Hydraulic Gear Pumps

Hydraulic Gear Pumps for Mobile and Industrial Machinery

Hydraulic gear pumps are widely used in mobile, agricultural, construction and industrial hydraulic systems. Their compact design, simple construction and reliable operation make them a common choice for applications requiring a constant and dependable supply of hydraulic oil.

At HPM Hydraulic, we offer a wide selection of hydraulic gear pumps for excavators, loaders, tractors, agricultural machinery, industrial equipment and mobile hydraulic systems. Our catalogue includes pumps identified by OEM numbers, manufacturer references, displacement values and technical model codes.

What Is a Hydraulic Gear Pump?

A hydraulic gear pump transfers oil by using rotating gears inside the pump housing. As the gears rotate, hydraulic fluid is carried from the inlet side to the outlet side, creating the flow required by the hydraulic system.

Gear pumps are commonly selected because they offer:

• simple and robust construction,
• compact dimensions,
• reliable operation,
• good efficiency in many applications,
• easy integration into mobile hydraulic systems,
• cost-effective replacement options.

Applications of Hydraulic Gear Pumps

Hydraulic gear pumps are used in a wide range of machinery and equipment, including:

• construction machinery,
• excavators and mini excavators,
• loaders,
• agricultural tractors,
• forklifts,
• municipal machinery,
• industrial equipment,
• hydraulic power units,
• mobile hydraulic systems.

Depending on the machine design, a gear pump can supply hydraulic oil to steering systems, lifting circuits, cylinders, auxiliary equipment and other hydraulic consumers.

How to Select the Correct Hydraulic Gear Pump

Choosing the correct replacement pump requires verification of both hydraulic and mechanical parameters. Pumps that look similar externally may have different displacement, rotation direction, shaft design or mounting configuration.

OEM Number and Pump Reference

The best starting point is the OEM number, manufacturer reference or pump model code. This information may be stamped on the housing, shown on an identification plate or listed in the machine parts catalogue.

Using an exact reference number greatly reduces the risk of selecting an incompatible hydraulic pump.

Pump Displacement

Gear pump displacement is commonly specified in cm³/rev or cc/rev. This value determines the theoretical amount of hydraulic oil displaced during one revolution of the pump shaft.

The replacement pump should match the required displacement of the original hydraulic system.

Direction of Rotation

A hydraulic gear pump may be configured for clockwise or counter-clockwise rotation. Rotation direction must match the machine drive system.

Always confirm the direction when viewing the pump from the correct reference side specified by the manufacturer.

Shaft Type and Dimensions

Check the drive shaft carefully. Important parameters include:

• shaft diameter,
• shaft length,
• keyed or splined design,
• number of splines,
• shaft profile.

Mounting Flange and Ports

The mounting flange, bolt pattern and hydraulic connections must also match the machine.

Verify:

• flange dimensions,
• mounting hole pattern,
• inlet port size,
• outlet port size,
• port position and orientation.

Single, Double and Multiple Gear Pumps

Gear pumps can be supplied as single units or as multi-section assemblies. A double or tandem hydraulic gear pump can supply two separate hydraulic circuits from one drive system.

Multi-section pumps are frequently used in machines where steering, lifting and auxiliary functions require separate hydraulic flows.

When replacing a tandem or multiple pump, all sections must be correctly identified, including displacement, rotation direction, shaft configuration and port arrangement.

Replacement Hydraulic Gear Pumps

A replacement hydraulic gear pump should be selected according to the complete specification of the original component.

Before ordering, prepare:

• machine manufacturer and model,
• pump manufacturer,
• OEM or reference number,
• displacement,
• rotation direction,
• shaft type,
• mounting flange,
• port configuration.

Common Symptoms of Gear Pump Wear

Typical symptoms of a worn hydraulic gear pump may include:

• reduced hydraulic performance,
• slow hydraulic functions,
• increased pump noise,
• loss of performance when oil becomes hot,
• unstable system operation,
• excessive internal leakage,
• hydraulic oil overheating.

Before replacing the pump, the complete hydraulic system should be inspected. Similar symptoms may result from clogged filters, suction-side leaks, relief valve problems or contaminated hydraulic oil.

Hydraulic Gear Pumps from HPM Hydraulic

HPM Hydraulic supplies replacement hydraulic gear pumps for construction, agricultural, mobile and industrial machinery. Pumps can be searched by OEM number, pump reference, machine model or technical specification.

If you are unsure which pump is suitable, provide the machine model, pump identification number and photographs of the existing unit. This information can help identify the correct replacement more accurately.

FAQ – Hydraulic Gear Pumps

What is a hydraulic gear pump used for?

Gear pumps are used to supply hydraulic oil in mobile, agricultural and industrial systems, including steering, lifting, cylinder and auxiliary circuits.

How do I identify a replacement gear pump?

Check the OEM number, displacement, direction of rotation, shaft type, mounting flange and port configuration.

What does cc/rev mean?

CC/rev indicates pump displacement in cubic centimetres per revolution.

Can I replace a gear pump with a higher displacement pump?

Only if the complete hydraulic system is designed for the different flow rate. The replacement should normally match the original specification.

Can a left-hand pump replace a right-hand pump?

Not unless the pump is specifically designed to allow rotation conversion. Always confirm the required rotation direction before installation.

Related Gear Hydraulic Components

Hydraulic gear pumps are often used in systems together with hydraulic gear motors. For pump overhaul and component-level repair, see our hydraulic pump spare parts.

You can also explore our hydraulic hoses for mobile and industrial hydraulic installations.