Hydraulic system maintenance framework

Lack of hydraulic system maintenance is the leading cause of component and system failure, yet most maintenance personnel do not understand proper maintenance techniques of a hydraulic system. The foundation to perform proper maintenance on a hydraulic system has three areas of concern: corrective, preventative and predictive.

Corrective Maintenance

It takes place following failure or damage, that is, it only occurs when there is an error in the system. This maintenance entails the following consequences:

  • Unplanned shutdowns
  • At production, it affects production lines
  • It means costs due to not budgeted repair and replacement
  • The time the system will be out of operation is not predictable

Preventative Maintenance (PM)

Preventive Maintenance of a hydraulic system is very basic and simple and if followed properly can eliminate most hydraulic component failure. Preventive Maintenance is also a discipline and must be followed consistently to obtain results.

Consider a PM program as being “performance oriented” rather than being “activity oriented.” Many organizations have good PM procedures but do not require maintenance personnel to follow them or hold them accountable for the proper execution of these procedures. To develop a good preventive maintenance program, follow these steps:

         1.  Identify the system operating condition.

  • Does the system operate 24 hours a day, 7 days a week?
  • Does the system operate at maximum flow and pressure 70% or better during operation?
  • Is the system located in a dirty or hot environment?
  • Identify the system operating condition.

2.  What requirements does the Equipment Manufacturer state for Preventive Maintenance on the hydraulic system?

3.  What requirements and operating parameters does the component manufacturer state concerning the hydraulic fluid ISO particulate?

4.  What requirements and operating parameters does the filter company state concerning their filters ability to meet this requirement?

5.  What equipment history is available to verify the above procedures for the hydraulic system?

As in all Preventive Maintenance Programs it’s a good practice to write procedures required for each PM task. Steps or procedures must be written for each task and they must be accurate and understandable by all maintenance personnel from entry level to master technicians. Preventive Maintenance procedures must be a part of the PM Job Plan which includes

  • Tools or special equipment required performing the task.
  • Parts or material required performing the procedure with store room number.
  • Safety precautions for this procedure.
  • Environmental concerns or potential hazards.

A list of Preventive Maintenance Task for a Hydraulic System could be:

Hydraulic system preventative maintenance task list

Preventive Maintenance is the core support that a hydraulic system must have to maximize component life and reduce system failure. Preventive Maintenance procedures that are properly written and followed will allow equipment to operate to its full potential and life cycle. Preventive Maintenance allows a maintenance department to control a hydraulic system rather than the system controlling the maintenance department. You must control a hydraulic system by telling it when you will perform maintenance on it and how much money you will spend on the maintenance for the system. Most companies allow the hydraulic system to control the maintenance on them, at a much higher cost.

Predictive Maintenance
Predictive maintenance consists of determining the real technical conditions (mechanical and electrical) of the equipment examined, while it is in full operation.

The cause of many breakdowns couldn’t have been prevented with routine maintenance, but could have been caught with a predictive model. In many cases, it doesn’t make sense at all to do PMs from both a cost AND a time perspective. Regarding the preventative maintenance model, there are 3 critical factors in preventative maintenance that you must consider:

  1. How bad is the worst-case scenario?
  2. What is the likelihood of a breakdown?
  3. How much will it cost?

So, how often should you PM? Should you do it every 6 months, every 8 months or maybe every 4 months? This is something that is a bit controversial and needs to be looked at from a cost perspective. At the end of the day, PMs can be expensive if you are over PMing something, but it can help prevent critical failures. However, you also need to consider the fact that even if you PM something, that doesn’t necessarily prevent all failures. You need to make sure you are PMing the right thing and the correct frequency.

So, which is the better, predictive maintenance or preventive maintenance?

At the end of the day, ideally you would like to move from reactive to predictive. You also need to be able to tell when something is close to breaking down, or when the efficiency of that machine goes down to a point where it makes more financial sense to replace a component.







