what causes a hydraulic pump to get hot price

Hydraulic pumps generate heat while they run. However, hydraulic fluid temperature should never exceed180 degreesF (82 degrees C) under normal working conditions. If your hydraulic pump temperature rises above this, then that is a sign that your pump is likely overheating. One of the most common causes of hydraulic system failure is a hydraulic pump that runs too hot or overheats.

When a hydraulic pump runs at a too-high temperature for too long, it can ultimately lead to pump failure. Once a hydraulic pump begins to fail, it can potentially damage the entire hydraulic system by sending contaminants and debris into the system that can damage its other components.

In addition, when some hydraulic fluids are subject to high temperatures, they can thin and lose their viscosity. When hydraulic fluid is too thin, it is much more likely to leak, and fluid that has lost its viscosity cannot lubricate your pump properly. Extremely hot fluid can also damage pump seals, further increasing the chance of a pump leak.

Some hydraulic fluids thicken and oxidize when exposed to high heat instead of thinning. When hydraulic fluids are too thick, they can restrict flow throughout the entire hydraulic system, which leads to your system heating up even further.

The sooner you determine why your hydraulic pump is running hot and repair the cause of the problem, the less likely your hydraulic system will develop irreversible damage or fail completely.

Hydraulic pumps overheat for many reasons. Just a few of the most common causes of hydraulic pump overheating include: Contaminated hydraulic fluid. When fluid has debris and dirt, contaminant particles can quickly build up on hydraulic system filters, leading to filter clogs. Your pump has to work harder to pump fluid through clogged filters, which leads to overheating.

Aeration. Air leaks at seals and fittings on your hydraulic system components can lead to air entering your system and forming bubbles in your fluid. Air bubbles generate heat when your system compresses them and then pass this heat into the surrounding fluid, overheating it.

Low reservoir fluid. Since your hydraulic system releases some of the heat it creates into reservoir fluid, a low reservoir fluid level can contribute to overheating.

Blocked or damaged heat exchanger. This component is also an important part of your hydraulic pump"s cooling system. If it is blocked or damaged, then it cannot help remove heat from your pump properly.

Once your hydraulic pump beings overheating, you need to find the cause of the problem and repair it. That way, your pump can begin operating within its ideal temperature range again.

If your pump overheats due to fluid contamination, then either remove all contaminants from existing fluid or remove the current contaminated fluid from the system and add fresh fluid. Be sure to filter all fresh hydraulic fluid before you add it to your system because even this fresh fluid can contain contaminants. Also, replace your fluid filters on a regular basis to prevent the overheating that can occur when these filters become blocked with debris.

If air has entered your system through leaky seals and fittings, then have a hydraulic system repair expert inspect and replace or tighten these fittings. Have a hydraulic system repair expert also look at heat exchanger damage to determine if the exchanger needs repairing or replacing.

Finally, be sure to check your system"s reservoir fluid level on a regular basis. Add new fluid when necessary to help this reservoir perform its important task of helping to keep your pump cool.

Your hydraulic pump should always operate within its ideal temperature range. If your pump is running hot, then contact the hydraulic pump experts at Quad Fluid Dynamics, Inc., forhydraulic pump diagnosis and repairtoday.

Is your hydraulic pump getting excessively hot during normal operation? Pumps do generate heat when running, however they are designed with specific heat parameters in mind. Overheating is an abnormal condition that leads to destructive issues such as thinning of hydraulic fluid, which leads to reduced lubrication, metal-on-metal contact of moving parts. And accelerated pump wear and failure.

Therefore it is never a good idea to ignore a pump that is exceeding its heat parameters under normal load. There are a number of factors that contribute to an excess buildup of heat and in this article, we’ll explain some of these issues.

Hydraulic fluid viscosity refers to the thickness or “resistance to pouring” of your hydraulic fluid. This is very important to the correct operation of your pump. The fluid not only transmits the power that moves your drives and actuators. It also lubricates internal components and removes heat from the system. Hydraulic fluid is designed to operate at a specific temperature range. As it heats, it becomes thinner and eventually it will lose the ability to lubricate moving parts. The increased friction may cause the pump to heat up, and naturally increased wear will be taking place when this is happening. On the other hand, hydraulic fluid that is too thick flows less efficiently within the system, which also results in heat buildup.

Fluid that is contaminated with dirt, debris, water and other impurities may cause heat build up in a few ways. Blocked fluid filters, pipes and strainers place undue load on the pump or even lead to pressure drops on the back side of filters that cause cavitation.

Low fluid levels can result in a condition in which not enough flow is reaching the critical hydraulic components and moving parts. This is known as oil starvation and just like running your car without oil, it will increase metal-on-metal friction and lead to increased heat and wear. Oil starvation can also be caused by clogged hydraulic filters, incorrect fluid reservoir design.

