Common Causes of Hydraulic Cylinder Failure
In a hydraulic system, there are many potential issues that can result in hydraulic cylinder failure. These issues may arise from typical wear to the cylinders, or they may occur due to improper operation or configuration.
You may notice some signs that emerge shortly before the cylinder fails. Common symptoms of hydraulic cylinder failure include:
- Unusual or new sounds during operation
- Loss of power
- Slow or inconsistent power application
- Overheating
- Visual sediment in hydraulic fluid
Those are the signs, but here are the most common causes of hydraulic cylinder failure:
1) A Worn or Damaged Seal
The hydraulic cylinders seals are responsible for preventing leaks and contamination, as well as lubricating the piston barrel. However, they represent weak points when the piston is actuating. There are several reasons why a seal may fail, including fluid contamination, extreme operating temperatures, excessive pressure, damage to the piston rod, or just plain wear.
To do their job, seals are designed to flex and fill gaps. If temperatures climb too high or fall too low, though, the seals’ elasticity may be compromised. Degradation via thermal damage may also occur.
There are several cylinder seals to account for, including piston seals, rod seals, buffer seals and wiper seals.
If a piston seal fails, internal leaks will emerge and worsen until the piston can no longer provide power. You’ll likely notice the cylinder gradually drop in performance over time until the system completely fails.
If a rod or buffer seal fails, it will most often result in external leaks and, again, a drop in force application.
Wiper seals are positioned at the rod end of the cylinder and are responsible for preventing contamination from entering the barrel during the return stroke. If this seal fails, contaminants will rapidly enter the system and threaten the cylinder.
2) Hydraulic Fluid Contamination
Fluid contamination is the number one cause of hydraulic cylinder failures. As solid particles circulate through your hydraulic equipment, they will clog ports and valves, abrade internal surfaces, eat away at the rod’s finish, and degrade seals. In short, contaminated hydraulic fluid can cause problems throughout the system.
Early detection is important. If solid contaminants are present, you’ll likely notice sediment in the fluid when sampling it. If water has found its way into the system, the fluid will appear milky. In both cases, the fluid may foam in the reservoir during operation. Overheating is another sign that contamination may be present, as the heat exchanger or filters may be clogged with particles.
3) Improper System Operation or Configuration
Many cylinder failures come down to human error, or at least inattention. For example, every hydraulic pump and jack system is rated for an ideal range of operating pressures. If the pump isn’t set within this range, the cylinder may not load quickly enough, or at all. Verify that your personnel are maintaining operating pressures in line with manufacturer recommendations.
Further, it’s critical for personnel to monitor internal pressures during operation. Ensure there are fluid-filled gauges placed along hydraulic lines, so if pressure issues do emerge, it will be clear where they are appearing.
Errors (or carelessness) during loading can also cause severe damage to the cylinder and reduce its ability to deliver power. For example, side loading is a common, yet avoidable, problem. Cylinder rods are designed to extend and retract in linear fashion only. If force is applied perpendicular to the rod during loading, it will bend the rod and cause excessive wear on one side of the rod barrel as the rod rubs against it. Side loading can permanently warp the rod and accelerate wear.
Damage due to side loading requires extensive repairs. It can also set up the conditions for a catastrophic failure that puts workers at risk, as the cylinder may suddenly fail.
4) Corrosion on the Rod's Steel Components
Harsh environments take their toll on steel cylinder rods. Exposure to salt or acidic conditions will cause steel parts to corrode and rust with time. If this corrosion is introduced into the system during operation, it can score or pit the rod as it strokes. Corrosion can also damage seals and interfere with smooth stroking, resulting in cylinder tightness.
If corrosion is present, you’ll likely see it before any other signs are present, so visual inspections are essential. To treat it, apply rust inhibitor occasionally. In aggressive environments like those along the Gulf Coast, the recommendation is to invest in corrosion-resistant, nickel-plated cylinder rods. They are more expensive, but rated for hundreds of hours of operation in corrosive environments.
And when your cylinders are not in use, store them with the rod fully retracted. This will prevent exposure to moisture and weathering, reducing the risk of corrosion.
5) Lack of Cylinder Maintenance
Every piece of hydraulic equipment eventually wears out, but consistent, on-time maintenance will extend its life as far as possible. Further, you’ll avoid costly repairs by catching and preventing damage before it occurs.
If your crew isn’t adhering to a basic preventative maintenance schedule, it’s time to implement one. Many contractors also implement an equipment tracking system to monitor each cylinder’s performance and service history. This will help identify which cylinders are up for a round of maintenance, and if the cylinder has shown any signs of wear or damage in the past.
Most preventative maintenance routines are simple enough for a skilled operator to handle, though time may be a concern. Further, some problems can only be diagnosed with a full system breakdown and inspection.
If your crew is limited in time or technical expertise, an experienced hydraulic equipment technician can fill in the gaps.
An Expert Technician Can Identify the Cause of Hydraulic Cylinder Failure and Repair the Equipment
Hydraulic cylinders are heavy duty pieces of equipment rated for work in stressful conditions. As sturdy as they are, though, every cylinder eventually needs a checkup and the occasional tune-up. If your company doesn’t have the time or specialized technical skills to repair hydraulic cylinders, work with a hydraulic equipment maintenance team that can support your organization in maintaining its hydraulic equipment resources.