Process Cooling Systems/Bearing Lube Cooling Systems/Turbine Lube Systems

Every industry has its unique challenges, but virtually all industries share the goals of increased machine uptime, reduced maintenance, improved safety, energy savings and lower total cost of ownership. Having a reliable machine lubrication system is vitally important. Bearing life is often much better when the bearing is kept clean and well lubricated. However, many applications make good maintenance difficult.

image of custom process cooling lubrication system

Process Cooling System
Process cooling systems provide cooling fluid to a process function.  The process starts with the reservoir; it provides some heat transfer, however the majority of cooling starts with heat exchangers. Heat exchangers remove heat from a system by transferring the heat to another media (water or air). Types of heat exchangers may include fan, shell & tube, plate or refrigerated and vary in cost and efficiency. Typically, multiple pumps are used to prevent a single failure from shutting down the system.

Bearing Lube / Cooling System

lubrication system featuring a bearing skid system

image of bearing lube skid

Bearing lubrication and cooling skids provide a source of cool clean oil to remove heat from bearings.  This extends the life of the system and prevents cost breakdowns.  Lube systems typically have the following:
                Lube pump and optional backup lube pump
                Heat exchanger
                Gravity return ports
                Low and kill Level switches
                High and kill temperature switches
                Output pressure switch and gauge

Turbine Lube System

Turbines require bearings for support during operation. Each of these bearings are supplied with hydraulic oil for lubrication. Hydraulic Lubrication systems are crucial if turbines are to have a long and productive life. However, the oil itself needs to be kept at the right temperature for effective lubrication. EHA-manufactured hydraulic lubrication systems are designed to keep the oil at the right temperature. They typically feature the following components:

  • Lube Reservoir that contains the cooling oil for a turbine based pump.
  • Electrical emergency backup pump that provides pre-startup lube flow and backup flow in the case of a main turbine pump failure.
  • Low & high pressure switches Learn more about pressure switches for lubrication systems.
  • Dual Lube filtration with dirty filter indicators – Lean More
  • Pressure gauges before and after main filtration give a visual indication of the pressure
  • High Temperature switch and gauge
  • Water-to-Oil heat exchanger with water saving and temperature regulation valve
  • Lube temperature gauges before and after heat exchanger
  • Oil sample port - for easy lab sampling of oil 
  • Fluid Level indicator
  • Turbine Pressure regulator
  • Turbine suction and gravity return ports

Turbine lubrication maiuntenance system

image of turbine lubrication system



EHA - Advantages of using Accumulators in Hydraulic Systems

EHA Accumulator Rack
Energy storage
An essential function of accumulators is their ability to store energy. Particularly in cyclic or varying operations, accumulators discharge in times of high demand and recharge during periods of low demand. They are often used to supplement pump flow during peak demand. Without an accumulator, the pump and motor must be sized to handle peak power requirements even if maximum power is only required momentarily. Benefits include:
  • Smaller pump that recharges the system during periods of slack demand.
  • Smaller motor; a total system that demands less energy & heat and costs less.
Emergency backup
Accumulators can maintain a high-pressure charge almost indefinitely and serve as an emergency power source should a machine lose electric power or a pump fails. Benefits include:
  • Provides the necessary flow and pressure to retract a cylinder.
  • Close a valve.
  • Move a machine to a safe position until power is restored or the malfunction is corrected.
  • If a lubricant pump fails, the accumulator maintains pressure until the machine stops or a secondary pump restores flow.
Vibration and shock reduction.
Mounting a small accumulator near the outlet of the pump can absorb pulsations, minimize vibration and provide smoother operation. Also, adding an accumulator into the return line of machines can mitigate shock. Benefits include:
  • Cushioning "water" hammer effect
  • Prevent damage to sensitive components and extend component life and lower maintenance costs.
  • Reduce overall hydraulic system noise levels resulting in quieter machines.
Leakage & temperature compensation
An accumulator can maintain constant pressure even if fluid slowly leaks internally past piston seals or valve clearances and compensate for temperature-related pressure differences in a closed hydraulic system. Only when circuit pressure drops below preset limits does the pump fire up and recharge the accumulator.
Faster response
Bladder and diaphragm accumulators have virtually instantaneous response and can quickly supply fluid to valves and improve their performance. Accumulators can also immediately meet peak flow requirements.

