............................................................................................................................................ 4-72
Testing the Steering Circuit-Gear Pump (P3) Flow .......................................................................... 4-75
Groundsmaster ® 4300-D
16226SL Rev C
Hydraulic System
Page 4-1
Chapter 4
Hydraulic System