what causes hydraulic pump failure brands

The pump is the most expensive and critical component in any hydraulic system—it works by first creating a vacuum at the pump inlet, which generates atmospheric pressure. Liquid from the reservoir tank is then propelled through the inlet line to the pump, past a hydraulic filter or strainer, and into the hydraulic system. On a macro-level, the mechanical energy of the pump’s gears is transferred through fluid “flow” and used to power the attached hydraulic machinery.

Although hydraulic systems can be used in many everyday objects, they’re usually best suited for products that require high-power density or systems with changing load requirements. This simple yet elegant design offers exceptional consistency and speed compared to other driving mechanisms. Hydraulic systems are widely used across industries because they are reliable, easy to maintain, long-lasting, and safe. But despite their many advantages, hydraulic systems still require some degree of maintenance. The following guide explains what can make a hydraulic pump fail, as well as tips for extending its useful lifespan as much as possible.

Fluid contamination is the leading cause of pump failure and usually happens when particulates circulate through the system via a breather valve or cylinder rod, or as a result of repairs, welding slag, sealant, or refilling. Once contaminants enter the system, they can degrade parts, create buildup, change the fluid’s physical and chemical properties, corrode equipment, and lower the system’s overall efficiency.

Hydraulic pumps are designed to work within a specific pressure range. If pressures exceed the pump’s rating, it will likely overburden the pump, cause damage, and eventually halt operations completely. If the pressure changes are extreme, it could even cause an explosion.

Joints and shafts must be completely sealed for the hydraulic pump to work properly. If air gets trapped inside the system, bubbles can cause pressure and temperature fluctuations, which eventually will cause the pump to break down. Usually the first sign there’s air in the pump is a high-pitched whine.

Cavitation occurs when the pump speed is inconsistent, creating air bubbles that rapidly form and then collapse. When this happens, the pump won’t completely fill with fluid, which destabilizes pressure in the system and produces the same type of high-pitched squeal as pump aeration. A blocked pipe, clogged filter, or poor system design can all cause cavitation.

Hydraulic systems need high-quality cooling and lubrication oil with the right mineral content and viscosity. Purity is particularly important for high-pressure systems that operate with larger loads.

The best way to prevent hydraulic pump failure is to inspect and maintain your hydraulic system. Hydraulic filters and strainers will help you avoid fluid contamination, which in turn will stabilize the temperature and pressure inside the system. Filters remove particulates that are smaller than 50 microns, and strainers work tangentially to remove contaminants larger than 50 microns. Various options are available for both filters and strainers using different ratings, mesh sizes, and materials.

After they’re installed, filters and strainers need to be routinely checked and cleaned. Operators should familiarize themselves with their hydraulic system to identify any aberrant conditions as soon as possible, if problems should arise. If you maintain your hydraulic system, it will work more efficiently, necessitate fewer repairs, require less downtime, and last as long as possible.

With over 60 years of experience manufacturing high-quality suction filters, suction strainers, gauges, and diffusers for hydraulic systems, the experts at DOMS Incorporated have the expertise to keep your operation in peak condition. We’ve worked closely with organizations from many industries, including construction, forestry, mining, energy development, industrial manufacturing, aircraft equipment manufacturing, plant processing, and more.

Hydraulic pumps are at the core of many essential factory operations. Unfortunately, there are numerous pitfalls to plan for, mitigate, and overcome to keep them running. Keeping up on routine maintenance is important, but the best way factory techs can avail themselves of costly, frustrating breakdowns is to understand the various catalysts for hydraulic pump failure.

The simplest way to identify the cause of pump failure is to thoroughly inspect and dissect the aftermath of the problem. In most cases, the cause of failure will be evident by the nature of the catalyst(s). Here are eight of the most common problems, some of their defining features, and how they ultimately come to fruition.

1. Fluid contamination is one of the biggest causes of hydraulic pump damage and involves debris mixing with the liquid. This debris causes friction, leading to extenuated wear on the pump itself. The result is inefficiency, culminating in malfunction.

2. Fluid viscosity issues occur when the hydraulic fluid within a pump breaks down over time. Viscosity that’s too high leads to cavitation (another catalyst for damage). Subsequently, if a tech changes and replaces fluid with a viscosity that’s too low, heat and friction become concerns.

3. Over-pressurization occurs because of excessive load on the pump itself, resulting in red-line operation that’s both unsafe and damaging. Hydraulic pumps operating under high duress for extended periods of time will likely experience component wear and premature failure, usually in spectacular fashion.

4. Excess heat can be a product of poor fluid viscosity or environmental factors. This issue is rarely a singular catalyst for pump breakdown, but it exacerbates other factors or masks other issues, such as fluid contamination.

5. Implosion invariably results in extreme failure for hydraulic pumps and is a major safety hazard. Implosion occurs when air bubbles within a hydraulic pump collapse, causing an overload of pressure to the pump that generates an intense shock.

6. Aeration occurs when hydraulic fluid traps air bubbles. The pump subjects the bubbles to pressure, causing high heat and over-pressurization when the bubbles collapse. Aeration at extreme levels leads to implosion.

7. Pump aeration pertains to air not in the hydraulic fluid, but air introduced through unsealed joints or shafts. This air quickly causes pressure instability affecting crucial parts of the pump. This can quickly lead to breakdowns — generally marked by a whine or other high-pitched sound.

8. Cavitation is a symptom of uncontrolled pump speeds, which fail to allow hydraulic fluid to completely fill the pump. It results in destabilized pressure, heat, and excess wear. Cavitation is often marked by the same type of whine or squeal as pump aeration.

Because the factors causing each of these problems differ in nature, it’s best to fully evaluate a damaged hydraulic pump to determine if more than one issue is responsible.

Maintenance is the best approach for ensuring safe, efficient hydraulic pump function. But routine service is just the start. Identifying common issues plaguing your hydraulic pumps will lead to a better quality of targeted maintenance — for example, if you pinpoint a heat issue related to viscosity, that issue may be resolved by opting for a different fluid weight.

