Troubleshooting Charts for Eight Categories of Hydraulic Problems (2024)

Jul. 12, 2023

Troubleshooting charts for eight categories of hydraulic problems

The following troubleshooting guides cover five categories of hydraulic problems.Possible causes and remedies are listed for each type of trouble.Causes are listed in order of probability; remedies are listed adjacentto the associated cause.

Abnormal / exessive noise

Source/Symptom: Pump

Possible Problem Recommended Action Cavitation

Replace dirty strainers.

Clean clogged inlet line.

Clean reservior breather vent.

Change to proper pump drive motor speed.

Air in fluid

Tighten leaky inlet connection.

Fill reservoir to proper level.

Bleed air from system.

Replace pump shaft seal.

Coupling

Tighten coupling.

Check condition of seals and bearings.

Pump worn or damaged Repair or replace.

Source/Symptom: Motor

Possible Problem Recommended Action Coupling misaligned or loose

Realign coupling.

Check condition.

Motor worn or damaged Repair or replace.

Source/Symptom: Mechanical vibrations

Possible Problem Recommended Action Misaligned, loose coupling

Realign coupling and remove any unneccessary clearances.

Vibration of pipes

Tighten pipe clamps and add more clamps where necessary.

Source/Symptom: Relief valve

Possible Problem Recommended Action Improper setting

Install pressure gaugeand adjust to correct valve setting pressure. Make sure setting is not too close to operating pressure or to another valve setting.

Valve worn or damaged

Repair or replace.

Excessive Heat

Source/Symptom: Pulp

Possible Problem Recommended Action Pump worn or damaged Repair or replace.

Source/Symptom: Relief

Possible Problem Recommended Action Incorrect setting

Install pressure gauge and adjust to correct setting pressure.

Source/Symptom: Flow losses between pressure and return sides

Possible Problem Recommended Action Pressure set improperly

Set pressure to the diagram raiting.

Defective valve function or damaged seals

Repair or replace it.

Source/Symptom: Insufficient cooling

Possible Problem Recommended Action Cooling water system unavailable

Make cooling water available.

Deposits in cooling water system

Clean cooling water strainer and equipment.

Source/Symptom: Tank heater

Possible Problem Recommended Action Heater on too much

Check program for proper command.

Check disconnect for proper operation.

Source/Symptom: Viscosity too low

Possible Problem Recommended Action Oil damaged

Drain and refill with fresh oil.

Water contamination

Find and repair water source, then drain and refill with fresh oil.

Improper oil

Drain and refill with fresh correct oil.

Incorrect Flow

Source/Symptom: No flow

Possible Problem Recommended Action Pump not receiving fluid

Replace dirty strainers.

Clean clogged inlet line.

Clean reservoir breather vent.

Incorrect Pressure

Source/Symptom: No pressure

Possible Problem Recommended Action Dirty pump strainers

Replace.

Clean clogged inlet line.

Pump motor not operating

Repair or replace.

Pump-to-drive coupling sheared

Repair and align coupling.

Pump motor rotation incorrect

Reverse rotation.

Directional valve in wrong position

Check position of manually-operated valves.

Check electrical circuit for solenoid-operated valves.

Entire flow passing over relief valves

Adjust relief valve setting.

Damaged pump

Check for damaged pump or drive.

Replace and align coupling.

Source/Symptom: Low pressure

Possible Problem Recommended Action Reducing valve set too low Adjust. Reducing valve worn or damaged Repair or replace. Relief valve or unloading valve set too low Adjust. Variable displacement mechanism malfunctioning

Check pump compensator.

Repair or replace.

Pump, valve, motor, cylinder or other component worn or damaged Repair or replace. Water contamination Drain, fluss and refill

Source/Symptom: Erratic

Possible Problem Recommended Action Air in fluid

Tighten leaky connections.

Fill reservoir to proper level.

Bleed air from system.

Source/Symptom: Excess pressure

Possible Problem Recommended Action Reducing valve or unloading valve set too high

Adjust

Variable displacement mechanism

Check pump compensator.

Repair or replace malfunctioning.

Faulty Operation

Source/Symptom: No movement

Possible Problem Recommended Action No pressure or flow See troubleshooting guides for incorrect flow and incorrect pressure. Limit device / sequence device inoperative or improperly set

Check mechanical, electrical and/or hydraulic limits and sequence devices.

