Service Manual
109PW / PY Series
HOW TO USE THIS MANUAL
Each assembly is provided with an exploded
view showing the parts involved. The item
reference numbers in each illustration are for
assembly instructions only. See pages 124 and
125 for part names and descriptions. A complete
exploded view and item list of the pump is provided
at the end of this section.
GENERAL INSTRUCTIONS
Cleanliness is a primary means of ensuring
satisfactory life on repaired pumps. Thoroughly
clean all exposed surfaces prior to any type of main-
tenance. Cleaning of all parts by using a solvent
wash and air drying is usually adequate. As with any
precision equipment, all parts must be kept free of
foreign material and chemicals.
Protect all exposed sealing surfaces and open
cavities from damage and foreign material. The
external surfaces should be cleaned before
beginning any repairs.
Lip-type seals (shaft seals) are used on the input
shaft and directional control shaft of each Pump.
These seals can be replaced without major disas-
sembly of the unit. However, replacement of these
seals generally requires removal of the pump from
the machine. Upon removal, it is recommended that
all seals, O-rings and gaskets be replaced.
During installation, lightly lubricate all seals,
O-rings and gaskets with clean petroleum jelly prior
to assembly. Also protect the inner diameter of the
seals by covering the shaft with a cellophane (plastic
wrap, etc.) material.
Parts requiring replacement must be replaced from
the appropriate kits identiîżed in the Items Listing,
found at the end of this manual. Use only original
Hydro-Gear replacement parts found listed in BLN-
51427 (CD).
REPAIR - PW / PY SERIES PUMP
Repair - PW / PY Series Pump .......................................................................................... 109-126
How to Use This Manual............................................................................................................109
General Instructions ..................................................................................................................109
Tools and Torques .....................................................................................................................110
Return to Neutral Linkage .......................................................................................................... 111
Standard Control Arm Linkage ..................................................................................................112
Fan Assembly ............................................................................................................................112
Input Shaft Seal .........................................................................................................................113
Trunnion Arm Seal .....................................................................................................................113
Check Valves .............................................................................................................................114
Shock Valves .............................................................................................................................114
Bypass .......................................................................................................................................115
Charge Pump-Standard or Thru Shaft ....................................................................................... 116
Auxiliary Pump ...........................................................................................................................117
Auxiliary Pump (6cc Piston).......................................................................................................118
End Cap .....................................................................................................................................119
Cylinder Block ............................................................................................................................120
Block Spring and Thrust Bearings .............................................................................................121
Swashplate and Cradle Bearings ..............................................................................................121
Input Shaft .................................................................................................................................122
Trunnion Arm .............................................................................................................................123
Parts List ............................................................................................................................ 124-125