Service Manual
HP2 Series Hydrostatic Tandem Pumps
5
Parker Hannifi n Corporation
Hydraulic Pump/Motor Division
Greeneville, Tennessee USA
HY13-1521-M1/US
General Information
Introduction
The three-column format used in this Service Manual will help make it easy for you to service a hydraulic pump.
Column 1 illustrates the procedure with photographs, Column 2 gives a brief key for each step, and Column 3
explains in detail the procedure you should follow. Pay special attention to the notes, cautions and warnings.
This manual contains troubleshooting information and checklists. With them you can diagnose a hydraulic
system problem without removing the HP2 Tandem Pump. The checklists will help you to determine where the
problem may be.
Item numbers on the exploded view correspond with item numbers used throughout the Service Manual.
As you gain experience in servicing the HP2 Tandem Pump, you may fi nd that some information in this Service
Manual could be clearer and more complete. If so, let us know about it. Don’t try to second-guess the Service
Manual; if problems occur that you cannot solve, please contact our service department at 423-639-8151, or
your local Parker approved distributor. Servicing the HP2 Tandem Pump should be safe and productive. Visit our
web site at www.parker.com/pumpmotor.
HP2 SERIES VARIABLE DISPLACEMENT, CLOSED LOOP DUAL PISTON PUMP
Large area cooling fi ns result in a cooler running system
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Center block and housings are sturdy, lightweight aluminum, excellent at dispersing
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heat, resulting in an overall cooler system
Replaceable bi-metal port plate increases contamination resistance and effi ciency of
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pump as well as serviceability
Forged trunnion shaft increases shaft strength and lengthens pump life
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Nylon caged thrust bearings improve lubrication and vibration absorption, thus
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lengthening life of pump
Compact size for similar systems for increased fl exibility in machine design
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Larger radial shaft bearings (20mm) provide additional side load capacity and less
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machine downtime
18% larger shaft than competitive pumps for reduced shaft breakage
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Smaller diameter pistons reduce load on thrust bearings compared to competitive
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pumps
Reduced maximum swash plate angle lowers piston-to-bore velocity and enables
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pistons to be more centered on the thrust bearing when swash plate is inclined
resulting in increased pump and bearing life
Two independently controlled, variable displacement, over-center piston pumps
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Single input drive shaft
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2.5 quart integral reservoir
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Integral fi lter and system cooling fan
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