EHA Fluid power Repairs

When the time comes and you experience cylinder failure, the decision must be made whether to buy new or repair. The benefits of repairing include:

  1. Shorter lead times
  2. Significant cost savings over new cylinders
  3. The ability to identify the cause of failure

Short Turnaround Time
EHA offers quick turnaround on cylinder repair as well as emergency repair service. We understand that breakdowns can occur at any time and when they do you are robbed of your valuable production time and profit. Our in-house machining capabilities are made up of multiple machining centers with experienced technicians They are qualified to rebuild your cylinder to a “better than new” condition. We have a fully equipped repair center with the necessary equipment for repairing cylinders of all sizes wide range of industries.

Save by Repair
Repairing a cylinder can save you approximately 40-50% the cost of new. Although a large portion of the savings comes as a direct result of using many of the existing parts in the repair process, this will not compromise the quality or performance of a repaired cylinder. We test every cylinder we repair. Our testing standards will assure you that your cylinder will be ready for immediate use when it leaves our facility.

Save With Investigative Information
Cylinders sent in for repair receive a thorough inspection at the start of the repair process. During this phase, our technicians check for any stress that may have been placed on the unit from excessive side loads, improper mounting, fluid contamination or defective seals. The information gathered during our inspection may help you adjust and correct issues with your related equipment to extend the life of your cylinders. Simply purchasing new cylinders may not address the specific issues that may lead to repeat failure of the new product.


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Balluff new Emergency Stop Device

Emergency Stop Device
Compact housing for simple installation on various machines and equipment

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Balluff True Color Sensor

True Color Sensor BFS 33M
Balluff’s true color sensor uses white LEDs to produce a greater color spectrum evaluation

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Balluff Magnetically coded safety switch

Magnetically coded Non-Contact safety switch
Non-contact magnetically coded safety switches are outstanding for monitoring guard doors-especially in environments where contamination or dust is expected.

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Balluff RFID Non Coded Safety Switch

RFID Coded Non-Contact Safety Switch
Tamper resistant, wear free access protection – with a wide range for installation and utilization.

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Balluff Optional Latching Force safety switch

RFID Coded Non-Contact Safety Switch with Optional Latching Force

Tamper-proof, wear-free access security.

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New Literature


Ballluff Industries Literature          Balluff Systems 1          Balluff Control Systems

                                                                   Steel and Metallurgical                          O-Link for Machine Builders                    Control Systems Architecture:
                                                                              Industry:                                                                                                          Common Layouts for
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gas spring is a type of spring that, unlike a typical mechanical spring that relies on elastic deformation, uses gas contained within an enclosed cylinder sealed by a sliding piston to pneumatically store potential energy and withstand external force applied parallel to the direction of the piston shaft. Much larger gas springs are found in machines that are used in industrial manufacturing, i.e. the press tooling industry, where the forces they are required to move are very heavy.

Top Tips for Selecting and Installing Gas Springs for Lifting and Lowering

1. Collect the data you need to size your gas spring properly.

  • Locate the center of gravity (M) for your hood or door, typically the center point between the system’s pivot point and handle. This can also be determined from your CAD drawings for more complex doors and hoods.
  • Measure the dimensions of the door or hood; alternatively, your CAD drawings can provide you with the door or hood measurements in all three dimensions.

  • Find the radius measurement to your center of gravity (Rw) from the pivot point, located in Step 1.

  • Next, measure the radius of your hand force, which is the distance between your pivot point and the handle (RH)
  • Find your starting angle (aM)—the angle created between the horizontal level and RM when your hood is  closed—by checking it on your CAD drawing or measuring it directly on your application.
  • You’ll also need the opening angle (a), which is the total angle of rotation from when your hood is closed to when the hood is open.

