When your hydraulic system stops working, no matter the cause, it can bring productivity to a grinding halt (both literally and figuratively). Troubleshooting and tracking down the problem will take skill, experience and common sense. There are a few basics that anyone can handle, however. The basics of hydraulic troubleshooting serve as a reminder to keep it simple and take time to do each step. This will save money and time in the long run.  

Preparing for Troubleshooting

Before you even begin the troubleshooting process, it’s important to know what the problem is. This means you have to ask questions before you start. Some basic questions might be:

  • How long has this been happening/When did it start?
  • When did you first notice the problem and what was happening? (startup/shut down/heavy load/temperature change/etc.)
  • Have there been any recent changes to the system, such as maintenance, modifications to the settings, or repairs?
  • When was maintenance last performed?

Once you have as much information as you can gather, pull the hydraulic schematics for reference. It’s important to know that you should not attempt troubleshooting without this! The schematics provide valuable information about flow and pressure in the system.

Common Problems

There are a number of issues that commonly prevent hydraulic systems from working properly, such as an inoperative system or overheating hydraulic fluid. In any basic troubleshooting, it’s key to look at the most typical issues that arise in hydraulic systems first.

System Inoperative

When your hydraulic system is inoperative, there are several things that can be checked. First, you must verify the hydraulic fluid levels and check for leaks, as they can lead to significant loss of hydraulic fluid. Filters are also a common problem because if they are dirty or clogged, they can seriously impact performance. Check your hydraulic lines for restrictions such as collapse or clogging. Be sure you do not have any air leaks affecting the suction line. Also, inspect the pump itself; if it is worn, dirty, or out of alignment, it will affect system performance. The drive can be a source of issues if belts or couplings are slipping or broken. 

Slow Operation

If your hydraulic system is working more slowly than normal, it could be as simple as the hydraulic fluid is too thick, which may be due to cold temperatures or the use of an inappropriate hydraulic fluid. Air trapped in the system can be a problem, as well as restrictions in the line, due to dirty hydraulic filters. Another potential issue is badly worn hydraulic components such as pumps, motors, cylinders, and valves.

Erratic Operation

When a system is operating in an erratic, unpredictable manner, it can be very frustrating. One of the most common causes for this is air trapped in the system or hydraulic fluid that is too cold. Damaged internal components, such as bearings and gears can also be a reason, although it is a bit less common.

Excessive Noise or Vibration

Something that almost anyone who works with hydraulic equipment has experienced is excessive/abnormal noise or vibration. The pump being noisy calls for a 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 informs you that there is air in the fluid. This 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. Noise and/or vibration can also mean you need to make sure the couplings are secure and tight. Keep in mind that pipes and pipe clamps can vibrate if they are not secured properly, so take a moment to check them over if none of the other checks show an issue.

Overheating Hydraulic Fluid

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 primary 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 many 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. Restrictions in the line or dirty filters can result in hot hydraulic fluid or 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 the heat to radiate away from them.

No Fluid Flow

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. Getting your hydraulic system back in working order can be a time-consuming process. At Yarbrough Industries, we understand the importance of having a functional, efficient hydraulic system. We know that downtime is a price that you can’t pay in both money and time. That is why we offer comprehensive hydraulic services on-site troubleshooting and repair. Our team of experienced technicians can work on motors, pumps, valves, cylinders, and systems. 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.

 

Contact us today to find out how Yarbrough Industries can help keep your hydraulic systems operating efficiently.

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There is no time to waste when your hydraulic equipment fails. You have to get it working as soon as possible. There are always three options when it comes to hydraulic equipment – repair, replace or rebuild. How do you know which one to choose?

All three options can be good, but more and more companies are opting to rebuild hydraulic equipment rather than purchasing new components or repairing the existing components. What is a rebuild, and when should you choose that option over repairing or replacing a component? It’s important to make an informed decision the next time you face a hydraulic equipment failure, so let’s look at the options.

Equipment Repair vs. A Full Rebuild

Definitions of a rebuild can vary based on the shop you visit, but typically a rebuild is a piece of equipment that has been used previously and completely reconditioned for further use. Our expert rebuilders at Yarbrough Industries can not only restore a piece of equipment to OEM specifications, they can often exceed the quality of a brand-new machine.