Every piece of information learned about your pumps can translate into better care, leading to longer uptimes, fewer issues, and fundamentally better maintenance.

Having trouble identifying the catalysts for your hydraulic pump’s issues? Let the professionals at Global Electronic Services take a look! Contact us for all your industrial electronic, servo motor, AC and DC motor, hydraulic, and pneumatic needs — and don’t forget to like and follow us on Facebook!

When a reliable hydraulic system suddenly starts exhibiting problems, one of the first types of components most technicians assume may need to be replaced are hydraulic pumps, yet the pump should be the last component evaluated since it is often very time-consuming to replace.

There are all sorts of “warning” symptoms a hydraulic system will exhibit long before pump failure. Some of the most common types are changes in the sounds the system makes while it is in operation. If the system suddenly starts sounding different from how it has before, this could indicate various types of problems.

Another thing to check if you notice the system is not working correctly is to verify the pump is turning. Some systems are designed so that you have to manually engage or switch the pump on. You would be surprised by how many system problems are due to the pump not being turned on!

The last thing to check before getting into troubleshooting the pump is the hydraulic fluid level. If the fluid level is too low, it will allow air into the system and cause operational problems. If you discover air in the system, you will need to remove it first to avoid pump failure.

Aeration occurs when air is introduced into the hydraulic system. This can be due to defective seals, through low tank fluid level allowing air into the pump inlet line, damaged inlet hoses and connections. It is easy to check to find out if there is air in the system as the fluid returning to tank will be foamy and the oil in the tank full of bubbles.

Operating the system when air is present may result in the pump being unable to reach the pressures required to operate the system. A by-product of this problem is the generation of excessive heat. Excessive heat is of course another reason in itself for pump failure, in this case secondary to aeration but demonstrates how the primary cause can set off a vicious circle, in this case aeration, leading to excessive heat, leading to lack of lubrication, leading to contamination issues, possible partial or full bearing seizure before complete pump failure.

The opposite of aeration is cavitation. Instead of air being added to the fluid, it is removed very rapidly. Cavitation is where air bubbles form quickly and collapse inward on each other within the fluid. This occurs due to a vacuum at the pump inlet as a result of an insufficient fluid supply. As in excess of 10% by volume of hydraulic fluid is dissolved air when there is an excessive vacuum at the pump inlet it is this air that is being drawn out of the oil.

The effects of cavitation can be seen around the internal pump inlet surfaces as the air is drawn out the oil it causes the removal of tiny amounts of material from the internal pump surfaces on the inlet side. This is always particularly evident in aluminum gear pumps as it leaves a slightly pock marked or frosty looking surfaces on the bearing blocks and inside of the gear housing on the inlet side.

Every hydraulic pump has a maximum design pressure level. If you attempt to operate the pump at a higher pressure than it was designed for, it will cause premature pump failure. The pump simply cannot handle the excessive pressure.

Contaminants are one of the biggest reasons for hydraulic pump replacement. Contaminants can enter into the hydraulic system through a variety of entry points. One of the most common ones is through the hydraulic fluid reservoir.

As contaminant levels grow, they can get stuck in between key surfaces such as between gear end faces and bearing block or pressure plate or between piston barrel and valve plate in a piston pump. This then leads to further wear and the generation of more contaminant and heat. The more contaminant induced wear there is to these surfaces the larger the gap becomes between these critical surfaces leading to loss of pressure capability, overheating and failure.

The viscosity of the hydraulic fluid moving through the system could lead to premature pump failure if it is not properly maintained. Having a fluid of a higher viscosity level than specified for the pump can result in cavitation within the hydraulic pump.

On the other hand, when fluid viscosity is too low, it can lead to excessive leakage between critical surfaces leading to an increase in heat generation. As such, the fluid can become too hot, overheating the entire system, and ultimately causing premature pump failure.

Extreme heat is often caused as a byproduct of other hydraulic system problems. If you notice your system seems to be operating at a higher temperature than it normally does, take it as a warning sign that something is wrong. Continuing to operate the system can lead to more costly repairs.

Excessive heat levels not only cause parts and components to fail but also can damage drive shafts, housings, and other metal components. Additionally, damaged parts and components may not properly seal leading to fluid leaks. Furthermore, inside pumps, misalignment of moving parts could occur, causing internal damages that introduce contaminants into the system.

Many types of hydraulic pump system failures could easily be avoided with regular pump maintenance. Regular maintenance requires checking and inspecting the entire hydraulic system prior to using it. Some of the more common things you should do include:

Another vital part of maintenance is replacing worn out hoses, valves, and related parts and components when they show signs they need to be replaced. It is better to replace hydraulic system parts and components before they fail. Doing so will result in low overall maintenance and repair costs. When replacing components always make certain they are clean of dust and dirt before fitting to avoid unwanted contamination entering the system.

Furthermore, hydraulic fluid should be changed periodically as it starts to slowly break down from extended use. Your objective is to ensure the fluid provides the right viscosity level required for your hydraulic operations. Always flush the system and replace the hydraulic fluid when replacing a pump or motor and be especially vigilant in removing contaminant from every nook and cranny of the system when component failure has been due to contamination damage and the source of contamination has been ascertained.

For further help troubleshooting hydraulic pump system failures, as well as all of your hydraulic system motors, pumps, parts, and component needs, please contact White House Products, Ltd. at +44 (0) 1475 742500 today!

Water mixing in with the hydraulic fluid is bad news for the hydraulic pump. When too much water is present in the hydraulic fluid, the internal components may start to corrode.In addition to its corrosion-causing qualities, water is also problematic because it could freeze inside the pump.

The hydraulic fluid present inside the pump can also be problematic even if it doesn’t mix with water.If some small particles fall into the liquid, it’s possible that they could deal damage to the inside of the pump. You must also check if the fluid level is correct or else that could alter the performance of the pump.Lastly, the viscosity of the hydraulic fluid must be just right to keep the pump from sustaining damage. Make it a habit to routinely check the viscosity of the hydraulic pump to see that it has not degraded just yet.