  • Finally, measure your hood weight (m), which may be found in your CAD dat a. Without CAD, this is easily accomplished by using a spring scale during lifting. Note that the distance used for measuring the weight needs to be scaled  to RM for an accurate number (multiply measurement by RH and divide by RM).

2. Decide how many gas springs you will be using.

If your hood is wide or cumbersome for any reason, it is recommended that you use two gas springs, one on
either side. This will also prevent you from adding lateral forces into your calculation, which can greatly change
the size and capacity of your final choice.

3. Consider special conditions posed by your environment.

Equipment that operates in high or low temperatures, around abrasive chemicals, or in a place with excessive
dust and dirt, may require special seals, oils, etc. So, at this point, check the manufacturers’ catalogs for specific
characteristics of each gas-spring series they have available. In addition, most manufacturers provide help in
making the right decision. For example, ACE Controls provides an easy-to-use online calculator that asks for
all of the above information and then helps you make the right selection for your application’s needs. For more
complicated applications, ACE engineers are ready to help you specify the right product.

4. Mount the gas spring correctly.

Be sure that the flap hits the end position without end damping. A small amount of oil has been placed in the
pressure tube to assure that the seal is properly lubricated and that the end position is hydraulically damped.
Now, mount the gas spring with the piston rod down. This helps to reduce the extension velocity during operation
and makes sure that the piston dives into the oil.

5. Adjust the pressure in your gas spring for proper usage for your application.

Adjustments are often needed when one of two things happen—either the designer didn’t know the correct
data during the time for specifying the gas spring, or the machine design changed after the spring specifications
were decided upon. If your hood is being pushed back open rather than staying closed, you will have to de-gas
the spring.

To adjust the gas pressure and extension force, you’ll need to remove the gas spring from the hood. Screw the
de-gas adjustment tool onto the gas spring. Tap the tool to release excess gas, then reattach the spring to the
hood. You can also purchase fully charged gas springs and find the appropriate force by bleeding the gas springs
down if you don’t have all of the necessary information for sizing.

6. Focus on your application.

The keys to selecting and installing gas springs are application specifications and uniqueness. For example,
in an underground distribution system, easy access for servicing is critical. By incorporating two gas springs
to lift heavy covers (mounted with large supply systems), maintenance and repeated operation become easy.

Another application requires gas springs to aid in the prevention of injuries during maintenance work on
harvesting machines. Proper gas-spring selection is key, because they need to be stable under rough operating
conditions. Once again, proper sizing is important when used on helicopter doors, such as those operated for
rescue operations. The proper component provides a defined retraction speed and secure engagement of the
door lock. An integrated end position damper is added to allow gentle closing of the door while reducing wear.



Rexroth Bosch HPU article

Rexroth Bosch Group White Paper Article on Designing  HPUs for Hydraulic Systems

Download full Whitepaper
8 minute read



Applications for power units span the spectrum of fractional horsepower requirements to those incorporating drives using 100’s of horsepower. From left: Standard, pre-engineered power unit CytroPac; configurable GoPak power unit; typical custom power unit for industrial use; large, complex custom power unit. New capabilities and power unit designs provide many new options to machine and hydraulic system designers.


Environmental or other application-specific requirements, such as high altitude or required certifications, can drive one-of-a-kind solutions. Well-designed Hydraulic Power Units, whether large custom unit or a compact standard unit (including units built into a machine frame), consider all aspects of an application.


Complexity in applications or specification may require complex control packages nearly the same size as the hydraulic power unit. A well designed and built power unit not only achieves functional criteria but can also be an attractive addition to the production floor. Full-featured, complex hydraulic power units should be designed toward functionality and robustness. A clean design must also consider periodic maintenance and service when needed, for example platforms to contain fluid spills, or easy access for replacement of filters.

7 Considerations

  1. Overall Power and Force Requirements
  2. The Operating Environment and Location
  3. Serviceability / Service Life
  4. Noise
  5. Energy Efficiency
  6. Cost
  7. So What About Industry 4.0 and “The Internet of Things?”


