Service Manual

Chapter 4
Hydraulic System
Table of Contents
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 2
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . 3
Hydraulic Hose and Fitting Information . . . . . . . . 3
HYDRAULIC SCHEMATICS . . . . . . . . . . . . . . . . . . 5
Two (2) Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 5
Four (4) Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 6
HYDRAULIC FLOW DIAGRAMS . . . . . . . . . . . . . . . 7
General Charge Pump Flow . . . . . . . . . . . . . . . . 7
Traction Circuit - Forward . . . . . . . . . . . . . . . . . . 8
Mowing Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Lift/Lower Circuit - Lifting Cutting Units . . . . . . . 10
Steering Circuit - R.H. Turn . . . . . . . . . . . . . . . . . 11
SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Hydraulic Pressure Test Kit . . . . . . . . . . . . . . . . 12
Hydraulic Tester. . . . . . . . . . . . . . . . . . . . . . . . . 13
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . 14
System Operates Hot . . . . . . . . . . . . . . . . . . . . 14
Machine Travels in One Direction Only . . . . . . . 14
Traction Response is Sluggish . . . . . . . . . . . . . 15
Machine Will Not Travel in Either Direction . . . . 15
Four Wheel Drive Does Not Engage . . . . . . . . . 16
Four Wheel Drive Does Not Disengage . . . . . . 16
No Cutting Units Operate . . . . . . . . . . . . . . . . . 17
All Cutting Units Operate Slowly . . . . . . . . . . . . 18
One Cutting Unit Does Not Operate . . . . . . . . . 19
One Cutting Unit Operates Slowly
and/
or Loses Power in Heavy Cutting . . . . . . 19
One Cutting Unit Will Not Stop Operating . . . . . 19
Cutting Unit(s) Do Not Lift or Lift Too Slowly . . . 20
Cutting Units Will Not Drop
or F
ollow Ground Contours . . . . . . . . . . . . . . 21
Cutting Unit(s) Drop From Raised Position
With
Lift Valve in Centered Position . . . . . . . 21
Cutting Unit(s) Lower or Raise Too Quickly. . . . 22
Steering Loss . . . . . . . . . . . . . . . . . . . . . . . . . . 22
TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Test No. 1: Checking Traction Circuit
W
orking Pressure or Relief Pressure. . . . . . . 24
Test No. 2: Checking Counterbalance Pressure 25
Test No. 3: Checking Mowing Circuit
W
orking Pressure or Relief Pressure. . . . . . . 26
Test No. 4: Checking Mowing Circuit Flow . . . . 27
Test No. 5: Checking Reel Motor Efficiency . . . 28
Test No. 6: Checking Steering Circuit
W
orking Pressure or Relief Pressure. . . . . . . 29
Test No. 7: Checking Lift Circuit
W
orking Pressure or Relief Pressure. . . . . . . 30
Test No. 8: Checking Charge Pressure
F
or Traction and Mowing Circuit . . . . . . . . . . 31
Test No. 9: Checking Traction Circuit
Re
ar Motor Pressure (4WD Only) . . . . . . . . .
32
ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Traction Pump Neutral Adjustment . . . . . . . . . . 33
Reel Speed Control Adjustment . . . . . . . . . . . . 34
REPAIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Removing Hydraulic System Components . . . . 35
SUNDSTRAND TANDEM PUMP REPAIRS . . . . . . 36
Shaft Seal Replacement . . . . . . . . . . . . . . . . . . 36
Trunnion Seal Replacement . . . . . . . . . . . . . . . 37
Check and High Pressure Relief Valves . . . . . . 38
Charge Pressure Relief Valve . . . . . . . . . . . . . . 39
Disassembly of Sundstrand Tandem Pump. . . . 40
Assembly of Sundstrand Tandem Pump . . . . . . 42
EATON PROPULSION PISTON PUMPS
REP
AIR INFORMATION (Traction/Mow Pump)
EATON GEAR PUMP REPAIR INFORMATION
(Auxiliary/Steering Pump)
SUNDSTRAND SAUER 15 SERIES AXIAL PISTON
MOT
OR SERVICE MANUAL
(Front Traction Motor)
EATON FIXED AXIAL PISTON MOTOR
REP
AIR INFORMATION
(Rear Axle 4WD Traction Motor)
CESSNA DIRECTIONAL CONTROL VALVE
SE
RVICE MANUAL
EATON GEAR MOTOR REPAIR INFORMATION
(Cutting Unit Reel Motor)
EATON CHAR-LYNN STEERING CONTROL UNITS
REPAIR INFORMATION
Reelmaster
®
335-D Page 4 - 1 Table of Contents