Heat can act as a kind of amplifier of other hydraulic pump-related issues. The heat itself can be a byproduct of other issues affecting the hydraulic pump so be sure to take note of it.

Because hydraulic pumps need the right pressure levels to function, anything that affects it can be disruptive or even damaging. Some of the joints and shafts of hydraulic pumps may spring leaks as they age causing holes to open up. If too much air gets inside the pump via the holes, it may not work as intended.

Cavitation refers to the formation of small vapor-filled bubbles in areas within the pump where the pressure is low. Once those bubbles are exposed to high pressure, they may burst and start to damage the pump.

Hydraulic pumps are essential components in countless different types of applications. In many cases, they’re expected to run around the clock, and any downtime can grind operations to a halt.

Hydraulic pump failure has a number of different internal and external causes, and understanding what those are can help prevent issues in the future. Poor maintenance, extreme operating conditions, and problems with other components can all contribute to failure and can all be carefully planned for and monitored to prevent any issues.

Ideally, you’ll discover that there’s an issue with the pump before a complete failure. Identifying any problems earlier will give you more time to plan a response instead of scrambling when operations shut down unexpectedly. Minor fixes can even be incorporated into your

Loud noises are going to be one of the most serious indicators of hydraulic pump failure. While your pumps will be making noise during regular operation, various faults can cause a loud knocking or banging. If you start to hear these noises from your pump, failure is likely right around the corner. Consider it your pump crying out for help.

Temperature is another key factor to watch for hydraulic pumps. Most hydraulic systems recommend operating at no more than 180 degrees Fahrenheit or 82 degrees Celsius, and temperatures climbing higher than that are a clear indication that something is wrong.

Continuing to use the system with a partially damaged pump will only speed up the complete failure of the hydraulic pump, so it’s best to address these issues as soon as you notice any signs.

Many different factors can lead to hydraulic pump failure. No matter what the specific cause, it’s important to remember that pump components likely haven’t broken for no reason at all. Pump failure is a sign that something must be wrong somewhere in the system, with the effects ultimately leading to the failure of the pump.

Cavitation is a likely cause of loud banging noises coming from the pump. Dissolved gasses within the oil can react to pressure differences by coming out of the oil and then being collapsed by the high pressure.

Aeration can have similar effects. This issue occurs when external air enters the system through leaks, loose connections, or other problem areas. It generally creates a much more mild knocking but is still causing damage that eventually leads to hydraulic pump failure.

The look of the hydraulic oil itself can give an indication of water contamination by appearing hazier and less clear than usual. Water contamination will wear down hydraulic components and can cause oxidation over time as well.

Significant overheating can lead to oxidation of the hydraulic fluid, which causes the fluid to become thicker. This thickening can limit flow through the system, further reducing heat dissipation and potentially causing even more severe overheating.

Low temperatures can also cause problems. The hydraulic fluid can only effectively flow once it approaches operating temperatures. Pump failure can be caused by increasing the load before the operating temperature is met, which is more common with lower ambient temperatures.

Many different mistakes can lead to premature or even immediate hydraulic pump failure. A faulty installation could result in instantaneous and catastrophic damage to the system or gradual wear that isn’t discovered for years. Poorly fitted pipes and other pump components could contribute to leaks.

An incorrect combination of different parts can cause hydraulic pump failure as well. A motor might have excessive drive speed for a pump, or various types of control equipment can be incompatible. In any case, these issues can lead to increased wear or even immediate failure.

Failing to implement effective maintenance will also lead to premature failure. If the proper maintenance schedule isn’t followed, excessive wear can develop. This risk is true for both the pump and other system components that can affect the pump if not properly maintained.

Even if a hydraulic pump is replaced or repaired, the issue is likely to occur again if the root cause isn’t identified and resolved. This diagnostic could mean evaluating the entire system to find out just what went wrong. There could be other components that allow for fluid leaks or air and water to enter the system.

To prevent future hydraulic pump failure, you should ensure that the system follows all relevant specifications. Operating outside of these specifications could cause damage to the pump and other components that eventually lead to hydraulic pump failure.

After a pump failure, a professional inspection of the entire system may be in order. Avoiding this precaution could lead to another failure shortly or even more excessive damage to your hydraulic systems.

Many hydraulic components are relatively quick and inexpensive replacements, and avoiding necessary repairs can only lead to serious issues down the line.

The team at MAC Hydraulics can provide all of the services you need for your hydraulic system, including professional troubleshooting. We offer replacement hydraulic pumps, repair pumps, and cover maintenance to prevent unexpected hydraulic pump failure.

For fast and effective troubleshooting, you can reach out to us as soon as you notice issues like increased noise, oil leaks, loss of power, limited flow, or overheating. Our team will determine the root cause of the problems you’re experiencing with your pump to ensure that they won’t happen again.

That also includes effective resealing to help you get the most out of your existing components, instead of having to replace them before their time. Our experienced team can go over your options and find the best solution for your hydraulic systems today.

You rely on your hydraulic systems every day and can’t afford to let hydraulic pump failure grind operations to a halt. Whether the issue is air or water contamination, overheating, over-pressurization, human error, or anything else, the end result will be the same when your pump quits.

Every component within a hydraulic setup will affect the overall system. Hydraulic pump failures can indicate further issues with other parts of the system. Looking into exactly what the real cause is can help prevent additional failures in the future.

Whenever your system suffers from pump failure, it’s best to go with trusted professionals for the replacement or repair you need to get running again. An experienced team can ensure that you have the right pump for your system and that the installation is carried out safely and reliably.

Your hydraulic pump is the heart of your machine, pumping fluid through your hydraulic system. Pump failures mean downtime and expensive repairs, but the sooner you recognize pump problems developing the easier it is to fix. In this Shop Talk blog post, we are going to discuss, we are going to discuss the most common signs and causes of hydraulic pump failure.

If you notice any of these symptoms, keep in mind that it doesn’t necessarily mean that the pump is going out -- but it means something in your hydraulic system is about to! Check out this video below for an example of what can happen to a Bobcat pump.