A proper hydraulic equipment rebuild means that it is completely disassembled and every piece is inspected individually. The parts are evaluated for wear, damage, and effect on the overall life of the component. Replacement and reconditioning of parts are performed as needed, the component is reassembled, and then it undergoes a thorough quality and performance testing.

A repair is a process focusing on fixing the individual parts involved in the failure, rather than the overall equipment.

There is also some confusion about the similarity to purchasing used hydraulic equipment. However, used equipment has not generally been refurbished or reconditioned and as an older piece of equipment, maybe closer to a failure.

Pricing Your Choice:

Rebuilds are increasing in popularity every year because they tend to cost less over time.

A rebuild typically costs about half of the price of a new piece of equipment, and this includes components like hydraulic motors and pumps.

While repairs may initially be cheaper, it’s only a matter of time before the equipment fails and repairs are once again needed.

In the long run, rebuilds usually end up being cheaper than repairs and are certainly less expensive than purchasing new replacement parts.

Consider Your Lead Time

Choosing to rebuild hydraulic equipment over purchasing new equipment is often the decision when time is of the essence. A certified rebuild usually involves a much shorter lead time, typically because there is significant time that is spent waiting for replacement parts to possibly be manufactured and then delivered. The longer the wait for replacement parts, the longer machines are down, which creates production cost issues and downtime for employees.

When these issues are factored in, rebuilds often become the most economical option. A rebuilt component, such as a cylinder or motor, can be refurbished immediately, minimizing the downtime of the equipment and staff involved.

Let The Experts Make The Decision Easy

At Yarbrough Industries, we can help you, whether it’s a replacement, repair or rebuild. We are committed to providing your equipment the quality and lifespan you need at a price that you can afford. We evaluate and work quickly so that your company is back in business in no time. We also offer rebuild and repair services for cylinders, pumps, gears, motors, valves and other hydraulic components. We work on motor brands including Eaton, Char-Lynn and numerous others.

Here at Yarbrough, our skilled technicians can troubleshoot, rebuild, repair, install, and maintain your equipment on a preventative maintenance schedule.

We offer mobile services, and our trucks are loaded with the parts and tools needed to keep your equipment running at peak performance. Give us a call today! 

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What Are Mobile Services?

Mobile Services are available to offer our customers various on-the-spot services and ensure we meet their unique needs. Yarbrough Industries’ trucks are fully equipped, and we ensure that we know the full scope of the project before coming to you. Some of the services we provide include welding, cutting metal, line boring, fittings and hoses, small crane work, routine hydraulic maintenance and major hydraulic projects.  

Why Would I Need Mobile Services? 

Sometimes it’s a hassle taking your projects to a shop and then wait in line with other clients. Sometimes, a project can’t be moved due to logistics. Whether it’s not convenient or too difficult, bringing a project to our shop can waste valuable time & potentially cost you money. 

With mobile services, you no longer need to go to the shop; our fully trained technician comes to you. Our mobile service units can carry out different projects effectively and efficiently to ensure you are back up and running in no time. We do routine maintenance on your plant’s hydraulic systems, but we can also do major hydraulic projects at your location if needed. Our trucks can Weld & Cut Metal at your location. Yarbrough’s also does Line Boring at your location.

How Does a Mobile Service Call Work?

We have invested in state-of-the-art tools and equipment as well as employing qualified and experienced technicians. Depending on the particular service you request, our technicians will respond quickly and deliver superior quality. Our trucks are loaded with generator/welders, air compressors, hose crimp machines, fittings, hoses, adapters, cutting torches and small cranes and numerous tools, as well as some of the most common repair parts. When you call, we take the time to determine what will be needed for your project ahead of time to ensure we can be as efficient and effective as possible while we are there.

Get direct access to industry-leading content

This industry moves fast, but you can move even faster if you’re up to date on trends, technical developments, and best practices. The Yarbrough Industries blog is a go-to source for valuable, timely and detailed information. Sign up to ensure that you don’t miss a single post.

Many detractors sneer at the idea of hydraulic efficiency, right-sizing components, proper system design and modern technology can go a long way to achieving system efficiency.

Piston pumps, such as this Hengli America, are some of the most efficient hydraulic pump designs available.

