MASSEY FERGUSON MF 6700 S Series - Page 15

8.5.5.1 General ................................................8-69
8.5.5.2 4-wheel drive clutch - Service tools ............................8-69
8.6 Steering unit/Closed Center .......................................8-71
8.6.1 General .......................................................8-71
8.6.2 Hydraulic operating principle .......................................8-72
8.6.2.1 Reaction/non-reaction steering unit ............................8-73
8.6.3 Electrohydraulic operating principle ...................................8-75
8.6.4 Layout of steering unit components ..................................8-77
8.6.5 Removing and refitting the steering unit ...............................8-77
8.6.5.1 Refitting ................................................8-78
8.7 Steering unit/Open Center .........................................8-79
8.7.1 General .......................................................8-79
8.7.2 Principles of operation ............................................8-80
8.7.2.1 Reaction/non-reaction steering unit ............................8-82
8.7.3 Schematic diagram ..............................................8-84
8.7.4 Layout of steering unit components ..................................8-85
8.7.5 Removing and refitting the steering unit ...............................8-85
8.7.5.1 Refitting ................................................8-86
9 Hydraulics ................................................................9-1
9.1 HA140/Load Sensing ...............................................9-5
9.1.1 General ........................................................9-5
9.1.2 Principles of operation .............................................9-5
9.1.3 Trailer brake unit .................................................9-7
9.1.4 Layout of components .............................................9-9
9.1.4.1 Steering and cooling system ..................................9-9
9.1.4.2 High-pressure system ......................................9-11
9.1.4.3 Distribution unit — Power Beyond .............................9-12
9.1.5 Hydraulic tests .................................................9-14
9.1.5.1 General ................................................9-14
9.1.5.2 Auxiliary hydraulic system ...................................9-14
9.1.5.3 Steering system ..........................................9-19
9.1.6 Disassembly/reassembly ..........................................9-19
9.1.6.1 Variable displacement pump .................................9-19
9.1.6.2 Fixed displacement pumps ..................................9-21
9.1.7 Service tools ...................................................9-23
9.1.7.1 General ................................................9-23
9.1.7.2 Hydraulic test – Service tools ................................9-24
9.2 GPA20/Load Sensing ..............................................9-30
9.2.1 General .......................................................9-30
9.2.2 Principles of operation ............................................9-30
9.2.3 Layout of components ............................................9-32
9.2.3.1 Filtration and cooling .......................................9-32
9.2.3.2 Transmission lubrication system ..............................9-34
9.2.3.3 High-pressure system ......................................9-36
9.2.3.4 Low pressure system ......................................9-37
9.2.3.5 Distribution unit — Power Beyond .............................9-40
9.2.4 Hydraulic tests .................................................9-40
9.2.4.1 General ................................................9-40
9.2.4.2 High pressure system ......................................9-41
9.2.4.3 Low pressure system (20 bar) ................................9-47
9.2.4.4 Cooling and lubrication system ...............................9-52
9.2.5 Service tools ...................................................9-54
9.2.5.1 General ................................................9-54
9.2.5.2 Hydraulic test – Service tools ................................9-54
9.3 GPA20/Load Sensing/Right-hand cover plate .......................9-61
9.3.1 General .......................................................9-61
Table of contents
MF 6700 S series tractors
ACT0025630