How does a Hydraulic Pump Work? What are the Types of Hydraulic Pumps?


Hydraulic pumps are vital components in a variety of industrial applications, providing the power needed to move fluids and power machinery. In this comprehensive guide, we’ll explore the types of hydraulic pumps, delve into how they work, and discuss whether it’s better to repair or replace a hydraulic pump.

4 Types of Hydraulic Pumps:

1. Gear Pumps:

1) External Gear Pumps:

This category comprises pumps with two external gears seamlessly meshing together. The synergy of these gears facilitates the efficient transfer of hydraulic fluid.

2) Internal Gear Pumps:

Distinguished by the collaboration of an external and an internal gear, these pumps work in tandem, ensuring reliable fluid displacement.

2. Vane Pumps:

1) Variable Displacement Vane Pumps:

Offering adaptability, these pumps feature adjustable output to cater to varying flow requirements. Their versatility makes them ideal for applications with dynamic hydraulic demands.

2) Fixed Displacement Vane Pumps:

Engineered for a constant fluid flow, these pumps are steadfast and dependable, providing stability in hydraulic systems.

types of hydraulic pump

3. Piston Pumps:

1) Axial Piston Pumps:

Pistons in axial piston pumps move parallel to the pump shaft, ensuring precision and efficiency in fluid transfer. These pumps are valued for their reliability and high performance.

2) Radial Piston Pumps:

Characterized by pistons moving outward from the pump shaft, radial piston pumps excel in robust applications. Their design enables them to handle demanding fluid transfer tasks with ease.

4. Screw Pumps:

1) Single Screw Pumps:

Leveraging a single screw, these pumps are well-suited for applications involving clean or slightly contaminated fluids. Their simplicity and effectiveness make them a popular choice for specific industrial needs.

2) Twin Screw Pumps:

Employing the collaborative effort of two intermeshing screws, twin screw pumps stand out for their enhanced efficiency and capability to handle more challenging fluids.

How Does a Hydraulic Pump Work?

A hydraulic pump is a device specifically designed to manipulate hydraulic oil. Its main function is to convert the mechanical energy generated by the motor or engine into a form of energy called hydraulic energy.

To understand the working principle of a hydraulic pump, you need to master the two basic concepts of flow and pressure. Flow refers to the steady movement of fluid in a hydraulic pump, which is driven and controlled by the pump. Pressure is the force exerted by a fluid on the walls of a system component. The two elements flow and pressure have a direct correlation in the operation of a hydraulic pump. To explain this simply, imagine a water pipe. As water flow increases, the pressure exerted on the inner wall of the hose increases. This principle also applies to hydraulic pumps. An increase in fluid flow naturally increases the pressure within the system.

At the same time, the hydraulic pump can also amplify the energy of the fluid. This energy amplification allows hydraulic systems to perform tasks that require large amounts of force or pressure, such as lifting heavy objects or stopping a speeding vehicle. The creation of this flow and energy amplification distinguishes hydraulic pumps from other types of pumps and makes them an indispensable tool in many modern systems.

However, maintaining a delicate balance between these two factors is crucial. Too much pressure may cause system failure or damage, while too little pressure may not produce enough force for the system to perform its job effectively. Likewise, high flow rates may cause rapid wear on the pump, while low flow rates may not provide adequate power transfer. Therefore, it is important to maintain a good balance between pressure and flow in the hydraulic pump.

How to Repair Hydraulic Pump?

Hydraulic pumps, essential components in hydraulic systems, might require occasional maintenance or repair to ensure optimal performance. Here’s a step-by-step guide on how to repair a hydraulic pump:

1. Identify the Issue:

Diagnostic Inspection: Before beginning any repairs, conduct a thorough inspection to identify the specific problem. Common issues include fluid leaks, unusual noises, or reduced efficiency.

2. Safety First:

Shutdown Equipment: Ensure the hydraulic system is powered down, and any residual pressure is released to guarantee a safe working environment.

3. Disassembly:

Remove Pump: Disconnect the pump from the hydraulic system. This may involve removing bolts, hydraulic lines, or other attachments.

4. Inspect Components:

Check Seals and O-rings: Examine seals and O-rings for wear, cracks, or damage. Replace any components showing signs of deterioration.

5. Clean Internals:

Remove Contaminants: Clean the internal components thoroughly. Remove any contaminants or debris that could compromise pump function.

How does a Hydraulic Pump Work? What are the Types of Hydraulic Pumps?