Sadly, no pump will last forever because they suffer wear and tear from regular use. Bearings and seals will eventually need to be replaced, and if those replacements are put off then your pump may suffer even worse damage. If you suspect your hydraulic pump needs a tune up, then don’t hesitate to see after it -- it will extend the life of your pump and increase your machine’s overall productivity.

is your partner in providing new or remanufactured final drive hydraulic motors from a single mini-excavator to a fleet of heavy equipment. Call today so we can find the right final drive or hydraulic component for you, or check out our online store to.

When a hydraulic system fails, finding the source of the problem can be a challenge. Though hydraulic systems primarily consist of a sump, motor, pump, valves, actuators and hydraulic fluid, any of these parts could be the source of failure. That"s not to mention the additional potential for failure through human error and faulty maintenance practices. If your system fails, you need to know why it fails, how to find the failure and how to keep it running smoothly in the future, all while keeping personnel safe.

It"s often easy to tell when a hydraulic system fails — symptoms can include high temperatures, low pressure readings and slow or erratic operation are glaring problems. But what are the most common causes of hydraulic systems failures? We can trace most hydraulic issues back to a few common causes, listed below.

Air and water contamination are the leading causes of hydraulic failure, accounting for 80 to 90% of hydraulic failures. Faulty pumps, system breaches or temperature issues often cause both types of contamination.

Air contamination is the entrance of air into a hydraulic system and consists of two types — aeration and cavitation. Both can cause severe damage to the hydraulic system over time by wearing down the pump and surrounding components, contaminating hydraulic fluids and even overheating the system. Although we are not pump manufacturers, we know it is essential to be aware of these types of contamination and how to identify their symptoms.

Cavitation:Hydraulic oil consists of about 9% dissolved air, which the pump can pull out and implode, causing pump problems and damage to the pump and to other components in a hydraulic system over time. You can identify this problem if your hydraulic pump is making a whining noise.

Aeration:Aeration occurs when air enters the pump cavity from an outside source. Usually, loose connections or leaks in the system cause this issue. Aeration also creates a sound when the pump is running, which sounds like knocking.

Water contamination is also a common problem in hydraulic systems, often caused by system leaks or condensation due to temperature changes. Water can degrade hydraulic components over time through oxidation and freeze damage. A milky appearance in hydraulic fluid can help you identify water contamination.

Fluid oxidization: Extreme heat can cause hydraulic fluid to oxidize and thicken. This fluid thickening can cause buildups in the system that restrict flow, but can also further reduce the ability of the system to dissipate heat.

Fluid thickening:Low temperatures increase the viscosity of hydraulic oil, making it harder for the oil to reach the pump. Putting systems under load before the oil reaches 70 degrees or more can damage the system through cavitation.

Fluid levels and quality can affect hydraulic system performance. Low fluid levels and inappropriate filtration can result in air contamination, while fluid contamination can cause temperature problems. Leaks can further exacerbate both issues.

Using the correct type of fluid is also essential, as certain hydraulic oils are compatible with specific applications. There are even oil options that offer higher resistance to temperature-related problems. Some oils even offer anti-wear and anti-foam additives to help prevent against wear and air contamination, respectively.

Human error is the base cause of many hydraulic system problems. Some of the most common errors that may result in your hydraulic pump not building pressure include the following.

Faulty installations: Improper installation of any component in a hydraulic system can result in severe errors. For example, the pump shaft may be rotating in the wrong direction, negatively affecting pressure buildup, or pipes may be incorrectly fitted, resulting in leaks.

Incompatible parts: An inexperienced installer may put mismatched components together, resulting in functional failures. For example, a pump may have a motor that runs beyond its maximum drive speed.

Improper maintenance or usage:Using systems outside their operational capabilities or failing to perform regular maintenance are some of the most common causes of hydraulic system damage, but are easy to rectify through updated maintenance policies and training.

The sources of system failures can be tricky to identify, but some hydraulic troubleshooting steps can help narrow down the options. So how do you troubleshoot a hydraulic system? Here are some of the fundamentals.

Check the pump: Take the pump assembly apart and assess all parts to ensure that they are functional and installed correctly. The most common problem areas include the pump shaft, coupling and filter.

Check the fluids:Check the level, color and viscosity of the hydraulic oil to ensure it meets specifications and has not become contaminated. Low hydraulic fluid symptoms include pressure or power loss. When in doubt, drain and replace the fluids.

Check the seals: Look for evidence of any fluid leakage around your hydraulic system"s seals, especially the shaft seal. Leakage can indicate worn-out or blown seals that can cause malfunctions with pumps, motors and control valves.

Check the filters: Ensure filters are clear of plugs and blockages. Common clogged hydraulic filter symptoms include sluggish operation and noisy operation.

Run the system: When you have completed all these essential checks, turn on the system and monitor it for pressure and temperature fluctuations, as well as abnormal sounds. If all seems well, check your pressure sensor for potential failure.

Hydraulic system issues are inevitable at some point. However, simple steps can help you avoid these issues and increase the longevity of your hydraulic system. On top of effective troubleshooting, you can prevent hydraulic system failure by taking the following steps.

Follow specifications: We can trace the most common hydraulic system issues back to fundamental system problems like incompatible or improperly installed parts. For this reason, it"s essential to always double-check specifications to ensure your purchased parts can work together seamlessly.

Consult with professionals: When purchasing new equipment, consult with industry peers and professionals to discover what they recommend. While manufacturers can tell you how a product should work, industry professionals can provide concrete examples of how well the equipment works for their industry.

On top of these steps, look into hydraulic system products that are specifically designed to help prevent failures. One such product is Bear-Loc® by York Precision. This innovative locking actuator is a safe, reliable feature for hydraulic components, automatically locking when sleeve pressure is relieved, preventing movement if a hydraulic system fails. This way, your can protect your personnel from injuries related to hydraulic failures. Even better, York Precision offers in-house design, engineering expertise and machining and manufacturing capabilities to produce a hydraulic locking device that meets your exact specifications.