Adjust, repair or replace.

Mechanical bind not operating Locate and repair bind. Cylinder or motor damaged Repair or replace. Low flow

See troubleshooting guide for incorrect flow.

Source/Symptom: Slow movement

Possible Problem Recommended Action Fluid viscosity too high

Fluid may be too cold or dirty.

Check heating/cooling system.

Change to clean fluid of correct viscosity.

Insufficient pressure See troubleshooting guide for incorrect pressure. Lack of lubricant Lubricate machine ways or linkage. Cylinder or motor damaged Repair or replace.

Source/Symptom: Erratic movements

Possible Problem Recommended Action Erratic flow See troubleshooting guide for incorrect flow. Air in oil See troubleshooting guide for air in oil. Improper pressure See troubleshooting guide for incorrect pressure.

Foaming Oil

Source/Symptom: Tank

Possible Problem Recommended Action Oil level in tank too low Add oil as required.

Source/Symptom: Suction line

Possible Problem Recommended Action Crack of leaking suction line Repair or replace.

Source/Symptom: Improper or degraded oil

Possible Problem Recommended Action Inadequate anti-foaming agent Replace with proper oil.

Directional Control Valve Position not Changing

Source/Symptom: Coil not picking up

Possible Problem Recommended Action Electric failure Fix electric failure and check mechanial spool motion.

Source/Symptom: Valve spool stuck

Possible Problem Recommended Action Impurities between spool and bore Replace valve if necessary. Throttle set too tight between the main and pilot valve of the two coil solenoid valve Set the throttle at the correct rating.

Source/Symptom: Proportional valve not responding

Possible Problem Recommended Action Valve not receiving set value from program Locate and fix electric failure. Set value received but valve not responding Replace the proportional valve.

Computer Alarm Messages

Computerized control systems usually have alarm screens which record alarm messages. The following table lists recommended actions to take to resolve common hydraulic alarm.

Alarm Message Recommended Action Pressure filter blocked (identified by pump) Replace old filter with new filter insert. Pressure filter blocked for circulation pump Replace old filter with new filter insert. Circulation/Filter pump fault MCC Motor output gives alarm to control desk if that pump is not running. Circulation/Filter pump stopped with main pumps running Check circulation/filter pump for problems. Hydraulic unit temperature high

Check cooling pump operation.

Check the cooler water strainer.

Check water thermostat operation.

Check that none of the pressure relief valves were set too low. If required, correct the setting.

Return filter blocked Replace old filter with new filter insert.

Hydraulic oil level low

Hydraulic oil level low - pumps stopping

Determine what is causing the drop in oil level. Add clean oil. The pumps will stop automatically if the level drops to the shutdown level. Pump fault MCC or standby pump fault MCC (identified by pump) Motor output gives alarm to control desk if that pump is not running.

For more information on fluids safety and troubleshooting, contact your Valmet representative for training options.

What Are the Most Common Causes of Hydraulic Cylinder Failure?

Hydraulic cylinders are the sometimes forgotten, often overlooked muscles that provide functionality to a wide range of mechanical and industrial equipment and applications. The massive amount of power that results from pressurized fluid flowing into and out of a well-engineered and meticulously manufactured hydraulic cylinder are mission critical components in many different industries such as construction, aircraft support and maintenance, waste management and recycling, railroad operations, manufacturing, shipping and the military—the list goes on. Despite the inherent power and functionality of hydraulic cylinders, they still require regular maintenance and sometimes in order to perform as specified for the applications in which they are used. Improperly maintained hydraulic cylinders can and ultimately will fail, sometimes with catastrophic results. Here are the most common causes of hydraulic cylinder failure.

Contaminated Fluid

Contaminated fluid in a hydraulic system is one of the most common causes of hydraulic cylinder failure. Foreign particulate matter that is inadvertently introduced into the hydraulic fluid can scratch and score the interior of the cylinder. Other liquid contaminates can eat away at critical seals and fittings. In both cases, the contamination of the hydraulic fluid results in a significant degradation of the cylinder’s operational efficiency.