Cavitation is the rapid formation and implosion of air cavities in the hydraulic fluid. When these air cavities collapse under pressure, they generate a lot of heat. In fact, temperatures can reach up to 2700 degrees C at the point of implosion! Not only does cavitation compromise the lubrication properties of the oil, the excessive heat that is generated is extremely damaging to the hydraulic pump and the system as a whole. Attacking hoses and seals and causing metal components to expand and wear.

This happens when air makes its way into the system via air leaks at points like pump seals, and pipe fittings. And what happens next in a hydraulic system? Compression! Air generates heat when compressed, which naturally leads to an increase in temperature if left untreated. In extreme circumstances it can also lead to ‘hydraulic dieseling’ whereby compressed air bubbles actually explode in the same process that powers diesel engines. This is not good and leads to degradation of the fluid and damage to system components through loss of lubrication and burning of seals.

As pumps wear, the internal leakage or “slippage” increases. Essentially, fluid is able to make its way past tight fitting components, which reduces the efficiency of the pump, but in addition, as this occurs, fluid moves from a high pressure to a low pressure without doing any mechanical work, since according to the laws of physics energy cannot be destroyed, it is instead converted into heat.

A build-up of excessive heat is a symptom of hydraulic pump problems, but it is far from the only signal that there may be something wrong. There are other important warning signs that you should pay attention to. These include unusual noises, pressure problems and flow problems. Each of these symptoms provide clues about any potential pump problems that need to be addressed - so it’s important to familiarise yourself with all of these issues. To help, we’ve created a downloadable troubleshooting guide containing more information about each of these issues. So that you can keep your system up and running and avoid unplanned downtime. Download ithere.

When hydraulic oil is getting overheated, there could be several common causes that also cause the system to overheat. First, it is crucial to understand the type of hydraulic system you are using to begin troubleshooting why the system is overheating.

The first cause of hydraulic oil overheating is when the hydraulic equipment system parts and components are nearing the end of their useful lifespans. As they degrade, due to increased internal leakage, they have to work harder to maintain the desired system pressure.

For example, your hydraulic pump is wearing out and needs to be replaced. Due to internal wear pressurised fluid escapes from the high pressure side to the low pressure side generating heat increasing the temperature of the hydraulic fluid and causing circuit overheating.

It is understood that you may want to make system upgrades or changes to customize the system to reflect your specific needs. However, when you do not consider the entire system, it can cause the system to work hard, give off more heat, and increase hydraulic oil temperatures, leading to circuit overheating.

For instance, you may want to increase the fluid flow rate through the system. However, you did not account for the size of hoses and tubing to accommodate the higher flow rates. As a result, the system has to work hard to force the increased flow rates through incompatible hoses and tubes, resulting in more heat generation and fluid overheating.

Tweaking your hydraulic system is perfectly acceptable to optimize its performance. However, where many people go wrong is they only adjust one part of the system and fail to think about how the adjustment will impact other parts of the system.

For example, suppose you make an adjustment to the pump compensator and increase the pressure yet fail to also make a similar adjustment to the relief valve. In this instance the relief valve will blow off more frequently generating more heat and therefore increasing the circuit fluid temperature.

Every component in a hydraulic system imposes a load on the pump, this is referred to as the pressure drop across the particular component. The figure will vary depending upon the flow rate and the energy lost from the fluid due to the pressure drop is converted into heat. If the overall pressure drop across all the components in the circuit unexpectedly increases so the heat generated across the circuit will also increase.

If the fluid is not cooled to compensate for this the fluid temperature continues to increase as the other parts and components generate excessive heat.

If there is dirt, sludge, debris, or water in the hydraulic fluid, the system will generate more heat as it attempts to compensate for the contaminants and push the fluid through the system. Therefore, it is always vital to check your fluid for contamination and change it and or improve fluid filtration when required.

After troubleshooting overheating problems, if you have determined it is not due to the four common causes mentioned above, then there are two general ways you can resolve fluid overheating problems. You can either increase the reservoir capacity to dissipate heat or decrease the amount of heat being generated by the system.

Another way to increase the heat dissipation is to inspect the current heat exchangers, if they are being used, and make the appropriate adjustments. In some cases, you may want to install additional heat exchangers to help reduce the fluid temperature.

In addition, check the airflow around the reservoir as the higher the airflow the more efficiently the reservoir radiates the heat from the fluid held inside it.

To find hydraulic parts, components, and accessories to help you resolve hydraulic oil overheating problems, or if you require assistance in troubleshooting system overheating, please feel free to contact White House Products, Ltd. at +44 (0) 1475 742500 today!

