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Pneumatic Cylinders - Repair and Maintenance Guide
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Pneumatic Cylinders - Repair and Maintenance Guide

02 /01 /2022

8 min read

As you’ve probably experienced, there are quite a few things that can go wrong with a pneumatic cylinder. Knowing the signs to look out for, what they can be pointing to, and finally, how to perform proper pneumatic system maintenance, are the best ways to keep your cylinders in working order.

However, even with this knowledge, sometimes air cylinder repair is still necessary. Check out this easy guide on pneumatic cylinder repair to learn about the signs and causes of cylinder problems and the fundamentals of their maintenance and repair.

General Signs That Your Air Cylinder Needs Repair

There are a number of problems that can occur in a pneumatic system so we’ve listed some common signs to look out for that indicate your cylinder will need repairing.

  1. Actuating too slowly or failure to actuate at all. If nothing is moving, it’s a pretty clear indication that there’s something wrong. It's essential to monitor the actuating pressure to avoid a full breakdown of the system.
  2. A higher than normal pressure is required to actuate. If the control line is too small or the metering choke valve isn’t working, it will usually result in low pilot control pressure. 
  3. Hissing Noises
  4. Intermittent start-up. If cylinders are being overworked and overloaded, it will cause stress and higher friction of the seals. Actuators can fall apart and rod ends can bend or even break.
  5. Load pulsing. Cylinders generally run smoothly and almost silently. If that’s not the case, something is probably in need of a repair. 
  6. Visual corrosion or premature wear

Typical Causes of Pneumatic Cylinder Failure

Below are some of the most common causes of pneumatic cylinder failure:

Side Loading

If your pneumatic cylinder is failing, the most likely culprit is side loading. When pressure is applied laterally to the axis it can cause a number of problems that will ultimately result in failure including uneven or accelerated piston rod and bearing wear, seal failure, and cylinder tube scoring, among others. 

Sideloading usually occurs because the pneumatic cylinder has been installed incorrectly into the system in which it operates. Once sideloading does happen, repairs should be made quickly to ensure more damage does not occur.

Insufficient Lubrication

If you want to avoid any problems with your pneumatic cylinder, be sure to maintain proper lubrication at all times. The seals within the cylinder require thorough and constant lubrication or else they will dry out and fail. 

Contamination

Another factor that could lead to pneumatic cylinder failure is contamination. Contaminants can restrict free movement within the cylinder by blocking the operating parts. This will not only reduce the overall functionality of the cylinder but also potentially lead to total system failure.

Contaminants like particulate matter, oil, water, and others, are often easily introduced into the pneumatic cylinder, either through the operating environment or the pneumatic air supply and always with catastrophic results. 

Synchronization Issues

Any system with more than one pneumatic cylinder requires perfect synchronization of each component in order to work effectively. In order to maintain the synchronization of a complex system like this, there are a number of practices and methods in place that require careful monitoring and management. 

In the event that the pneumatic cylinders fall out of synchronization, the machine will stop functioning properly and most likely the entire system will fail. If this does occur, immediate pneumatic cylinder repairs should be made. 

Exceeding Operational Limits

Cylinder failure is inevitable when you’re operating it outside of the intended, optimal performance range. Exceeding these limits means the cylinder is exposed to excessive loads that stress the internal components of the cylinder. This leads to poor performance and almost always a premature failure. Preventative checks and maintenance can help you operate within the correct parameters and avoid this issue.

General Pneumatic Cylinder Repair Points

Knowing the basics on how to repair a pneumatic cylinder will save your team downtime and cut costs. Below are some points regarding pneumatic cylinder maintenance and repair to keep in mind:

  • Be sure to always turn off the power supply and release any leftover air before repairs and maintenance begin. Pneumatic systems have compressed air which can be very dangerous and this danger is increased when the system is still hooked up to power. 
  • Always check the cylinder, tube, and rod seal for rust or damage, as these are the areas most prone to wear and tear. If there is a lot of rust or damage, you might need to replace the entire cylinder and its mounting parts. 
  • Check to make sure there is no dust left on the outer air cylinder surface or on the mounting bracket.
  • Do not forget to lubricate! Always check every necessary component for proper lubrication and use grease packs if there is an insufficient amount. These components require proper lubrication to function at full capacity:
  1. Piston outer surface
  2. Piston rod surface
  3. Piston seal groove
  4. Piston seal inner and outer surface
  5. Rod seal
  6. Rod seal groove on the rod cover
  7. Tube gaskets
  8. Tube inner surface 
  • Don’t be stingy with seals. Over time, seals can crack, leak air, or have some other damage that will require replacement. Here are a few quick but detailed steps on replacing seals safely and effectively:
  1. Hold the tube cover in place using a vice. Then remove the rod cover using a monkey wrench or a spanner. 
  2. Start the cylinder disassembly. As you carefully remove each component, wipe the excess grease off with a clean cloth before placing the parts on another large, clean cloth.
  3. Replace the old or damaged seals with new ones, being sure to install them properly and according to the specifications in the pneumatic cylinder maintenance manual. 
  4. Reassemble the pneumatic cylinder and make sure to install the tube cover slightly tighter than it was previously.
  5. After completing these steps, apply a little operating pressure to the cylinder. Then do your usual functionality and leakage tests and if the cylinder passes, it can be reinstalled into the system.

Pneumatic Cylinder Preventive Maintenance Fundamentals

There’s never a guarantee that your pneumatic cylinder won’t fail— they can’t last forever. However, there are a few simple steps you can take to avoid failure. When done consistently and properly, these steps can save you downtime and money:

  1. Installation: It might seem obvious, but installation is one of the most important parts of caring for your pneumatic cylinder. For example, if the wrong tools are used for installation it can directly affect the functionality and longevity of the system. Installing the cylinder properly will ensure it lasts much longer. 
  2. Torque: In order for tie rods to be correctly installed, it is essential that fasteners are properly torqued. 
  3. Filters: Changing filters regularly and according to manufacturer specifications will help protect your cylinder from damaging contaminants. 
  4. Fittings: Check to make sure that the fittings aren’t rusted or wearing, as many contaminants are introduced into the pneumatic cylinder from contaminated fittings. 

Conclusion

With time, as pneumatic cylinders become more advanced and efficient, they also become more complex— and so do the problems that can occur. It’s difficult to always know how to maintain pneumatic systems, not to mention repair them, to keep them at their highest operational efficiency level. 

This guide will help you identify problems and teach you to do the essential, basic pneumatic cylinder maintenance required to keep your system working. But sometimes, repairs are best left to the professionals. At Cylinders, Inc., we offer an extensive range of repair services for your pneumatic cylinders. We’ll get to the root of the problem, complete the repairs and replace the necessary parts, and then test your cylinder to make sure it will work at maximum efficiency and productivity. 

Get in touch today and have you cylinders taken care of by our experts!

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