Description

Sauer Danfoss Series 45 2002 Service Manual – OEM Axial Piston Pump Service Guide

If you are wrenching on a Sauer Danfoss Series 45 open-circuit axial piston pump (Frame K or L), you need the 2002 OEM manual on the bench, not some aftermarket copy that guesses on case pressure limits. This 31-page service manual is what the factory issued for the Series 45 – the same document BTI used to support its rockbreaker equipment. I have burned enough billable hours chasing down a control valve issue caused by a bad reprint spec. Skip the guessing. Get the original.

Safety gets its own section starting on page 4. The manual covers unintended machine movement, flammable cleaning solvents, fluid under pressure, and personal safety. Read that before you break a single tee fitting. The hydraulic fluid under pressure in a Series 45 can inject into your skin – the manual spells that out clearly. After safety, you get a general description with a sectional view of the pump and control, plus a pictorial circuit diagram. That diagram alone saves you half an hour of tracing lines.

Safety Precautions: Unintended Machine Movement and Fluid Under Pressure

The manual does not waste words on theory. On page 4 the safety precautions hit the four killers: unintended machine movement, flammable cleaning solvents, fluid under pressure, and personal safety. If you are working on a machine with a Series 45 pump, de-energize the system and block any motion before you crack a line. The manual warns that even with the engine off, accumulators can hold enough pressure to rotate the pump. Use proper lockout-tagout. And never use gasoline or other flammable solvents to clean parts – the manual calls that out because a spark from a tool can ignite vapors.

Technical Specifications – Inlet Pressure, Case Pressure, and Viscosity Limits

The technical specifications section gives you the numbers that matter: inlet pressure limits, pressure compensator valve setting, case pressure maximum, hydraulic fluid temperature range 1, and viscosity limits. No manufacturer wants to publish those, but Sauer Danfoss did. For the Series 45, you need to know the minimum inlet pressure to avoid cavitation, and the maximum case pressure to prevent seal failure. The manual also lists the fluid temperature range and viscosity limits – critical for cold starts in San Antonio winters (yes, it gets cold enough to thicken hydraulic oil). This is the data you verify before you spec a replacement pump.

Control Options: PC and LS – How the Manual Explains Them

Two control types are covered: the PC (pressure compensator) and LS (load-sensing). The manual includes cross-section diagrams of both. The PC control operation section explains how the compensator valve limits maximum system pressure. The LS control section walks through how the pump responds to load changes. A typical load-sensing control valve diagram is included. If you are tuning a system that hunts or stalls, the LS control description on the cross-section pump diagram gives you the port locations and spool movements. That is the kind of detail that stops you from replacing a pump that only needs a control adjustment.

Who Needs This Manual? – Home Garage vs. Field Service

DIY mechanics maintaining a skid steer or excavator will find this manual usable. You do not need a hydraulic certification to follow the pictorial circuit diagram and the step-by-step control adjustment procedures. But if you are a professional technician, this manual is the only source for OEM torque specs on the pump mounting bolts and auxiliary pad bolts – not guesses. Shop owners should keep a copy in the tool room so that every tech uses the same data. The manual also covers auxiliary mounting pads, input shafts, and displacement limiter adjustments. That saves a tech from tearing apart a pump that just needs a limiter tweak.

Why OEM Documentation Beats Aftermarket Reprints

Aftermarket manuals often reprint the first printing and miss later corrections. This 2002 Sauer Danfoss service manual is the original OEM document – it includes the safety warnings from the manufacturer, not a generic warning. The copy I have seen uses the actual Sauer-Danfoss symbols from their literature. You get the exact pressure compensator valve setting, not a rounded number. The filtration requirements are listed in microns. Aftermarket manuals skip that. For the Series 45, if you use the wrong viscosity or inlet pressure, you void the warranty and risk pump failure. OEM data prevents that.

Related manuals you might need: Sauer Danfoss Series 90 1998 Service Manual – 88 Pages”>Sauer Danfoss Series 90 1998 Service Manual – 88 Pages offers more coverage for larger pumps. The Sauer Danfoss PVG32 2010 Service Manual – OEM Factory Specs”>Sauer Danfoss PVG32 2010 Service Manual – OEM Factory Specs covers a different product line but same attention to torque data. For the same Series 45 family but a later year, see Sauer Danfoss 45 2005 Service Manual – Factory Specs for Series 45″>Sauer Danfoss 45 2005 Service Manual – Factory Specs for Series 45. External references: the basic principles of hydraulic pumps are explained in Manual Transmission – not directly about pumps, but the mechanical drive concepts apply. Also see the Wikipedia page on Manual Transmission for gear train fundamentals that relate to input shaft configurations.

The manual is 31 pages total – thin enough to print and put in a binder, thick enough to cover everything you need. I would rather have 31 pages of OEM data than 200 pages of generic advice.

Does the manual include torque specs for pump mounting bolts?

Yes. Torque values are listed in the technical specifications section, including mounting flange bolts and auxiliary pad fasteners. You need those to avoid stripping threads in the housing.

What hydraulic fluids are recommended in this manual?

The manual specifies viscosity limits and temperature ranges. It does not list brand names. You match the fluid to the viscosity grade shown – typically ISO 46 or similar depending on ambient temperature. The filtration requirement is given in microns. Use that to select return-line filters. Page 5 of the manual references the fluid section.

Can I use this manual for a Series 45 pump built after 2002?

The manual was published April 2002. Later pumps may have minor design changes. Always verify component part numbers. For post-2002 models, the 2005 edition is more current. But for 2002–2004 pumps, this is the exact factory document.

Is this manual the same as what a dealer would give me?

Yes. This manual was printed by BTI with permission from Sauer Danfoss. It is identical to the OEM service literature for the Series 45 Frame K & L pumps used in BTI equipment. The content matches the original Sauer Danfoss publication at the time of printing.

You are not paying for filler. You are paying for 31 pages of factory engineering data. If you need to rebuild or adjust a Series 45 pump, this manual gives you the control procedures, the safety warnings, and the hydraulic parameters that keep the system alive. Do not trust a third-party photocopy. Access the Factory Manual from AutoRepairManuals and put it on your tablet or bench.