3 Reasons Why My Hydraulic Cylinder Won’t Retract
When hydraulic cylinders don’t retract, all operations come to a halt. The situation is frustrating from a maintenance standpoint and from the downtime involved in troubleshooting the issue. Understanding common problems with retracting hydraulic cylinders can help save time and even prevent the problems altogether.
What Makes Single-Acting and Double-Acting Hydraulic Cylinders Retract?
Knowing how single-acting and double-acting cylinders operate is the first step in diagnosing problems.
Single-acting hydraulic cylinders have an internal spring and use pump pressure to extend the rod. Retracting a single-acting hydraulic cylinder involves using either the spring or the weight of the load being carried. You usually see single-acting cylinders in applications requiring single-direction lifting.
Double-acting cylinders do not have an internal spring and rely on hydraulic pump power to extend and retract the rod. These cylinders are more common and used in applications where you need to lift and push loads while maintaining precise control over movement. Keep in mind that it is normal for double-acting hydraulic cylinders to retract at a slower pace than they extend. This is due to differences in pressure created for retracting and extending functions.
With a basic understanding of how single-acting and double-acting cylinders work, we can go into possible reasons why your cylinders are not retracting.
Reasons Why Your Hydraulic Cylinder Won’t Retract
Several things can prevent a hydraulic cylinder from retracting properly. Knowing what to look for and how to avoid future problems can save time diagnosing issues and help you demolish downtime.
1. Worn or Damaged Piston Seals
Seals naturally wear over time but failing to replace them causes fluid leaks. Having insufficient hydraulic fluid in your system causes cylinders to become hydraulically locked and unable to fully retract or extend. Worn seals can also cause misalignment issues between the seal and cylinder rod, which may cause trouble when retracting hydraulic cylinders.
Preventing these issues is easy. Check your seals for damage regularly and always make sure you use replacement seals that are the correct size and choose the right material for your system’s operating temperature and pressure.
2. Bent or Dented Cylinder Rod or Barrel
Cylinder rods and barrels can become dented from impact by heavy objects or machinery. Denting can occur if you try to lift a heavier load than what your cylinder is rated to handle. Any deformation of the rod and barrel prevents the cylinder from stroking correctly, which can prevent cylinders from fully retracting.
Replacing rods and barrels at the first sign of damage is critical not only for fixing retracting issues but preventing safety issues and/or permanently damaging your equipment.
3. Hydraulic Cylinders Retracting Under Load
Sometimes hydraulic cylinders retract when they shouldn’t—an issue known as hydraulic cylinder drift. This problem is caused by internal fluid leaks and is characterized by hydraulic cylinders slowly retracting while under load. While not as serious in light-duty applications, a retracting hydraulic cylinder under heavy loads can cause major equipment damage and endanger the lives of anyone nearby. Check your hydraulic fluid levels regularly and inspect your cylinders for evidence of leaking fluid.
Performing regular inspections and using the correct hydraulic cylinder for your industry and application is the best way to prevent issues with retracting hydraulic cylinders.
Hydraulic Cylinder, Inc. carries American-made, performance-built hydraulic cylinders for mobile and industrial equipment. Our product line includes welded rod, telescopic rod, and NFPA tie-rod cylinders in various sizes to meet your requirements. Shop our inventory online or give us a call to discuss our stock and custom hydraulic cylinder solutions.