Talk to an Expert: 586-786-3920 Find Model or Part #

Replacing a Hydraulic Pump: What You Need To Know

Troubleshooting a failing hydraulic pump can be challenging. While knowing common reasons why pumps fail can be helpful, it is easy to impair the system through improper alterations. If you unknowingly make a lousy repair, cavitation can occur. Further, injuries to the person performing the repair can occur if a proper diagnosis is not performed. Here’s what you need to know about hydraulic pump replacement. 

What Are Hydraulic Pumps?

A hydraulic pump is a mechanical actuator that transforms mechanical power into hydraulic energy. A hydraulic function performs two different processes to operate successfully. First, a mechanical action known as a vacuum is created at the pump inlet. This action allows natural pressure to propel fluid from the device’s reservoir to the line to the pump. Second, this action forces this fluid into the pump outlet and moves it further into the system. 

A pump generates either movement or flow using a liquid, it does not create pressure. This flow allows pressure to develop, providing the needed resistance to liquid flow in the machine. For example, the pressure fluid that builds up next to the pump outlet is null if the device is not connected to a load. 

Why Do Hydraulic Pumps Fail?

All hydraulic pumps are defined as either non-positive or positive-displacement units. However, most pumps used in industrial applications in the U.S. are positive-displacement machines. The most common types of hydraulic pumps include: 

  • Rotary pumps
  • Centrifugal pumps
  • Axial pumps
  • Radial pumps
  • Gear pumps
  • Internal gear pumps
  • External gear pumps
  • Piston pumps
  • Vane pumps

There are many reasons why a pump might fail. The unit may be clogged or the mechanisms that force the fluid through the housing may need repairs. The most common reasons for hydraulic pump failure are discussed below. 

What Kills a Hydraulic Pump?

Before identifying the culprit behind the pump failure, it is essential to know the signs that your pump requires repairs. These repairs include: 

  • Increased noise: All mechanical actuators make noise during operation, but hydraulic systems should not produce loud banging or knocking sounds. If you notice a new, unusual sound coming from your device, it may be experiencing cavitation or aeration. 
  • High temperatures: Hydraulic systems should never exceed 82 degrees Celsius. There may be a buildup of residue in the system if you detect a higher-than-average temperature. You need to address the problem quickly, as temperature changes can damage a pump quickly. 
  • Sluggish system: If your system is functioning slower than usual, you may have a problem on your hands. A slow system translates into a loss of pressure, which can indicate a leak is present internally. 

The most common reason for hydraulic pump failure is fluid contamination. Contamination happens when foreign debris enters the internal mechanisms of the system. Systems are only designed to transport hydraulic liquid, and foreign matter in the system can cause damage to the pipes and valves. Other causes of pump failure include: 

Aeration: Aeration occurs when liquid comes under pressure by the pump. If this situation occurs, the fluid can dislodge debris, causing contagion and inevitable pump failure. 

Cavitation: Cavitation is a dangerous situation that takes place when hydraulic liquid does not take up enough space in the pump. Cavitation can occur because of high viscosity or an improperly cut intake line, among other reasons. 

Excessive temperature: An overheated system is a significant indication of an internal issue. Prolonged periods of extreme temperatures can damage components, including the hydraulic seals and valves. 

How To Replace a Pump?

While someone without experience should never perform hydraulic pump replacement, it is vital to know the basic procedure for replacing a failed pump. Here are the basic steps associated with replacing a dysfunctional pump: 

  • Discover the main cause of the pump’s issue.
  • Remove the failing mechanism. 
  • Retract all unit rods.
  • Eliminate all fluid in the tank. 
  • Flush the tank with diesel fluid while the unit is powered on. Wipe away any residue.  
  • Replace the old filter with new filters. 
  • Mount and connect the new pumps. 
  • Put new oil in the tank. Be sure to fill the tank with the required oil grade, as pumps can fail if the wrong oil is administered throughout the system. Pumps require a consistent supply of oil and can fail if the levels drop too low. 
  • To prepare each circuit to flush the valves and lines with new oil, move the control valve handles upward. 
  • Connect all lines to the cylinders and liquid motors. The road end should be left disconnected. Turn on the circuits until the cylinder bottoms out. This process will flush contaminated oil from the cylinder. Repeat this process as many times as necessary. 
    Reconnect lines to the rod end of the cylinder and add more oil as necessary.
  • Change the filter for a final time. 

A licensed, experienced technician should only perform these steps. 

Diverse Hydraulic Pump Options

While there are many hydraulic system options, a pump must be matched to the suitable system for the best performance. Some types are optimal for heavy-duty industrial applications, while others work best in high-heat situations. A few of the most common pumps available include: 

Radial piston pumps: A radial piston pump is a hydraulic unit that works by extending its piston in a radial movement around the drive shaft. These units work in direct contrast to axial piston pumps. Using a radial piston pump in your application comes with many advantages, including high efficiency, optimal reliability, low noise levels and low flow ripples. 

Rotary vane pumps: A rotary vane pump is a positive-displacement device that has a complex configuration. The vanes are fixed to a rotor that alternates inside the cavity. These vanes often have varying lengths to accommodate the walls when the pump rotates. These pumps are not the best option for high-pressure fluids and can be complex to maintain. 

Axial piston pump: This type of pump is classified as a positive-displacement machine that contains many pistons situated around a cylinder block. These pumps can be used alone or with other motors or compressors. The cylinder block works by rotating around its axis by an integral shaft that is aligned with the pumping pistons. 

Other pump types include gear, clutch, dump, screw, diaphragm, progressive cavity, and refuse models. Your requirements should inform the kind of pump you need. 

Reliable Repair Services

If your hydraulic system is failing or you suspect the pump or seals are damaged, Panagon Systems offers reliable repair services. We offer OEM, aftermarket, and new replacement parts. We supply parts that are compatible with Vickers, Caterpillar, and Rexroth pumps. 

While individual replacement parts can be hard to find for many systems, we carry many parts that manufacturers no longer provide. We can help you repair an individual piece or we can provide you with a complete hydraulic pump replacement if necessary. 

The Panagon Difference

Started over 25 years ago, Panagon Systems is a leading supplier of hydraulic parts for many industries, shops, and manufacturers. We are the leading manufacturer of aftermarket hydraulic parts in the U.S. We specialize in supplying clients with many current and discontinued parts. Whether you need an individual component or a complete hydraulic system, we can provide you with the assistance you need. 


Related posts


Your Choice for OEM Quality Replacement Components

Our manufacturing facility houses many CNC machines capable of producing high-quality hydraulic components and replacement parts.

Parts Resources Contact