Remember that hydraulic system running at 145 F last fall? The one you didn’t worry about with cooler weather on the way? In the middle of summer, it could be operating even hotter—if it hasn’t already shut down. That’s because any industrial hydraulic system that runs higher than 140 F is too hot. The resulting problems are costly:

Fluid power specialist Al Smiley of GPM Hydraulic Consulting, Monroe, GA, has dealt with countless hydraulic systems in industrial operations throughout the past 20 years. We asked him for ways to troubleshoot hot-running systems.

“First things first,” said Smiley, “it’s important to keep in mind that all hydraulic systems generate a certain amount of heat.” Approximately 25% of the input electrical horsepower will be used to overcome heat losses in a system. Whenever oil is ported back to the reservoir, and no useful work is done, heat will be generated.

The tolerances inside pumps and valves normally permit a small amount of oil to continuously bypass a system’s internal components, causing the fluid temperature to rise. When oil flows through the lines, several resistance points are encountered. For example, flow-control, proportional, and servo valves control the flow by restricting it. When oil flows through those valves, a pressure drop occurs. This means a higher pressure will exist at the inlet port than at the outlet port. Any time oil flows from a higher to a lower pressure, heat is generated and absorbed in the oil.

When a hydraulic system is designed, the reservoir and heat exchangers are sized to remove that heat—some of which is allowed to dissipate through the reservoir walls to the atmosphere. “Heat exchangers, if properly sized,” Smiley noted, “should remove the balance of the heat and allow the system to operate at approximately 120 F.”

Fig. 1. Pressure-compensating piston pumps are the most common type used in industrial hydraulic systems. The tolerances between the pistons and barrel are approximately 0.0004 in.

The pressure-compensating piston pump (Fig. 1) is the most commonly used type in industrial hydraulic systems. Tolerances between the pistons and barrel are approximately 0.0004 in. A small amount of oil at the pump outlet port will bypass through these tolerances, flow into the pump case, and then be ported back to the reservoir through the case-drain line. “This case-drain flow,” noted Smiley, “does no useful work and is, therefore, converted into heat.”

According to Smiley, the normal flow rate out of the case-drain line is 1% to 3% of the maximum pump volume. For example, a 30-gpm pump should have approximately 0.3 to 0.9 gpm of oil returning to the tank through the case drain. “A severe increase in this flow rate,” he explained, “will cause the oil temperature to rise considerably.”

To check the flow rate, the line can be ported into a container of known size and the flow timed “unless personnel have verified that the pressure in the hose is near zero psi,” Smiley warned, “they should not hold the line during this test.” The line should, instead, be secured to the container, he advised.

A flow meter can also be permanently installed in the case-drain line to monitor flow rates. Check it regularly to determine the amount of bypassing. The pump should be changed when the oil flow reaches 10% of the pump volume.

Fig. 2 (top). During normal operation of this typical variable-displacement, pressure-compensating pump, when system pressure is below the compensator setting (1,200 psi), the internal swash plate is held at maximum angle by the spring. This arrangement allows the pistons to fully stroke in and out, permitting the pump to deliver maximum volume. Flow from the outlet port of the pump is blocked through the compensator spool.

Fig. 3 (bottom). Once the pressure builds to 1,200 psi, the compensator spool shifts, directing oil to the internal cylinder. As the cylinder extends the angle of the swash plate, it moves to a near-vertical position. At this point, the pump will only deliver enough oil to maintain the 1,200-psi spring setting. The only heat generated by the pump at this time is from the oil flowing past the pistons and through the case-drain line.

Figure 2 is a diagram of a typical variable-displacement pressure-compensating pump. During normal operation, when the system pressure is below the compensator setting (1,200 psi), the internal swash plate is held at maximum angle by the spring. This allows the pistons to fully stroke in and out and let the pump deliver maximum volume. Flow from the pump’s outlet port is blocked through the compensator spool.

Figure 3 shows the condition of the same pump when pressure reaches 1,200 psi, and the compensator spool shifts, directing oil to the internal cylinder. As the cylinder extends the angle of the swash plate, it moves to a near-vertical position. At that point, the pump will only deliver enough oil to maintain the 1,200-psi spring setting. “The only heat generated by the pump at this time,” Smiley noted, “is from the oil flowing past the pistons and through the case-drain line.”

“As long as the system cooler and reservoir can remove at least 0.6296 horsepower of heat,” Smiley stated, “the oil temperature should not increase.” If the bypassing increases to 5 gpm (as shown below), the heat load increases to 3.5 horsepower. If the cooler and reservoir aren’t capable of removing at least 3.5 horsepower, he said, the oil temperature will increase.

Fig. 4. Many pressure-compensating pumps incorporate a relief valve as a safety backup in case the compensator spool sticks in the closed position. The relief valve should be set 250 psi above the pressure-compensator setting. Since the relief-valve setting is above that of the compensator, no oil should flow through the relief-valve spool. Therefore, the valve tank line should be at ambient temperature.

