9 Signs Your Pneumatic Cylinders Need Replacing

Post By: Tom Rowse On: 31-05-2024 Read Time: 5 minutes - Guides - Pneumatics

Air cylinders aren’t perfect. At some point you’re bound to experience problems. These could range from performance issues to component damage, causing unwanted downtime and even total equipment failure. Rather than troubleshooting problems after the event, it’s better to be proactive and watch out for signs that your pneumatic cylinders may need repairing or replacing. A programme of preventive maintenance can reveal such telltale signs in time to keep your air cylinders performing optimally. 

Does My Air Cylinder Need Repairing?

All air cylinders need repairing throughout their lifespan, but regular pneumatic system maintenance will help keep them working better for longer. We’ll explain how to spot the most common signs that your air cylinder may have problems. These signs indicate the likely causes and how best to deal with the repairs.

Sluggish Or No Actuation

If your cylinder is moving too slowly, or not moving at all, it's a clear sign that something’s wrong. Failure to actuate or sluggishness probably means that there’s insufficient air pressure to run the system. Check the actuating pressure and find out why it’s inadequate, otherwise it might lead to a complete system breakdown.‍

Low Or Unstable Air Pressure

Insufficient compressed air supply may indicate that your compressor isn’t large enough to handle all your equipment. You may suffer spikes in demand if your cylinders are sharing a circuit with other tools or machines. It’s also possible that the air filter from your compressor is blocked and needs cleaning.

Actuation Requires Excessive Air Pressure

If the level of air pressure needed to actuate your cylinder is higher than normal, it could indicate that pressure in the pilot control is too low. This could be because the control line isn’t big enough or a failure of the metering choke valve.

Intermittent Start-Up

This may be a sign that your air cylinders are overloaded or overworked. Seals will suffer higher friction and stress, while rod ends may bend or even break. This will cause the whole actuator to fall apart. Erratic start-up may also be due to pressure spikes if you’re using devices for absorbing energy or speed control.‍

Inconsistent Stroke

This can be a knock-on effect of cylinders moving at variable or slow speeds, either through inadequate airflow or because your cylinder is incorrectly sized for the stroke. It may also be that your tubing and valves are undersized and are restricting the airflow, so you need to check that they’re all according to spec.    

Erratic Cylinder Speed

Cylinders can move too quickly or too slowly if you have no flow controls, or aren’t using them properly. Make sure that flow controls are correctly located, making it impossible for operators to change the flow rates and interfere with cylinder speed control.

Hissing Sounds 

If you hear your air cylinder hissing, it’s a clear sign of a leak. This can be caused by damaged or worn-out components such as the piston or rod seals. You’ll experience pressure loss and a noticeable decline in cylinder performance.‍ Check all components and replace any worn or damaged parts.

Cylinder Banging Or Pulsing

Your cylinder should run smoothly with very little noise. If you hear banging when you power up the system, it’s possible that the cylinder was left in a retracted position when the air was shut off. The next time you power up, there’ll be a sudden rapid inrush of air. Not only will you hear a loud bang but the operation will start up too abruptly, which is potentially dangerous. You can avoid this by using soft-start valves. Loud actuation may also occur if you have no stroke-end cushioning or flow controls.

Visible Corrosion Or Wear

If you can physically see damage on your pneumatic cylinder, it probably means that it’s working in a harsh environment. You may find pitting, erosion or rust if it’s exposed to chemicals, high temperatures or humidity. This type of damage will compromise the structural integrity of your cylinder, which will eventually fail.

9 Signs Pneumatic Cylinders Need Replacing

If Your Pneumatic Cylinder Fails

If, in spite of preventive maintenance and troubleshooting, your cylinder does fail, it’s probably for one of the following reasons:

Contamination

Contamination is one of the most common factors leading to pneumatic cylinder failure. Contaminants like moisture, oil and particulates can block the operating parts of the cylinder and restrict free movement. They can get in through the air supply or just the ambient environment, reducing the cylinder’s overall functionality.

Side Loading

Another common culprit in cylinder failure is side loading. This often happens if the cylinder is incorrectly installed, so that there’s lateral pressure on the axis. Side loading can create many problems and ultimately cause failure, so you should fix the problem immediately. The effects you may notice include uneven or accelerated wear on the bearings or piston rod, cylinder tube scoring or seal failure. 

Insufficient Lubrication

You should make sure your pneumatic cylinder is properly lubricated at all times, to prevent the interior seals from drying out and failing. 

Exceeding Operational Parameters

The operating parameters of your pneumatic cylinder are specified by the OEM. If you exceed these intended limits, you’ll expose the cylinder to excessive loads, putting unnecessary stress on its internal components. Performance will be poor and premature failure is highly likely. Preventative maintenance and regular checks can help you maintain parameters and achieve the optimal performance range. 

Preventive Maintenance Is Key

Your pneumatic cylinder won’t last forever, but you can help prolong its life through regular preventive maintenance. The first steps to optimising its lifespan include correct and careful installation, using the appropriate tools and accurately torquing tie rod fasteners. Set the pressure and flow controls according to the manufacturer’s specifications, to optimise the cylinder’s efficiency. 

You should change your filters regularly to protect your cylinder from contaminants and make sure that no rust or other particulates are introduced via worn or damaged fittings. Run a regular programme of checking seals, tubes and piping for leaks and wear and tear, and replace worn components before they have a chance to break down and require complete replacement.