With all of the choices facing an engineer designing or selecting a power unit, the fact is this: Designing a power unit can be daunting. Not only must the successful designer develop a robust solution, one that will be capable of producing the “power” required over a long service-life, he or she must also consider plant-floor environments, safety, regulatory requirements, serviceability and maintenance, noise, energy efficiency, and sometimes even IoT-readiness. All of these considerations can influence the lifetime cost.

You’ll need to consider a partner who can provide support wherever your power unit might end up in operation and who is familiar with the safety requirements. IFP/EHA is your solution partner. Visit our previous blog post: Expertise in Hydraulic Power Units



Manufacturing, Sales & Service

IFP Group of Companies consists of Iowa Fluid Power, Electro-Hydraulic Automation (EHA) and Innovative Fluid Power. EHA, located in Cedar Rapids, Iowa is our world-class manufacturing facility specializing in hydraulics, pneumatics and motion control systems.

Hydraulic power units have been manufactured by EHA for the past 35 years for Industrial and Mobile market applications. We offer:
•    Standard base-pak pre-engineered fixed and pressure compensated power units.
•    Custom power units to thousands of horsepower.
•    Complete systems from fully automated electronic control systems

Through our many supplier affiliations at IFP we can provide the required components to build custom power units designed by EHA’s engineers using electric, gas or diesel prime movers; also experience with (natural & LP) gas applications.

Base-Pak Power Units

•    Standard Vertical Units from 3 to 30 Gallon.
•    Standard Horizontal Units from 10 to 100 Gallon.
•    Standard layouts provide quick delivery in single pieces or large quantities.
•    EHA's volume and manufacturing methods will give you the hydraulic flow and pressure that you need at a price
      you can afford.    

EHA manufactured power pak HPU

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Custom Power Units

•    5 gallon to 5000 gallons.
•    Depending on customer preference, components from most of the different major fluid power manufacturers can be used.
•    Experienced engineering staff provides quick design turnaround and complete documentation.
•    From one unit to one hundred units, we can quickly deliver high quality, long life systems that will power your hydraulic
      machines for years to come.
      Complex HPU

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Complete Systems

  • Hydrostatic and Open Loop hydraulic systems along with
    the electronics and the know-how to put together the system that you need.
  • Hydraulic systems for a single machine or "central" hydraulic systems to power your entire plant.
  • From thousands of horsepower to just a few, EHA can deliver the most efficient up-to-date system that your
    application demands.
  • EHA can provide electrical and electronic controls either to interface with your other in-plant systems or as a
    stand-alone machine.

    EHA manufactured cokple system HPU

Offshore Power Units

  • IFP provides an extensive range of hydraulic components from the world’s leading manufacturers.
  • EHA designs, manufactures and supplies customized equipment for the offshore industry.
  • Our knowledgeable team is available to answer your questions, whether technical or regarding product
  • Optimal equipment performance in extreme working conditions, like the offshore industry, is our main
    consideration for all our solutions.

    EHA manufactured Offsore power unit

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Prime Movers (Gas, Diesel or Electric Engines)

EHA Prime mover - gas powered EHA Prime Mover - Diesel Powered  Electric Motor Powered                        
  • EHA has engineers capable of specifying the HPU components and prime mover type based on torque, speed, and power requirements of the hydraulic power unit and system requirements.
  • Prime movers are fully load tested in one of our test cell .
  • The completed prime mover is then painted and prepared for shipment
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Whether you have very specific needs or you just looking for a high quality standard solution, we provide complete custom built Hydraulic Power Units (HPUs) for every industry, situation and requirement.

Power Unit line card


Clippard efficient pneumatic systems

Clippard's easy-to-understand white paper offers a step-by-step approach that takes the guesswork out of pneumatics, and at the same time, provides the necessary information to tailor the design for your specific needs. Clippard's standard product line includes pneumatic cylinders, a complete line of electronic and air valves, precision flow control products, manifold assemblies and more. Custom alterations to standard products are also welcomed.

Whitepaper: https://bit.ly/2GgFMMe