Many pressure-compensating pumps incorporate a relief valve as a safety backup in case the compensator spool sticks in the closed position (Fig. 4). According to Smiley, the relief valve should be set 250 psi above the pressure-compensator setting. If the relief valve setting is above that of the compensator, no oil should flow through the relief-valve spool. Therefore, the tank lines of these valves should be at ambient temperature.

If, however, the compensator were to stick in the position shown in Fig. 2, the pump will deliver maximum volume at all times and oil not used by the system will return to the tank through the relief valve. “If this occurs, Smiley said, “significant heat will be generated.”

Smiley lamented that plant personnel often randomly adjust the pressures in these systems in an attempt to make the equipment run better. “If the local knob turner turns the compensator pressure above the setting of the relief valve,” he explained, “the excess oil will return to the tank through the relief valve, causing the oil temperature to rise 30 or 40 degrees. If the compensator fails to shift or is set above the relief-valve setting, a tremendous amount [of heat] will be generated.”

Assuming the maximum pump volume is 30 gpm and the relief valve is set to 1,450 psi, the amount of heat generation can be determined using the following formula.

If a 30-hp electric motor is used to drive this system, 25 hp will be converted to heat when in the idle mode. Since 746 W = 1 hp, then 18,650 W (746 x 25) or 18.65 kW of electrical energy will be wasted.

Smiley cited several other heat-generators in hydraulic systems and the importance of maintaining these components. These include accumulator dump valves and air-bleed valves that fail to open, thus allowing oil to bypass to the reservoir at high pressure. He also pointed to heat generated by oil bypassing cylinder piston seals.

If an air-type heat exchanger is used, clean the cooler fins—using a degreaser, if necessary—on a regularly scheduled basis. The temperature switch that controls the cooler fan should be set at 115 F.

If a water-cooled system is used, a modulating valve should be installed in the water line to regulate the flow through the cooler tubes to 25% of the oil flow.

Smiley noted that reservoirs should be cleaned at least annually, lest sludge and other contaminants coat their bottoms and sides. This would allow the reservoir to act as an incubator instead of dissipating heat to the atmosphere.

Smiley offered a final helpful hint for hot-hydraulics troubleshooters: “The next time a heat issue surfaces in one of your hydraulic systems, look for oil flowing from a higher to a lower pressure in the system. That is where you’ll find your problem.” MT

Is it really possible to design reliability into a hydraulic system? Let’s consider one of oldest problems that plague many hydraulic system designers, reliability engineers and maintenance technicians. They ask, "My hydraulic system is running hot—what’s causing that?"

First, we must understand that hydraulic horsepower either goes to work as energy or is wasted energy in the form of heat. If a hydraulic system is designed to be efficient and is operated and maintained properly, it won’t get hot.

There must be a pressure drop for oil to flow in a hydraulic system. However, there are certain pressure drops that are unnecessary and create a given amount of heat. If you look at the pressure drop for a half-inch standard 90-degree fitting with a 22.10-psi drop per fitting and then compare that to the pressure drop of a long-radius 90-degree fitting, it is significantly less at 2.98 psi drop per fitting.

With a 22.10-psi drop multiplied by 25 gallons/minute (gpm), divided by a 1,714-psi constant, you get 0.322 wasted horsepower. Multiply that by 2,545 Btus/hour per 1 hp, or by 819.5 Btus per hour of heat that will be generated as a result of using this type of fitting.

If you think that is insignificant, go out and count the 90-degree fittings in one of your circuits. I think you will be surprised at the amount of heat being generated for no apparent reason. If your circuit had 20 of the 90-degree fittings, that would generate 16,390 Btus of heat that your system was not designed to eliminate.

At this point, many clients ask for a heat exchanger to "mask" the real problem of a system that wasn’t designed properly. If you really think about it, you are paying extra money to produce this additional heat, and then paying more money to eliminate it with a cooling device. What you are paying for is the expenses of extra horsepower for an air-type cooler, the cost of treating the water with a water-type cooler, plus installation and maintenance.

With a 2.98-psi drop multiplied by 25 gpm divided by the 1,714-psi constant, you get 0.043 wasted horsepower. Multiply that by 2,545 Btus/hour per 1 hp, and you get 109.4 Btus per hour of heat generated as a result of using the long-radius fitting.

How much is that costing you per year in dollars? As a general rule, at 440 V, a three-phase motor draws 1.25 amp per horsepower. For this example, let’s assume our power factor (pf) is 1.0 and our plant is in Florida, where the average commercial electricity rate is $9.66/kWh.

With the standard 90-degree fitting, you’re wasting 6.4 hp multiplied by 1.25 amps per horsepower for a 440 V electric motor, or 8 amps. At more than 8,760 hours of operation per year, you’d wind up with 53,345 kWh per year. And at $0.0966/kWh, that comes to $5,153.11/year per fitting.