Regularly review hydraulic system maintenance, always following manufacturer recommendations and industry best practices. Also, consider the storage condition, external influences, working pressure and usage frequency of your system to tailor your maintenance schedule and procedures.

Daily tasks:Take care of a few simple daily checks to avoid issues. For example, personnel should check the oil levels, hoses and connections and listen to the pump for abnormal sounds.

Routine tasks:Plan and execute a weekly and monthly maintenance routine, checking for the most common failure sources given your system"s working conditions. These should include components, filters and the condition of the oil.

Be mindful of location:Do not stand at endpoints while working on hydraulic systems. This safety measure can help prevent loss of limb and life, as there is a lot of pressure built up in these areas that can release and result in life-threatening situations.

The best safety measures, however, are to perform excellent maintenance and use high-quality parts. If you"re looking for a quality hydraulic component manufacturer, York Precision Machining & Hydraulics can help.

The hydraulic pumps on construction equipment are critical components of the machines and even though they are often designed to work under vigorous and intense conditions, no pump will last forever. Discovering a problematic pump can be complicated as the effects might seem to originate in other connected parts, and, if failures are gradual, the cascading effects of a pump failure can spread throughout a machine.

To help in your diagnosis — and with a small dash of preventive maintenance — we’ve put together this basic, short list of common pump problems and their causes.

Not every hydraulic pump on a machine is simple to inspect, but this Volvo main hydraulic pump on a EC220B-LC excavator sits behind a quick access door so an operator can check it often.

A failing hydraulic pump can be a long and subtle process, a sudden and catastrophic calamity, and all shades in-between, but often a perceptive operator will notice the signs of a pump failure in advance. It might take a few minutes of stopping and inspecting, but knowing what to watch for and taking the time to inspect your hydraulic pumps can often pay off in the long run and lead to fast and simple fixes, instead of prolonged and labor-intensive downtimes.

A hydraulic pump is often secured behind a door or guard or integrated deeply into the body of a machine, but taking the time to inspect the pump for the presence of oil (or oil and dirt clumping) can lead to the early discovery of problems. If the issue is simply a loose connection, a quick tightening can often stop a small issue from growing.

Since a hydraulic pump has both seals to prevent fluid from exiting the pump and also fluid from prematurely entering from one chamber to the next, failing seals can be both internal and external. Spotting an exterior leak is, of course, simpler, but being aware of where seals exist inside the pump can also help you diagnose a failing internal seal.

The most frequently noticed indication of a failing pump is often the start of a new sound coming from the hydraulic pump. An experienced operator will often immediately know and recognize a pump that is indicating issues through sounds, but for many it can be harder to pinpoint.

A problem with a pump can cause it to simply become louder in its operations, develop a whining sound, or even create a knocking sound. The sounds can indicate a number of problems, but often the cause is either cavitation or aeration in the pump.

Over long spans of work and under intense conditions, a hydraulic pump will often heat up, but excessive heating is often a sign of internal issues in the hydraulic pump. Checking a hydraulic pump for excess heat should always be done with safety in mind and with a secure machine and proper protective equipment. Periodically ensuring a hydraulic pump isn’t overheating allows an operator to discover if the pump is under undue strain and on a path to failure.

Overheating in a hydraulic pump can also cause fluid to thin, cause internal components to more rapidly degrade, and introduce dangerous working conditions to the machine. Overheating in a pump is both a sign of current trouble and a cause of other growing problems.

Unexpected and non-fluid movement of parts can be caused by issues with the hydraulic pump, but since the culprit can be a number of other parts in the system, diagnosing pump issues from these movements isn’t always simple. Still, if you do notice non-uniform movements in your machine, taking time to rule out the hydraulic pump is important.

A main hydraulic pump, like this one from a Komatsu PC400LC-6 excavator, comes with a working life and will need to be replaced or rebuilt at some time. This one is fresh from an H&R Recon and Rebuild shop and is headed to a customer.

Knowing some of the common causes of hydraulic pump failures is a proven way of proactively discovering developing issues and correcting them before they become disastrous to the pump and the machine.

The internals of a hydraulic pump are designed to work with fluid that meets exacting specifications. When hydraulic fluid is contaminated it can lead to issues developing in the pump, force the pump to work harder, and cause the pump to work erratically. One common culprit for contamination is water, and it can quickly lead to increased corrosion, changes in viscosity that lead to inefficiencies, and the inability to properly regulate heat in the pump.

Other debris, either introduced from outside or from the degradation of internal elements, can also lead to issues in the pump and signal failing seals or other parts.

A hydraulic pump is often containing a high level of pressure and as this pressure exerts force on seals in the pump, the seals can begin to leak or fail. Even minor leaks in seals can lead to loss of fluid and create issues in the system. Leaks can be both external and internal. For an internal leak, fluid will move from one part of the pump to another in unintended ways and force inefficiencies into the pump as it has to work harder to compensate.

While many hydraulic pumps are built to stand up to tough and continuous working conditions, every hydraulic pump is designed with an upper limit. Every time a hydraulic pump is subjected to overpressuring and overloading beyond what the manufacturer has specified, the pump is more prone to damage.

All hydraulic oil has a defined amount of air dissolved in it, but increases to this amount can lead to inefficiencies in the pump and force the pump to work harder or erratically. An increase in air can also happen inside the pump and create similar problems. Even though the pump and hydraulic system have mechanisms in place to regulate air in the system, if excess air is introduced the system should be returned to a balanced system before prolonged use of the pump.

The hydraulic system on a construction equipment machine is designed to work within defined parameters. Operating a machine with too little oil or too much oil for even the briefest amount of time can cause the pump to overwork, lead to increases in working temperatures, or create conditions for non-uniform movement. The exact type of oil used — matched to the machine and the working environment — can also impact how the hydraulic pump operates.

The operator’s guide of your machine will define the hydraulic oil change schedule and adhering to that schedule can extend the life of your hydraulic pump. When oil is changed, take time to examine the spent oil for signs of debris

Keeping a pump on a hard-working machine looking new every day is nearly impossible, but routinely peeling back dirt, grime, and oil can help catch issues early.