“Hydraulic efficiency” is a term alluding similar sentiments to “exact estimate” or “scientific belief.” It’s not that hydraulic efficiency is an oxymoron, per se, but these aren’t traditionally two words that make sense shoulder to shoulder. If efficiency was your top benefit on the list of machine requirements, fluid power wouldn’t have been on your shortlist of options, at least in the past half-century or longer.

Efficiency is a word now more commonly familiar to us, thanks to the escalation of green values—especially those defining the way we use natural resources. No longer can we take a limitless and inexpensive source of energy for granted, nor can we abuse the dirty sources of inexpensive energy at the expense of our precious environment. We must take full advantage of our energy resources to achieve the work required for maintaining our standard of living while reducing associated waste along the way.

What is efficiency?

I define efficiency as work-in minus work-out. Essentially, it’s the differential between the energy your process requires and the energy input required to achieve that process. Your process could be stamping, rolling, injecting, moving, pressing or any other mechanical function capable of being achieved in a rotational or linear motion. If you’re running a punch press, for example, the machine efficiency is defined as the current draw of the pump’s motor minus the combined force and velocity of the punch die.

Most machines are designed to convert energy from one form to another, which can sometimes occur multiple times. Because of the Laws of Thermodynamics, you cannot change energy from one form to another without creating waste energy, and this is a fact regardless of the energy transformation taking place. In the case of a hydraulic machine, you must convert electrical energy to mechanical energy within the electric motor, resulting in partial waste. Then you must convert mechanical energy into hydraulic energy within the pump, resulting in partial waste. Then you must convert hydraulic energy back into mechanical energy at your cylinder or hydraulic motor, resulting in partial waste.

The amount of energy wasted in the above example could be staggering, especially if you’re using an old machine with old components. Let’s say you have a 10-hp electric motor—and keep in mind electric motors are rated on power consumption, not power output. Your old motor might have an efficiency of 85%, meaning it will produce 8.5 hp at its shaft, the other 1.5 hp being wasted as pure heat.

In your old power unit, you have a worn and tired gear pump. When new, a gear pump is lucky to have 80% efficiency, so I’ll be generous to throw 75% at this example since gear pumps become less efficient over their lifetimes. So this pump can convert only 6.4 of the motor’s 8.5-hp shaft output into usable hydraulic energy. The rest of the energy is, you guessed it, wasted as pure heat. We’ve now lost 36% of the electrical energy inputted, and we haven’t even done anything yet.

Just to be intentionally derisive, I’m going to choose a hydraulic motor as our actuator; a gerotor motor to be exact. These motors come at a modest price and perform at a modest level. They were a clever design back in the day, but have high leakage to lubricate the myriad components, and they leak even more if you operate them outside their optimum torque and speed curve. Leakage, I should note, is a designed element of most hydraulic components, based on gaps and clearances with internal moving parts, which is required to lubricate that component. More moving parts or higher clearances mean more leakage, and I should further note, any fluid lost to leakage carries with it pure heat equal to the pressure and flow of the leakage.

Now that I’ve blasted gerotor motors, I’ll back it up by saying they’re often incapable of reaching 80% efficiency. There are some versions of these “orbital” motors, like the disc valve variant, which can be close to 90% efficient, but it would be only within a tiny window of flow and pressure. I’ll stick with 80% for this example, which is generous. With the 6.4 hydraulic horsepower we have in our system, we’re left with 5.1 hp at the hydraulic motor’s shaft.

Why use hydraulics in the first place?

So with barely half of our input energy making its way to the output stage, it’s easy to see why I’m dubious of “hydraulic efficiency.” So why use hydraulics when we could have powered our machine straight from the electric motor and take advantage of 8.5 hp instead of 5.1? In that answer lies the reason hydraulics are awesome; with $300 worth of valving, you can infinitely vary torque and speed, and reverse direction. Our electric motor would require sophisticated electronic control to achieve the same features.

To be fair, I’m using one of the worst-case examples for hydraulic efficiency. Not only are there more efficient components available than gear pumps and orbital motors, but there are also ingenious approaches to using hydraulic components. Furthermore, recent advances in electronic control have not ignored the fluid power industry, and there are some tricks to further improve hydraulic efficiency.