With the long-radius 90-degree fitting, you’re wasting 1.07 amps. Over the same 8,760 hours of operation, that’s 7095.95 kWh/year, or just $685.43/year per fitting.

Paul Craven, CFPHS, manages one of Motion Industries’ repair shops. He is a fluid power specialist and is certified by the International Fluid Power Society as a fluid power hydraulic specialist. For more information, go to www.motionindustries.com.

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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!

Hyundai hydraulic pumps are integral parts of excavators. The company is the third largest manufacturer in the world. As one of the leading brands, Hyundai has been popularized after producing high quality and durable products over time.

An excavator Hyundai hydraulic pump can overheat for a variety of reasons. The most common cause is actually running the pump at too low of an RPM. When the pump is not turning fast enough, it can’t move the oil through the system quickly enough and it starts to overheat. Another common cause is a blockage in the system somewhere. This could be a blockage in the suction line, return line, or even in the pump itself. If there is a blockage, the oil can’t flow properly and it will start to overheat.

If your excavator Hyundai hydraulic pump is overheating, there are a few things you can do to try and fix the problem. First, check the RPM of the pump. If it is running too low, increase it until it is running at the proper speed. Next, check for any blockages in the system. If you find one, clean it out and see if that fixes the problem. Finally, if neither of those two things works, you may need to replace the pump itself.

There are many potential causes of an excavator Hyundai hydraulic pump overheating. The most common cause is a loss of hydraulic fluid due to a leak in the system. Other causes can include a build-up of dirt and debris in the system, or a problem with the pump itself.

If you suspect that your excavator’s hydraulic pump is overheating, the first step is to check for leaks. If you find a leak, make sure to repair it as soon as possible. If there is no leak, then you will need to clean out the system to remove any dirt or debris that may be causing the problem.

If you are still having problems with your excavator’s hydraulic pump overheating, it may be necessary to replace the pump itself. This is a more complex repair, so it is best to consult with a qualified mechanic or dealer before proceeding.

There are several potential causes of an excavator Hyundai hydraulic pump overheating, but the most common cause is simply because the pump isn’t getting enough oil. This can happen for a variety of reasons, such as a leaking oil line or an incorrect amount of oil being used. Another potential cause is that the pump isn’t getting enough cooling water, which can be caused by a clogged water filter or an insufficient water supply. Whatever the cause, it’s important to get the problem fixed as soon as possible to avoid damage to the pump.

The Hyundai hydraulic pump is located in the engine bay of the excavator. It is responsible for providing hydraulic pressure to the excavator’s hydraulic system. If the pump overheats, it can cause damage to the hydraulic system and potentially lead to a loss of excavator performance. There are a few things that you can do to prevent the pump from overheating:

– Inspect the pump regularly for any potential leaks. Leaks can cause the fluid level to drop and also allow air to enter the system, which can cause problems.

If you’re noticing that the Hyundai hydraulic pump on your excavator is overheating, there are a few things you can do to prevent it. First, make sure that the pump is getting enough oil. If the pump isn’t properly lubricated, it will overheat. You should also check the cooling system to make sure it’s working properly. If the pump is still overheating, you may need to replace the seals or bearings.

If you have an excavator Hyundai, you may have experienced your hydraulic pump overheating. This can be a major problem, as it can lead to damaged equipment and even injuries. However, there are a few things you can do to help prevent this from happening. make sure that your excavator is properly ventilated. Second, check the fluid levels in your hydraulic system regularly. Third, use aHydraulic Pump Overheating Prevention Kit. By following these simple tips, you can help ensure that your hydraulic pump doesn’t overheat and cause damage to your equipment or yourself.

You can use multiple different upgrades and tuning methods on hydraulic systems. Many users will invest in upgrades that promise more flow and speed. The issue with these upgrades is that they"re not always fit for the hydraulic systems they"re applied to.

Since everything needs to stay in balance, you must make sure your upgrades match the entirety of your hydraulic system. For example, a higher flow pump can help give increased capabilities to a hydraulic system, but did you also check to see if the system"s hoses and piping can handle that increase in flow?

The increased flow can hit your smaller hoses hard and require more pressure just to get through them. This goes for any part of the hydraulic system that isn"t readily capable of handling more flow.

If a component becomes a flow throttle, the increase in pressure at the site can cause an overall pressure drop in the system. Also, the energy required to force flow will directly translate to an increase in heat, which lowers the systems efficiency and effectiveness.

When you make upgrades, also ascertain if you need to change other components. In the example of the higher flow pump, you can simply increase your hose size, and that makes all the difference.

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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.

A simple and well-practiced maintenance plan can help prevent issues from developing and even discover issues early, leading to shorter and less costly downtimes.