Damaged Seals

The seals in a hydraulic system can be damaged by physical abuse or, as mentioned previously, by contaminated fluid. A damaged seal will affect the ability of the cylinder to maintain the correct internal operating pressure, which in turn impacts the efficiency of the device. Unless the damaged seals are replaced, performance degradation increases over time as the seal damage becomes more pronounced.

Hydraulic Cylinder Side Loads

Hydraulic cylinders are designed to apply force along a specifically intended axis that is aligned with the cylinder itself. In other words, the bi-directional force of the cylinder occurs on a vector defined by the positioning of the cylinder. In a proper hydraulic cylinder installation, the cylinder is installed depending on the intended direction of the desired force vector.

However, hydraulic cylinders are often installed in such a way that forces are applied on a perpendicular axis to the intended direction of movement. This is called side loading, which places unintended strain on all of the components of the hydraulic cylinder. Excessive side loading can result in the catastrophic failure of a hydraulic cylinder. Moderate side loading will accelerate the deterioration of the components of the cylinder, ultimately reducing the lifespan of the device. This is one of the most damaging types of hydraulic cylinder failure.

Piston Damage

Piston damage is caused when the nut or piston retaining device loosens over time. Piston damage occurs from a number of causes. First, like any piece of mechanical equipment, pistons will ultimately wear out. Also, as discussed previously, contaminated fluid or side loading can also result in piston damage. Depending on the load placed on the hydraulic cylinder and the severity of the piston damage, at some point the cylinder will fail completely, resulting the complete loss of power from the device.

Cylinder Pressure

In order to perform according to design specifications, the fluid in a hydraulic cylinder must be maintained at a precise and closely controlled internal pressure. Pressure variations above or below design specifications will have a significant impact on the performance of the device. The pressure should be monitored on a regular basis and adjusted to comply with the manufacturer’s specifications.

Additional Causes of Hydraulic Cylinder Failure

In addition to the problems defined above, there are several other less common but nevertheless critical causes of hydraulic cylinder failure.

The first is physical damage, typically caused by an accident of some sort. External damage to a hydraulic cylinder can create a wide range of problems, all of which will degrade the performance of the device if not destroy it completely. Examples include cracks in the cylinder’s exterior that result in fluid leaks, a bent piston, or a repositioning of the device causing excessive side loading, to name a few. The important thing to understand is that any time a hydraulic cylinder has been exposed to damage, it should be professionally inspected as quickly as possible.

Another common cause of hydraulic cylinder failure is improper maintenance. A hydraulic cylinder is a piece of precision machinery and must be treated as such. Improper installation, using the incorrect fluid or seals, and over-filling or under-filling the device are all examples of improper care that can result in low performance levels or outright failure.

Hydraulic Cylinder Repair & Maintenance That You Can Depend On

The downtime and lost efficiencies that result from poorly maintained hydraulic cylinders add up very quickly and can have a huge impact on your business, especially when they occur unexpectedly. MAC Hydraulics can minimize or eliminate these issues through regularly scheduled preventive maintenance services. And if a system does go down, we provide quick and efficient turnaround, repairing and returning equipment to service in the shortest amount of time. We are familiar with all of the most common causes of hydraulic cylinder failure.

No job is too large or too small for our skilled, highly trained, and well-seasoned team of technical experts. We offer a wide range of services, from standardized repair and maintenance to complex, customized fabrication. All of our repair or fabrication work meets or exceeds the OEM specifications of the manufacturer.

MAC Hydraulics has hands on experience in a broad array of industries. Contact us today to find out how we can support your business.

Most Common Causes of Hydraulic Systems Failure

Author: Michele Baker | Posted: February 13th, 2020

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

Common Causes of Hydraulic Failure

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

1. Air and Water Contamination

Air and water contamination are the leading causes of hydraulic failure, accounting for80 to 90% of hydraulic failures. Faulty pumps, system breaches or temperature issues often causeboth types of contamination.

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

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

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

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

2. Temperature Problems

Hydraulic systems that run too hot or too cold can cause severe problems over time. Some of these challenges include the following symptoms.

Fluid thinning:Heat can cause hydraulic fluids to thin, preventing lubrication and making the fluid more likely to leak.

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

Fluid thickening:Low temperatures increase the viscosity of hydraulic oil, making it harder for the oil to reach the pump. Putting systems under load before the oil reaches70 degrees or morecan damage the system through cavitation.