No one wants to take a machine out of work for cleaning, but keeping the machine clean and ensuring pumps are not covered in mud, dirt, or other debris can allow them to be inspected more easily and avoid contamination and overheating.

The hydraulic hoses connected to a hydraulic pump can wear out over time and ensuring they are well-maintained can help you avoid the introduction of debris and even catastrophic issues in the case of sudden failures.

If a hydraulic pump fails on your machine, taking time to ensure you properly diagnose why and how the failure occurred will help you avoid repeating the failure with your replacement pump. Even if the pump failed simply from prolonged use and age, taking time to confirm that can lead to insights about how to extend the life of the next pump.

A hydraulic pump on an excavator, wheel loader, dozer, or articulated truck can be an often ignored component of the machine — until it starts to act up and cause issues. If problems have brought a pump to the forefront of your mind, hopefully, this short guide has helped simplify your pump problem solving.

If you find yourself in need of a replacement hydraulic pump, our Parts Specialists are always here to help. As a supplier of new, used, and rebuilt hydraulic pumps and with our deep inventory of parts, our Parts Specialists can often find the perfect solution to get a customer back up and running quickly. Simplify your search and give them a call.

Don"t see what you are looking for? With access to specialized search tools and our extensive vendor network, our parts specialists are here to search for you and to connect you to your parts, fast and simple.

The look and design of a hydraulic pump is customized to fit the machine and the available space. This main hydraulic pump is freshly reconditioned from a Kobelco SK160LC-VI excavator.

Hydraulic pumps come in a wide range of shapes and sizes. This large Volvo main hydraulic pump requires assistive overhead cranes and forklifts to move around the warehouse.

A hydraulic pump failure can be caused by a number of factors. There are several different types of pumps available on the market, and each can have its own specific failure mode. Of course, certain failure modes are common to all types of pumps. Some of these failures can be caused by poor system design, using low-quality fluids and/or poor contamination control.

The best way to prevent future failures is to ensure that you are using quality hydraulic fluids. Keep in mind that the fluid is the single most important component of a hydraulic system, so always use high-quality hydraulic fluids with the correct viscosity for critical equipment.

Hydraulic fluids should also be kept clean, cool and dry. This is highly important to their performance. One of the ways you can do this is through quality filtration. Filters should be selected only if they achieve the target cleanliness levels that have been set for the fluid in the system. Also, use quality filters in locations that assure the required protection and upgrade the filters when necessary.

Another option for keeping hydraulic fluids clean is oil regeneration technology. Using a system that is able to separate and remove particles down to the nano scale can make a major difference in the service life of the hydraulic fluid while also extending the life of machines.

In addition, consider the possibility of using offline filters, because the cost of removing dirt is often much less in an offline mode than trying to do everything in a pressure-line filter location on the hydraulic system.

It is estimated that between 70 to 80 percent of hydraulic system failures are from contamination, with particle contamination making up the largest portion. Therefore, it is best practice to regularly perform oil analysis with particle counts.

Remember, the hydraulic pump is generally the most expensive component on a hydraulic system. It has the highest reliability risk, the highest contaminant sensitivity risk and the ability to cause chain-reaction failures. In other words, when the pump starts to fail, it starts to kick out debris into a debris field downstream of the pump. If there is not a good filter downstream, this debris moves on to other components like valves and actuators, and can lead to damage in those components as well.

Be wary of quick-fix solutions like switching to costly synthetics. Instead, provide solutions to the problems that exist and tackle potential future problems proactively. It is critical to set the proper cleanliness and dryness targets and to develop contamination control procedures that will allow you to meet those targets. By doing so, you should greatly reduce and possibly eliminate your pump failures.

Check that the pump shaft is rotating. Even though coupling guards and C-face mounts can make this difficult to confirm, it is important to establish if your pump shaft is rotating. If it isn’t, this could be an indication of a more severe issue, and this should be investigated immediately.

Check the oil level. This one tends to be the more obvious check, as it is often one of the only factors inspected before the pump is changed. The oil level should be three inches above the pump suction. Otherwise, a vortex can form in the reservoir, allowing air into the pump.

What does the pump sound like when it is operating normally? Vane pumps generally are quieter than piston and gear pumps. If the pump has a high-pitched whining sound, it most likely is cavitating. If it has a knocking sound, like marbles rattling around, then aeration is the likely cause.

Cavitation is the formation and collapse of air cavities in the liquid. When the pump cannot get the total volume of oil it needs, cavitation occurs. Hydraulic oil contains approximately nine percent dissolved air. When the pump does not receive adequate oil volume at its suction port, high vacuum pressure occurs.

This dissolved air is pulled out of the oil on the suction side and then collapses or implodes on the pressure side. The implosions produce a very steady, high-pitched sound. As the air bubbles collapse, the inside of the pump is damaged.

While cavitation is a devastating development, with proper preventative maintenance practices and a quality monitoring system, early detection and deterrence remain attainable goals. UE System’s UltraTrak 850S CD pump cavitation sensor is a Smart Analog Sensor designed and optimized to detect cavitation on pumps earlier by measuring the ultrasound produced as cavitation starts to develop early-onset bubbles in the pump. By continuously monitoring the impact caused by cavitation, the system provides a simple, single value to trend and alert when cavitation is occurring.

The oil viscosity is too high. Low oil temperature increases the oil viscosity, making it harder for the oil to reach the pump. Most hydraulic systems should not be started with the oil any colder than 40°F and should not be put under load until the oil is at least 70°F.

Many reservoirs do not have heaters, particularly in the South. Even when heaters are available, they are often disconnected. While the damage may not be immediate, if a pump is continually started up when the oil is too cold, the pump will fail prematurely.

The suction filter or strainer is contaminated. A strainer is typically 74 or 149 microns in size and is used to keep “large” particles out of the pump. The strainer may be located inside or outside the reservoir. Strainers located inside the reservoir are out of sight and out of mind. Many times, maintenance personnel are not even aware that there is a strainer in the reservoir.