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

The operator’s guide of your machine will indicate the correct oil to use in your machine, but operators should also be aware of the conditions they are working under and be mindful if oil should be updated to match those conditions.

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.

This article is part of the H&R Construction Equipment Parts How To series, designed to give readers and viewers a brief glimpse of the work of our Recon and Rebuild team or to provide basic maintenance and help tips. Whether you’re rolling up your sleeves and about to get your hands greasy or you’re just looking for a better understanding of a part, please practice proper safety protocols and understand this is only a basic guide. Consult a trained professional before performing any unfamiliar tasks.

?I get e-mails like this all the time. I never find time to read them. I decided to read Issue #30 and I couldn"t put it down. I"ll make time from now on.?

?I just love this newsletter. As a Hydraulics Instructor for Eaton, I make copies and distribute them to my students as I address various topics. Please keep "em coming.?

Overheating isa frequent problemwithin hydraulic systems that may be determined by specific components. Thisinternal problem lies within the pump and causes a hydraulic system to overheat in the following ways:

Contaminated hydraulic fluid is a common cause for a Hydraulic system to overheat. This can occur when the container is not sealed properly which causes dust, dirt,debris,or moisture to contaminate the fluid.With hydraulic systems running at higher pressures and more efficiently than ever before, it is important tomonitorthe cleanliness of one’s hydraulic fluid. Reducing contamination can decrease damage andwillallowoneto get the most out oftheirequipment.

Wrong valve calibration could resultin pressure difficulties which can cause a hydraulic system to overheat. The main cause of this is when a facility’s plant design changes and maintenance recalibrate the pressure relief valves for the updated operating pressure. If maintenance adjusts the pressure,and it stilldoes notsolve the problem, the pressure relief valve may have to be replaced entirely. Erosion to a valve is a common occurrence as dirt and debris settle and collectthroughout time. Maintaining the correct pressure will help your system keep up with production and not slow down.

Aeration in a hydraulic system can bea common issueand is caused by an outside air leak in the suction line.The pressure used in the suction line of hydraulic systems is below atmospheric pressure, so oilcannotleak out, but air can leak in.This will occur when there are loose, leaky seals and fittings which will allowtheair to seep in.Aeration can have severalnegative effectson top of overheatingsuch as increasedpump cavitation, excessive noise, and loss of horsepower.Some symptoms of Aeration may include foaming of the fluid, irregular movements, and banging and or loud clicking noises as the hydraulic system compresses and decompresses.

A blocked heat exchanger is significant toheating one’s hydraulic system, while cooling it down is just as important.Aninfrared thermometer isan effective wayto checkthe temperatureof a heat exchanger. Theadjustments can be made according tothedesign of theflow rateof oil.Make sure to replace the fluid fitterslocatedin the pumpon a regular basis to ensure theywill not get blocked andoverheat.

Oil Type plays a critical role inany hydraulic system. The wrong oil will not only affect the performance of the system but also cut down the lifespan of the machine. Theoil Viscositydeterminesthe maximum and minimum temperatures in which a hydraulic system can safelyoperate.Thin oils have a lowviscosity andflow more easily at low temperaturesthanthicker oils that have a higherviscosity.If the oil is too thin it can cause internal friction whichcreates heat and cancausethe system to overheat.

Low reservoir fluid is a common cause ofoverheating in hydraulic systems as itreleasesbuilt-upheatfrom the machineintothe fluid. Not having enough reservoir fluid cancontribute tocavitation andultimate damage to the pump.

Hydraulic pump failure candamage the entire hydraulic system.When a pump fails,debris, dirt, and grime kick out downstreamand can affect theoil,filter,valves, fluid, and actuator.Contactour KICK@$$ hydraulic system repair professionalsat Allied Hydraulic to avoid these problems.

Everyone knows that contamination can be catastrophic to a hydraulic system. But heat can also be detrimental to hydraulic fluid and the components within that system.

Heat contamination reduces oil viscosity, which in turn reduces the fluid’s ability to lubricate components. This thinning of the oil causes surface-on-surface wear. Without proper viscosity levels, as components rub against each other — such as a wear plate and the slippers on a piston pump — they wear at accelerated rates.

This wearing also softens metals, which in turn increases the rate of wear. For example, anywhere there’s metal rubbing on and near to other pieces of metal (even if it’s two different materials such as bronze or stainless) as the metal heats up, it becomes softer and it wears away more quickly. This problem is exacerbated if other forms of contamination are present.

Additionally, heat can break down system seals. As they break down, flecks of rubber can enter the system, causing internal contamination. And, if a seal fails, external contamination will easily enter through cylinder rods.

Heat enters a hydraulic system in multiple ways. One culprit is ambient heat. For example, you may have a blast furnace dipping molten metal into a ladle. It is imperative that the hydraulic actuators and the oil used within them are designed for that type of environment.