Poor heat dissipation is the usual suspect behind heat buildup, while environmental factors most often cause too-cool systems.

3. Fluid Levels and Quality

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

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

4. Human Error

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

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

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

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

Hydraulic System Troubleshooting

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

Check the motor: Ensure the motor has the correct wiring and can turn on and off.

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

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

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

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

Check valves and lines: Observe all lines for potential leaks, and tighten every connection point. Also, check the relief valve for any signs of damage.

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

How to Solve Common Hydraulic Problems

So if your system is not functioning properly, how do you solve hydraulic problems? Start your diagnosis with the symptoms you notice.

1. The System Does Not Operate, Runs Too Slowly or Quickly, or Performs Unpredictably.

Common fixes for these issues include:

Use the specified fluid amounts, types and viscosity by reviewing your manual and replacing or topping off as necessary.

Check for oil leaks or line blockages, secure fittings, and clean or replace lines if needed.

Allow for recommended system warmup time to achieve proper oil viscosity and temperature.

Check and clean or replace clogged or dirty filters.

Repair or swap out leaking suction lines.

Verify pressure compensator settings on variable displacement pumps and pressure relief valves.

Clean dirty components and fix or change out any you notice with excessive wear.

Check pump drive belts and hardware for correct alignment and tension.

Verify you are operating within your equipment's load limits and manufacturer-recommended engine operating speeds.

Adjust restrictors and relief valves accurately as indicated in your owner's manual.

2. The Oil Foams or Overheats.

Typical fixes for these issues include:

Ensure the oil is clean, full and of the recommended type.

Confirm you have the correct reservoir size and cleanliness, and clean or replace if needed.

Check the oil cooler for proper operation and fix or change it out as needed.

Confirm that engine speed is within suggested manufacturer limits.

Clean, repair or replace clogged or leaking filters and lines.

Place the control valve in neutral when idle.

3. The Control Valve Binds, Drops Load or Leaks.

There are ways to eliminate these issues, such as:

Replace worn cylinder fittings and seals.

Verify linkage and repair spool binding.

Ensure proper valve alignment and swap out worn or damaged valves.

Adjust the tension on tie bolts and bracket screws.

Replace anycomponents with visible cracks or other damage.

4. The Cylinder Leaks, Knocks or Lowers Incorrectly.

To fix these common hydraulic problems, you want to:

Replace any rods and seals with noticeable damage or wear.

Verify your load check is functioning and install a new one if needed.

Check for air in your fluids and remove it or replace leaking lines.

Swap out packing and center the actuator.

Replace leaking cylinder seals.

Verify valve type is correct for load and use manufacturer-recommended valves.

How to Prevent Hydraulic System Failure

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

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

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

Perform maintenance: It is essential to focus your operations on equipment longevity. Review your daily, monthly and annual maintenance procedures to ensure you are covering every aspect of your system according to best maintenance practices and catch symptoms early on.

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

Hydraulic System Maintenance

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

Generally speaking,you should perform maintenance at three levels.

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

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

Complete system checks:Depending on the conditions of your system, you and your team should perform complete systems checks monthly, quarterly or annually. Tasks should include running a comprehensive report on the system, cleaning devices, draining the system and replacing damaged parts.

How to Work Safely With Hydraulics

When completing system maintenance, it is essential to follow basic safety procedures. Faulty or broken parts can cause leaks, bursts and projectiles that can severely injure personnel. Some common injuries include bruises, cuts and abrasions. However, pinhole leaks can inject oil into the body, causingsepticemia that can result in the loss of a limbif not addressed immediately. To avoid these injuries, be sure to follow basic safety guidelines.

Wear safety equipment:Always wear appropriate safety gear when working close to a system, including a helmet, glasses, gloves and protective clothing and shoes.

Power down systems:Never service a running hydraulic system unless it is strictly necessary.

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

Use safety locks:Hydraulic safety locks save lives. Always use these when transporting or lifting equipment for service.

Use caution around running systems:Always keep an eye out on pressure taps, couplings and hoses when they are under pressure. If something does not look right, power down the system before checking it. Loose or faulty parts can easily become deadly projectiles.

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

Troubleshooting Charts for Eight Categories of Hydraulic Problems (2024)