Bad Boy 1022H - Chapter 4: HST System

1. INTRODUCTION ...................................... 4-3
1.1 Introduction ............................................4-3
2. GENERAL SPECIFICATIONS ................. 4-4
3. COMPONENT LOCATION ....................... 4-5
3.1 Hydraulic hoses and lines ......................4-5
3.2 Hydrostatic transmission .......................4-5
3.3 Hydrostatic control linkage ....................4-6
3.4 Hydrostatic system schematic ............... 4-7
4. TROUBLESHOOTING ............................. 4-8
5. DIAGNOSTICS ...................................... 4-10
6. THEORY OF OPERATION -
HYDROSTATIC SYSTEM ......................4 -11
6.1 Pump, motor circuit (variable pump) .... 4 -11
6.2 Charge circuit ...................................... 4-12
6.3 HST operation .................................... 4-12
6.4 Handling precautions ........................... 4-14
6.4.1 Storage .......................................... 4-14
6.4.2 Operating oil (hydraulic oil) ............ 4-14
6.4.3 Pollution management ................... 4-14
6.4.4 Shaft coupling ................................ 4-14
6.4.5 Defect of lever shaft ....................... 4-14
6.4.6 Starting .......................................... 4-15
6.4.7 Oil temperature management ........ 4-15
6.4.8 Piping ............................................. 4-15
6.5 Regular check &
replacement cycle of hydraulic oil ....... 4 -16
7. TESTS AND ADJUSTMENT ...................4- 17
7.1
Hydrostatic pedal and neutral adjustment .. 4-17
7.2 Hydrostatic pump pressure test ........... 4-18
7.3 Charge pump pressure test .................4-20
7.4
Hydraulic system bleed procedure ...............4-21
8. REPAIR .................................................. 4-22
8.1 Hydrostatic splitting ..............................4 -2 2
8.2 Hydrostatic overhaul ............................4-24
8.2 .1 Tools ..............................................4-24
8.2.2 Pre-disassembly precautions ....... 4-24
8.2.3 Disassembly procedure .................4 -25
8.2.4 Pre-assembly precautions ............. 4-31
8.2.5 Assembly procedure ......................4-31
CHAPTER 4 HST SYSTEM
TABLE OF CONTENTS