Another thing to be aware of is internally generated heat; this often is generated from piston pumps, inefficient gear pumps or friction created by other internal components. For example, while useful in specific applications, low-speed, high-torque motors may only have a 60-70% efficiency rating. This means 30 to 40% of the system energy is wasted as pure heat. This internal heat reduces lubrication, increasing friction and reducing lubricity. This may eventually cause the motor to wear out.

So how to do you filter out or remove heat from a system? First, you should try to design a system that doesn’t create it in the first place. Second, in regular maintenance, always keep an eye on the reservoir levels. You should have three times the pump capacity available in the reservoir. Ensure also that the reservoir is clean and not near heat sources (such as direct sunlight or machines that generate heat).

Finally, if there is any device that could be considered a heat filter, it would be a cooler or heat exchanger, which uses water or air to bring hydraulic fluid temperature down. Several types exist.

The first is a shell and tube heat exchanger, in which coolant water flows through internal system ports and tubing while the warmer hydraulic fluid circulates through others. The heat is transferred from one fluid to the other, thus bringing the overall fluid temperature down.

Air coolers can also be used. While not as effective, they are sufficient and often easier to use. These use a fan and radiator-type cooler, and often can be driven by hydraulic motors, simply to force cold air over the hot fluid inside.

When a hydraulic system stops working as intended, whether it is due to a major leak or a failing pump, it can bring productivity to a grinding halt (both literally and figuratively). The process of tracking down the source of the problem involves troubleshooting, which takes considerable skill, experience, and common sense. However, there are some valid guidelines and good hints to help with the process.

The first step in effective troubleshooting is making sure you understand what the problem is — and this can involve asking quite a few questions. If someone says, for example, “The pump is vibrating really bad” then you need to delve a bit deeper with questions, such as:

There are certain problems commonly prevent hydraulic systems from working properly, such as an inoperative system or overheating hydraulic fluid. What follows are some troubleshooting tips for typical issues that arise in hydraulic systems.

If the hydraulic system is inoperative, there are several things that can be checked. Verify the hydraulic fluid levels and keep in mind that leaks can lead to significant loss of hydraulic fluid. Take a look at the hydraulic filters, because if they are dirty or clogged badly enough, it can seriously impact performance. Check for restrictions in the hydraulic lines; restrictions often take the form of a collapsed or clogged line.

Make sure there are no air leaks in the pump suction line. Also inspect the pump itself; if it is worn, dirty, or out of alignment, it will affect system performance. The pump drive can be a source of issues if it the belts or couplings are slipping or broken. It may be time to replace some components; as they begin to wear, it can lead to internal leakage. It is also a good idea to make sure that the unit is operating within its maximum load limits.

When a hydraulic system begins working more slowly than normal, one of the causes can be hydraulic fluid that is too thick, which may be due to cold temperatures or the use of an

If the system is operating in an erratic, unpredictable manner, the most common causes are air trapped in the system, hydraulic fluid that is too cold (which means the equipment needs an opportunity to warm up before use), and damaged internal components such as bearings and gears.

Another common issue with hydraulic systems is excessive/abnormal noise or vibration. If it is the pump that is noisy, then check that the oil level is sufficient, the correct type of fluid is being used, and that the oil is not foamy. If the oil is foamy, that points to air in the fluid which can lead to cavitation and expensive damage. It is also wise to verify that the inlet screen and suction line are not plugged. For both pumps and hydraulic motors, there can also be internal issues, namely worn or misaligned bearings. And do not forget to make sure that the couplings are secure and tight. Keep in mind that pipes and pipe clamps can vibrate if they are not secured properly.

Excessive heat is never a good sign in a hydraulic system and often leads to a system working at sub-optimal levels. One of the purposes of hydraulic fluid is to dissipate generated heat, but the system should not be generating enough heat to cause the fluid to reach high temperatures.

There can be a host of causes behind hot hydraulic fluid, starting with contaminated hydraulic fluid or fluid levels that are too low. There may be oil passing through the relief valve for too long at a time; in this case, the control valve should be set to neutral when it is not in use. Worn out components within the system can also lead to excessive temperatures due to internal leakage.

If there are restrictions in the line or dirty filters, hot hydraulic fluid will result. If hydraulic fluid viscosity is too low, it can lead to overheating as well. Finally, there may be a need to make sure that the oil cooler is functioning correctly and that the key components are clean enough for heat to radiate away from them.

We have discussed low viscosity as a symptom, but it also qualifies as its own problem. When trying to determine why the fluid is not as viscous as it should be, the three things that need to be checked are damage to the oil (often from extreme temperatures or aging), use of the wrong type of hydraulic oil, or the presence of water in the hydraulic fluid. In all three cases, the system will need to be flushed and the oil replaced.

