9.3.2 Principles of operation ............................................9-61
9.3.3 Description and operation of the variable displacement pump ...............9-63
9.3.4 Priority block ...................................................9-66
9.3.5 Layout of components ............................................9-71
9.3.5.1 View of the assembly ......................................9-71
9.3.5.2 Blown-up view ...........................................9-73
9.3.6 Identification of channels and ports ..................................9-75
9.3.7 Disassembly/reassembly ..........................................9-77
9.3.7.1 Removing and refitting the hydraulic cover plate ...................9-77
9.3.7.2 Removing and refitting the variable displacement pump .............9-80
9.3.8 Service tools ...................................................9-82
9.3.8.1 General ................................................9-82
9.3.8.2 Load Sensing/Right-hand cover plate - Service tools ................9-83
9.4 GPA20/Load Sensing/Left-hand cover plate .........................9-84
9.4.1 General .......................................................9-84
9.4.2 Principles of operation ............................................9-84
9.4.3 Layout of components ............................................9-86
9.4.3.1 View of the assembly ......................................9-86
9.4.3.2 GPA20 exploded view ......................................9-87
9.4.3.3 Identification of ports and channels on the cover plate ..............9-88
9.4.4 Disassembly/reassembly ..........................................9-88
9.4.4.1 Removing/refitting the LS cover plate ..........................9-88
9.4.4.2 Removing and refitting the charge pump ........................9-88
9.4.4.3 Replacing the charge pump seals .............................9-91
9.5 Load Sensing/Linkage spool valve .................................9-94
9.5.1 General .......................................................9-94
9.5.2 Principles of operation ............................................9-95
9.5.3 Schematic diagram ..............................................9-97
9.5.4 Removing/refitting the linkage spool valve .............................9-98
9.5.4.1 Removal ...............................................9-98
9.5.4.2 Refitting ................................................9-99
9.5.4.3 Disassembly .............................................9-99
9.5.4.4 Reassembly .............................................9-99
9.5.4.5 Final steps ..............................................9-99
9.6 Load Sensing/Rear auxiliary spool valves ..........................9-101
9.6.1 General ......................................................9-101
9.6.2 Mechanical auxiliary spool valves ...................................9-104
9.6.2.1 Principles of operation .....................................9-104
9.6.2.2 Control cables ..........................................9-105
9.6.3 Electrohydraulic auxiliary spool valves ................................9-105
9.6.3.1 Principles of operation .....................................9-105
9.6.3.2 Working pressure block ....................................9-108
9.6.4 Adjustments and bleeding ........................................9-109
9.6.4.1 Spool valve cables .......................................9-109
9.6.5 Disassembly/reassembly .........................................9-111
9.6.5.1 Removing/refitting the rear spool valves ........................9-111
9.6.5.2 Spool valve lever .........................................9-113
9.7 Load Sensing/Front auxiliary spool valves .........................9-115
9.7.1 General ......................................................9-115
9.7.2 Principles of operation ...........................................9-117
9.7.3 Working pressure block ..........................................9-121
9.7.4 Removing/refitting the front spool valves .............................9-121
9.7.4.1 Removing the front spool valves — Dyna-4 and Dyna-6 .............9-122
9.7.4.2 Removing the front spool valves — Dyna-VT ....................9-123
9.7.4.3 Refitting the front spool valves ..............................9-124
9.7.4.4 Disassembling/reassembling the spool valve assembly .............9-125
9.8 GPA20/Open Center ..............................................9-127
Table of contents
MF 6700 S series tractors
ACT0025630
To Next Page
Loading...