The suction strainer should be removed from the line or reservoir and cleaned a minimum of once a year. Years ago, a plant sought out help to troubleshoot a system that had already had five pumps changed within a single week. Upon closer inspection, it was discovered that the breather cap was missing, allowing dirty air to flow directly into the reservoir.

A check of the hydraulic schematic showed a strainer in the suction line inside the tank. When the strainer was removed, a shop rag was found wrapped around the screen mesh. Apparently, someone had used the rag to plug the breather cap opening, and it had then fallen into the tank. Contamination can come from a variety of different sources, so it pays to be vigilant and responsible with our practices and reliability measures.

The electric motor is driving the hydraulic pump at a speed that is higher than the pump’s rating. All pumps have a recommended maximum drive speed. If the speed is too high, a higher volume of oil will be needed at the suction port.

Due to the size of the suction port, adequate oil cannot fill the suction cavity in the pump, resulting in cavitation. Although this rarely happens, some pumps are rated at a maximum drive speed of 1,200 revolutions per minute (RPM), while others have a maximum speed of 3,600 RPM. The drive speed should be checked any time a pump is replaced with a different brand or model.

Every one of these devastating causes of cavitation threatens to cause major, irreversible damage to your equipment. Therefore, it’s not only critical to have proper, proactive practices in place, but also a monitoring system that can continuously protect your valuable assets, such as UE System’s UltraTrak 850S CD pump cavitation senor. These sensors regularly monitor the health of your pumps and alert you immediately if cavitation symptoms are present, allowing you to take corrective action before it’s too late.

Aeration is sometimes known as pseudo cavitation because air is entering the pump suction cavity. However, the causes of aeration are entirely different than that of cavitation. While cavitation pulls air out of the oil, aeration is the result of outside air entering the pump’s suction line.

Several factors can cause aeration, including an air leak in the suction line. This could be in the form of a loose connection, a cracked line, or an improper fitting seal. One method of finding the leak is to squirt oil around the suction line fittings. The fluid will be momentarily drawn into the suction line, and the knocking sound inside the pump will stop for a short period of time once the airflow path is found.

A bad shaft seal can also cause aeration if the system is supplied by one or more fixed displacement pumps. Oil that bypasses inside a fixed displacement pump is ported back to the suction port. If the shaft seal is worn or damaged, air can flow through the seal and into the pump’s suction cavity.

As mentioned previously, if the oil level is too low, oil can enter the suction line and flow into the pump. Therefore, always check the oil level with all cylinders in the retracted position.

If a new pump is installed and pressure will not build, the shaft may be rotating in the wrong direction. Some gear pumps can be rotated in either direction, but most have an arrow on the housing indicating the direction of rotation, as depicted in Figure 2.

Pump rotation should always be viewed from the shaft end. If the pump is rotated in the wrong direction, adequate fluid will not fill the suction port due to the pump’s internal design.

A fixed displacement pump delivers a constant volume of oil for a given shaft speed. A relief valve must be included downstream of the pump to limit the maximum pressure in the system.

After the visual and sound checks are made, the next step is to determine whether you have a volume or pressure problem. If the pressure will not build to the desired level, isolate the pump and relief valve from the system. This can be done by closing a valve, plugging the line downstream, or blocking the relief valve. If the pressure builds when this is done, there is a component downstream of the isolation point that is bypassing. If the pressure does not build up, the pump or relief valve is bad.

If the system is operating at a slower speed, a volume problem exists. Pumps wear over time, which results in less oil being delivered. While a flow meter can be installed in the pump’s outlet line, this is not always practical, as the proper fittings and adapters may not be available. To determine if the pump is badly worn and bypassing, first check the current to the electric motor. If possible, this test should be made when the pump is new to establish a reference. Electric motor horsepower is relative to the hydraulic horsepower required by the system.

For example, if a 50-GPM pump is used and the maximum pressure is 1,500 psi, a 50-hp motor will be required. If the pump is delivering less oil than when it was new, the current to drive the pump will drop. A 230-volt, 50-hp motor has an average full load rating of 130 amps. If the amperage is considerably lower, the pump is most likely bypassing and should be changed.

Figure 4.To isolate a fixed displacement pump and relief valve from the system, close a valve or plug the line downstream (left). If pressure builds, a component downstream of the isolation point is bypassing (right).

The most common type of variable displacement pump is the pressure-compensating design. The compensator setting limits the maximum pressure at the pump’s outlet port. The pump should be isolated as described for the fixed displacement pump.

If pressure does not build up, the relief valve or pump compensator may be bad. Prior to checking either component, perform the necessary lockout procedures and verify that the pressure at the outlet port is zero psi. The relief valve and compensator can then be taken apart and checked for contamination, wear, and broken springs.

Install a flow meter in the case drain line and check the flow rate. Most variable displacement pumps bypass one to three percent of the maximum pump volume through the case drain line. If the flow rate reaches 10 percent, the pump should be changed. Permanently installing a flow meter in the case drain line is an excellent reliability and troubleshooting tool.

Ensure the compensator is 200 psi above the maximum load pressure. If set too low, the compensator spool will shift and start reducing the pump volume when the system is calling for maximum volume.

Performing these recommended tests should help you make good decisions about the condition of your pumps or the cause of pump failures. If you change a pump, have a reason for changing it. Don’t just do it because you have a spare one in stock.

Conduct a reliability assessment on each of your hydraulic systems so when an issue occurs, you will have current pressure and temperature readings to consult.

Al Smiley is the president of GPM Hydraulic Consulting Inc., located in Monroe, Georgia. Since 1994, GPM has provided hydraulic training, consulting and reliability assessments to companies in t...

In any hydraulic system, the hydraulic pump is usually the most expensive component and if it fails the whole system can be rendered inactive. Hydraulic pumps are extremely sensitive to contaminants and have the highest reliability risk. When a hydraulic pump starts to fail, it can force contaminants and debris further down the system and if this is not intercepted by an effective filter, the debris can then cause damage to other components. With this in mind, it is worth knowing the warning signs of common hydraulic problems and the precautions or actions that should be taken to prevent the lost work time and expense resulting from pump failure. As experts in hydraulic pump repairs, we at CJ Plant reveal the common causes of hydraulic pump failure.