Having no flow within the hydraulic system is a serious issue that can have several different sources. The first step is to determine exactly where the fluid flow stops, such as failure of the pump to receive fluid at the inlet (usually the result of a clogged line or dirty strainers) or a failure for fluid to exit the outlet, which could be due to a pump motor that needs replacing, a sheared coupling between the pump and drive, or a pump/drive failure. It would also be a good idea to make sure the pump rotation is set correctly and the directional valves are in the correct position. The most expensive problem would be a damaged pump that needs to be replaced or repaired.

The first step in troubleshooting is to gather as much information about the problem as possible and then pull the hydraulic schematics for the system. From there, you basically follow a process of elimination until the root of the problem is uncovered. Something else to keep in mind with regard to troubleshooting, however, is that once you have tracked down the source of a problem, it may lead you to yet another problem that will need some troubleshooting. Getting your hydraulic system back in working order can be a time consuming process.

For example, you may uncover that the cause of overheating hydraulic fluid is low viscosity — but why is the fluid insufficiently viscous? The troubleshooting process is not over until that issue is uncovered. Take, as another example, the case of a pump whose internal components have worn out and affected overall system performance — why did the components prematurely wear? It may be a cause of misalignment, insufficient lubrication, or contaminated fluid. A good hydraulics technician will not just track down and address the problem, but will keep troubleshooting to make sure that the problem does not happen again.

At MAC Hydraulics, we understand the importance of having a functional, efficient hydraulic system. We know that any downtime costs money and time that your company simply does not have to spare. That is why we offer comprehensive hydraulic services that include 24-hour emergency on-site troubleshooting and repair services. Our team of experienced hydraulics experts can work on motors, pumps, valves, cylinders, and systems. We serve a wide range of industries, including everything from paper and pulp processing to aerospace to construction equipment. When complex repairs are called for, we have a full machining center and certified welders. We also offer customized maintenance plans tailored to your needs and your equipment.

The second leading cause of hydraulic pump failure, behind contamination, is cavitation. Cavitation is a condition that can also potentially damage or compromise your hydraulic system. For this reason, understanding cavitation, its symptoms, and methods of prevention are critical to the efficiency and overall health of not just your hydraulic pump, but your hydraulic system as a whole.

The product of excessive vacuum conditions created at the hydraulic pump’s inlet (supply side), cavitation is the formation, and collapse of vapors within a hydraulic pump. High vacuum creates vapor bubbles within the oil, which are carried to the discharge (pressure) side. These bubbles then collapse, thus cavitation.

This type of hydraulic pump failure is caused by poor plumbing, flow restrictions, or high oil viscosity; however, the leading cause of cavitation is poor plumbing. Poor plumbing is the result of incorrectly sized hose or fittings and or an indirect (not straight or vertical) path from the pump to the reservoir. Flow restrictions, for example, include buildup in the strainer or the use of an incorrect length of hose or a valve that is not fully open. Lastly, high oil viscosity—or oil that is too viscous—will not flow easily to the pump. Oil viscosity must be appropriate for the climate and application in which the hydraulic pump is being used.

The greatest damage caused by cavitation results from the excessive heat generated as the vapor bubbles collapse under the pressure at the pump outlet or discharge side. On the discharge side, these vapor bubbles collapse as the pressure causes the gases to return to a liquid state. The collapses of these bubbles result in violent implosions, drawing surrounding material, or debris, into the collapse. The temperature at the point of implosion can exceed 5,000° F. Keep in mind that in order for these implosions to happen, there must be high vacuum at the inlet and high pressure at the outlet.

Without a pressure condition at the outlet, or discharge side, these vapors merely form voids in the oil that reduce lubrication effectiveness. This results in friction and wear, which while seemingly mild compared to the excessive heat and violent implosions, can become detrimental over time.

Cavitation is usually recognized by sound. The pump will either produce a “whining” sound (more mild conditions) or a “rattling” sound (from intense implosions) that can sound like marbles in a can. If you’re hearing either of these sounds, you first need to determine the source. Just because you hear one of these two sounds doesn’t guarantee that your hydraulic pump is the culprit.

To isolate the pump from the power take-off (PTO) to confirm the source, remove the bolts that connect the two components and detach the pump from the PTO. Next, run the PTO with no pump and see if the sound is still present. If not, it is safe to assume your hydraulic pump is the problem.

Another sign you may be experiencing cavitation is physical evidence. As part of your general maintenance, you should be inspecting and replacing the hydraulic oil filter"s elements at regular intervals based on the duty cycle of the application and how often it is used. If at any time during the inspection and replacement of these elements you find metallic debris, it could be a sign that you’re experiencing cavitation in the pump.

The easiest way to determine the health of your complete hydraulic circuit is to check the filter. Every system should have a hydraulic oil filter somewhere in-line. Return line filters should be plumbed in the, you guessed it, retu