6. Replace Worn Parts:

Address Wear: If internal components such as bearings, gears, or pistons show signs of wear, replace them with suitable, manufacturer-approved replacements.

7. Seal Replacement:

Seal Integrity: If there are leaks, focus on replacing damaged seals or gaskets. Proper sealing is crucial for preventing fluid leakage.

8. Lubrication:

Apply Lubricant: Ensure all moving parts are properly lubricated. Use the recommended lubricants to maintain smooth operation.

9. Reassembly:

Follow Guidelines: Reassemble the pump following the manufacturer’s guidelines. Pay attention to torque specifications and assembly sequences.

10. Testing:

Bench Test: Before reinstalling the pump in the hydraulic system, conduct a bench test to ensure it operates correctly. Check for leaks, unusual noises, and proper fluid flow.

11. System Integration:

Reconnect: Once the pump passes the bench test, reintegrate it into the hydraulic system. Ensure all connections are secure and aligned.

12. Operational Test:

System Check: Power up the hydraulic system and perform an operational test. Monitor for any issues and address them promptly.


Repairing a hydraulic pump involves a systematic approach, from the identification of issues to thorough testing. Following proper safety protocols and adhering to manufacturer guidelines are crucial for successful repairs, ensuring the hydraulic system operates at peak efficiency. If in doubt, consult with hydraulic system experts or professionals for assistance.

Are Refurbished Hydraulic Pumps a Good Choice?

We often receive inquiries from customers about hydraulic pumps, but they have concerns about the choice between refurbished hydraulic pumps and new hydraulic pumps. Next, we will analyze the advantages and disadvantages of refurbished hydraulic pumps as well as suggestions for selection. I hope it will be helpful to you.

Pros of Refurbished Hydraulic Pumps:

1. Cost-Effective:

Refurbished pumps are generally more budget-friendly than brand-new alternatives. This can be particularly appealing for cost-conscious buyers.

2. Environmentally Friendly:

Opting for refurbished pumps contributes to environmental sustainability by extending the lifespan of existing equipment, and reducing the need for new manufacturing.

3. Availability:

Refurbished pumps offer a solution when specific models or older versions are no longer in production. They can provide access to otherwise hard-to-find components.

4. Quality Assurance:

Reputable refurbishing services conduct thorough inspections, replacing worn components and ensuring proper functionality. This attention to detail can result in a reliable product.

Cons of Refurbished Hydraulic Pumps:

1. Variable Quality:

The quality of refurbished pumps can vary based on the refurbishing process and the expertise of the service provider. It’s essential to choose a reputable supplier.

2. Limited Warranty:

Refurbished pumps often come with a limited warranty compared to new pumps. Buyers should carefully review warranty terms and conditions.

3. Potential Hidden Issues:

Despite refurbishment efforts, there’s a risk of hidden issues that may not become apparent until the pump is in use. Thorough testing before integration is crucial.

Some Tips for Decision-Making:

1. Supplier Reputation:

Choose a refurbishing service with a proven track record and positive customer reviews. A reputable supplier is more likely to provide quality refurbished pumps.

2. Application Compatibility:

Ensure the refurbished pump meets the specific requirements of your application. Compatibility is crucial for optimal performance.


Q1. How to Clean a Hydraulic Ram Pump?

A: Periodically flush the system to remove any sediment or debris that may affect the pump’s efficiency.


Q2. How to Adjust the Stroke Length?

A: Most ram pumps come with adjustable settings. Follow the manufacturer’s guidelines to modify the stroke length for optimal performance.


Q3. Can a Hydraulic Ram Pump Lift Water Uphill?

A: Yes, hydraulic ram pumps are capable of lifting water uphill to a certain height, making them versatile for various topographies.


Q4. How Much Water Flow is Needed?

A: The water flow required depends on the specific ram pump model. Check the manufacturer’s recommendations for the optimal flow rate.

Q5.Is Pressure Adjustment Necessary for New Hydraulic Systems?

A: Yes, even new systems may require adjustments to ensure they operate within specified parameters.


Q6. Are There Hydraulic Pumps with Automatic Pressure Adjustment?

A: Some advanced hydraulic systems may have automatic pressure control features. Refer to the system specifications for details.

More Knowledge About Hydraulic Pump:

How To Bleed Air From Excavator Hydraulic Cylinder
How To Solve Hydraulic Pump Overheating Problem

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *