Service Manual

55PJ 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 70 and 71
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
maintenance. 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
disassembly 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 identified 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 - PJ SERIES PUMP
Repair - PJ Series Pump ...................................................................................................... 55-72
How to Use This Manual..............................................................................................................55
General Instructions ....................................................................................................................55
Tools and Torques .......................................................................................................................56
Return to Neutral Linkage ............................................................................................................57
Standard Control Arm Linkage .....................................................................................................58
Fan Assembly..............................................................................................................................58
Input Shaft Seal ...........................................................................................................................59
Trunnion Arm Seal .......................................................................................................................59
Check Valves...............................................................................................................................60
Shock Valves ...............................................................................................................................60
Bypass ........................................................................................................................................61
Charge Pump-Standard or Thru Shaft.........................................................................................62
Auxiliary Pump .............................................................................................................................63
End Cap ......................................................................................................................................64
Cylinder Block .............................................................................................................................65
Block Spring and Thrust Bearings ...............................................................................................66
Swashplate and Cradle Bearings ................................................................................................66
Input Shaft ...................................................................................................................................67
Trunnion Arm ...............................................................................................................................68
Parts List ............................................................................................................................... 70-71