In any mechanical system, components will be subject to wear and tear throughout their working life and will eventually wear out. Poor quality components will obviously have a shorter lifespan and should, therefore, be avoided, but there are a number of system failures common to all models of hydraulic pump that can easily be prevented if users are vigilant and pay attention to the operation of the system they are using. There are three common hydraulic pump failure symptoms that operators should be aware of that can be an indication of impending hydraulic pump failure:

If the hydraulic pump is making a whining noise or producing banging or knocking sounds, it can be assign of aeration or cavitation inside the pump. As the piston operates, pressure inside the pump drops and the resulting higher atmospheric pressure in the reservoir pushes hydraulic fluid along the inlet line into the pump. Anything that reduces this inlet flow can cause dissolved air in the oil to be drawn out forming air bubbles. When these reach an area of high pressure, the bubbles will implode under pressure and the resulting shockwaves will produce a high pitched whining sound. This can be assign of a damaged or blocked suction strainer or a plugged breather cap. High temperature in the fluid can also cause air to be released or low temperature can increase viscosity and slow fluid entering the pump so fluid temperature should be monitored closely. While not a common problem in the UK, systems operating high above sea level can also suffer from insufficient fluid entering the inlet due to atmospheric pressure being too low to push it through. Air from outside entering the system will result in aeration and will result in a knocking or rattling sound in the pump. As the pressure inside the system is lower than outside, any leaks in the suction line or the cylinder seal will cause air to enter the system. Poorly tightened connections on the suction line can also result in this problem. If this is suspected apply a layer of oil over any suspected location for a leak. If a hole appears in the oil as air is drawn in, the leak has been located. The noise will subside momentarily as this happens if aeration is the cause of the sound. If a leak is not located, check the reservoir. If the fluid level is too low, air can also been drawn in here or if the fluid entering the reservoir is dropping from a height it can cause bubbles to form as the fluid splashes which again can then enter the system. Any foaming of the fluid in the reservoir is another sign of aeration as the air exiting the system will cause foam to form.

Hydraulic fluid in a working system should never be above a temperature of eighty two degrees Celsius. A temperature exceeding this can be an indication of a malfunctioning heat exchanger or an overheating final drive motor. Cooler fins and the cooling fan should be cleaned and inspected for any damage, along with the fan belt, Any change in the pressure in the system from the manufactures settings will lead to an increase in temperature, along with other problems. Pressure levels should be checked in case deliberate or accidental adjustment of pressure has been carried out and relief valves checked in case they are damaged or incorrectly adjusted, as this can also lead to a change in system pressure and subsequent overheating. A lowered level of hydraulic fluid in the reservoir can also lead to overheating. if this is the case, the level of fluid should be topped up and the reservoir checked for any leaks that could be leading to this. All filters should checked for build up of debris or blockage as this can also affect pressure in the case of internal filters or cause insufficient flow of air in cooling systems. It is also worth considering the use of an offline filter

If your hydraulic system is running slower than usual, or showing increased cycle times, this is an indication of a drop in pressure within the system which can then lead to a subsequent overheating. This can be an indication of a leak in the system. If it is an external leak, it will usually be easy to locate and repair. However, if no external leak is visible it could be a sign of an internal leak in the gear pump or actuators and a hydraulic flow tester should be employed to test for this and locate the leak for repair.

While using good quality hydraulic fluid and implementing good contamination control systems can avoid many problems, sometimes the worst can still happen. If any of the above indicators are observed, they should not be ignored and the source of the problem located and repaired before they cause further damage. The implosion of air bubbles during cavitation can cause internal wear on the pump and dislodge debris or metallic fragments that can travel through the system, causing wear and erosion to components. These can then lead to further system failure. Aeration can lead to lowered lubrication inside the pump, leading to friction between metal components and the pump seizing up. This can not only damage the pump but also alter the pressure in the system, causing overheating and damage to other components.  Overheating can lower the viscosity of hydraulic fluid, lowering its ability to lubricate and degrading it and shortening its lifespan and causing heat damage to seals, leading to leaks.

Any one of these issues can lead to a cascade effect, causing damage to multiple parts of the overall system and resulting in lost work hours and revenue and expensive repairs. If your equipment is displaying any of these symptoms, call CJ Plant maintenance today. We understand that when your equipment is malfunctioning or damaged you need fast and efficient diagnosis and thorough professional repairs as soon as possible. We carry out hydraulic pump repair and plant maintenance to customers throughout the UK and offer free collection, wherever you are located if we cannot perform repairs on site. We will thoroughly inspect your faulty equipment and offer a full evaluation and no obligation quote for repair. After repair we will return your equipment fully restored to OEM standards with a written twelve month warranty. For further information on the services we provide, please contact us, we will be happy to help.

The industrial world is continuing to evolve. This means adding more sophisticated ways of reducing unscheduled downtime. However, even with all the automated processes, you still need discipline to ensure the fundamentals of troubleshooting and failure analysis/analytics aren’t lost. Adding devices to monitor operating conditions does little if you can’t put that feedback into context.

Properly analyzing the mode of failure can provide valuable information about what caused that failure, and thus can be used in an effort to resolve underlying issues. Resolving these underlying issues is the true key to avoiding future unscheduled downtime.

There are several common modes of failure for variable displacement piston pumps. Understanding these modes of failure, the causes, warning signs, and the prophylactic means of monitoring will help you to reduce unscheduled downtime.

These four modes account for the vast majority of all failures seen in the thousands of units inspected and repaired each year by the service technicians.

The fatigue that results from transient pressure spikes will present in the form of broken pistons (at the neck), shafts (where the cylinder barrel rides or at the tail), sheered control pins, damaged yokes, or the appearance of cracks between the kidneys of the cylinder barrel. Of the four common modes of failure, this is by far the most difficult problem to identify