1. HYDRAULIC SYSTEM ............................ 6-3
1.1 Overview .................................................. 6-3
1.1.3 Circuit diagram for hydraulic system
........................................................ 6-3
1.1.1 Direction control solenoid valve ...... 6-3
1.1.2 Variable relief valve ........................6-3
1.2 Power steering ........................................ 6-4
1.2.1 Lifting and lowering reaping unit ..... 6-4
1.2.2 Turning and cornering..................... 6-5
1.3 Components of valve unit ......................... 6-6
1.3.1 Valve plate of hydraulic block DH .... 6-7
1.3.2 Reaping unit lifting solenoid valve
........................................................ 6-9
1.3.3 Reaping unit lowering solenoid valve
........................................................ 6-9
1.4 Steering clutch cylinder ......................... 6-10
1.5 Check for normal operation .................... 6-11
1.5.1 Checking solenoid valve with the
manual push button ...................... 6-11
1.5.2 Troubleshooting with hydraulic system
...................................................... 6-12
1.6 Check and adjustment ..........................6-13
1.6.1 Check for pressure of low pressure
relief valve .................................... 6-13
1.6.2 Check for pressure of high pressure
relief valve .................................... 6-14
1.7 Removal and installation ........................ 6-15
1.7.1 Removal of valve unit .................. 6-15
2. HST (HYDROSTATIC TRANSMISSION)
............................................................... 6-16
2.1 Overview ................................................ 6-16
2.1.1 Sectional view of HST .................. 6-17
2.2 Structure and function .......................... 6-18
2.2.1 Pump and motor ........................... 6-18
2.2.2 Variable swash plate ..................... 6-18
2.2.3 Charge pump ................................ 6-18
2.2.4 Charge relief valve ........................ 6-19
2.3 HST hose diagram and pressure check
............................................................... 6-20
2.3.1 Pressure check ............................ 6-20
2.4 HST troubleshooting list ......................... 6-21
2.5 Check and adjustment ..........................6-24
2.5.1 Adjustment of neutral (stop) position
..................................................... 6-24
2.5.2 Check for relief valve pressure ..... 6-24
2.6 Removal of HST .................................... 6-25
2.6.1 Removal without detaching reaping
unit ................................................ 6-25
2.6.2 Removal after detaching reaping unit
...................................................... 6-26
TABLE OF CONTENTS
HYDRAULIC SYSTEM
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