Invest in better technology

Pressure compensated pumps are set to a particular standby pressure, and when this pressure is reached, the pump reduces flow until downstream pressure drops below that standby pressure. Image courtesy of CD Industrial Group

I can’t stress enough that a hydraulic machine is really just an energy conversion device, and when you can convert your input energy into usable force with as little heat waste as possible, you’re on the right track. A pump converts the mechanical energy of the prime mover into hydraulic energy in the form of pressure and flow. If I were to recommend one component you blow the bankroll on, it would be the pump.

A piston pump, especially a high-quality one, can be 95% efficient at converting input energy into hydraulic energy. Not only does this pump provide 27% more available hydraulic energy than our old gear pump, it creates 80% less waste heat than it, reducing or eliminating cooling requirements.

Not only does an efficient pump help, but an efficient design also works wonders. If you have a fixed displacement pump on flow control, any unused fluid is wasted as heat. For example, take even our 95% efficient fixed piston pump, giving us 9.5 GPM out of a theoretical 10 GPM. If your downstream priority flow control valve is set to 5 GPM, 4.5 GPM is bypassed to the tank. However, all of the 9.5 GPM is still being created at full system pressure, and what’s dumped into the tank is lost as heat. So now our 95% efficient pump is helping create a 50% inefficient system.

A load-sensing pump will provide only the pressure and flow required of the circuit and actuator, with only a few hundred psi worth of pressure drop as the waste by-product. Image courtesy of CD Industrial Group

To get around this, pressure compensation was created. A pressure-compensated pump is set to a particular standby pressure, and when this pressure is reached, the pump reduces flow until downstream pressure drops below that standby pressure. For example, if you have a 10 GPM pump set at 3,000 psi, and flow is restricted below 10 GPM, the pump will reduce its displacement to exactly match the downstream flow and pressure drop at 3,000 psi. Essentially, the pump only produces the flow being asked for, no more, but always at 3,000 psi.

But what if we only want 1,000 psi for a particular operation? Well, you could use a pressure-reducing valve, but the pump is still producing 3,000 psi, so you’re not saving any energy. To remedy this, the load-sensing pump was invented. A load-sensing pump has an additional compensator that is plumbed downstream of the metering valve. This configuration allows it to measure load pressure and compare it to compensator pressure. The result is the pump will provide only the pressure and flow required of the circuit and actuator, with only a few hundred psi worth of pressure drop as the waste by-product.

The use of variable speed technology can dramatically increase hydraulic efficiency. Here, the new Green Hydraulic Power units use Siemen’s SINAMICS variable speed servo pump drive to increase efficiency by up to 70%.

Recent advancements in control technology have resulted in a similar concept of pressure and flow management, but using a combination of fixed displacement pumps, servo or VFD motors and pressure transducers. The pressure transducers measure the pressure after the pump and after the metering valves, and PLC gives the signal to rotate the pump at a speed only fast enough to achieve the desired pressure and flow. It’s quite an advanced technology and has progressed to the point a pump could hold a stationary load and rotate fractional speed just to compensate for leakage. Another advantage to this technology is that the motor doesn’t even turn when no energy is required, and then again only with the energy required by demand of the hydraulic system.

Aside from choosing efficient pump designs, using efficient hydraulic actuators is the next best place to continue. Not much can be said of hydraulic cylinders, because most are close to 100% efficient already, depending on sealing technology. But just like with your hydraulic pump, the hydraulic motor has many variations, each with its own contribution to overall efficiency.

 

Ranking popular hydraulic motors in terms of efficiency, they range from the radial piston, axial piston, vane, gear and orbital, with efficiencies around 95, 90, 85, 80 or less, respectively. Of course, these motors would have the same ranking in cost, so the adage of “you get what you pay for” applies here. Other than just choosing an efficient motor design, there isn’t much you can do to enhance efficiency, other than eliminating return port backpressure and applying motors with the same load-sensing techniques described with pumps.

So for the most part, hydraulics is not an efficient technology. But neither are gasoline-powered cars, and millions of those are sold every day because there is no better option for their task. Regardless, efficiency in hydraulics is progressing, and advancements in materials and technologies will further that. As long as you are aware of what it takes to create “hydraulic efficiency,” the term won’t seem curious like “seriously funny” or “virtual reality.”

Get direct access to industry-leading content

This industry moves fast, but you can move even faster if you’re up to date on trends, technical developments, and best practices. The Yarbrough Industries blog is a go-to source for valuable, timely and detailed information. Sign up to ensure that you don’t miss a single post.