How to Assess Hydraulic Cylinder Internal Leakage?

Internal leakage in hydraulic cylinders refers to the seepage of fluid past the piston head seal in double-acting cylinders, occurring within the cylinder itself. So, how can you determine if a hydraulic cylinder is experiencing internal leakage? Let’s explore some methods.

Common Assessment Techniques:

1. On-site personnel typically employ sensory methods such as visual observation, listening for unusual sounds, detecting odors, and tactile examination. If the cylinder exhibits immobility, delayed movement, temperature fluctuations in the oil, or noticeable vibrations and noises, these signs may indicate internal leakage.

2. Another common method involves extending the cylinder to eliminate any load and prevent retraction, then shutting down the system and disconnecting the rod-side oil pipe. By pressurizing the cylinder and observing for oil flow from the disconnected port, one can determine if internal leakage is present.

Assessment of Oil Discharge and Unloading:

To detect internal leakage in lifting cylinders, the main return pipe from the upper chamber is disconnected and connected to an empty basin. With the piston raised to its highest point, the hydraulic oil in the upper chamber is drained, and the multi-way reversing valve is cycled. If hydraulic oil fills the upper chamber despite the absence of pressure oil supply, internal leakage is confirmed.

Detection of Minor Internal Leakage:

Using a gear flowmeter, internal leakage can be easily identified. When the hydraulic system is unstable, theoretical flow in the pipeline should be zero. By checking for flow at both ends of the cylinder, any residual flow indicates internal leakage.

Hydraulic Control System for Molds:

Minor leakage is inevitable, but when the cylinder operates safely and steadily, a flow of approximately 5 ml/min is considered normal. If the flow exceeds 10 ml/min, leakage is likely occurring.

Detection and Display Systems:

Real-time monitoring of pipeline flow via industrial computers, coupled with internal leakage alarms, enables timely identification of cylinder leakage.

Preventing Hydraulic Cylinder Leakage: Strategies for Production, Manufacturing, and Field Operations

Hydraulic cylinders are known for their reliability in heavy machinery, but flaws in design or inadequate maintenance can lead to leakage, necessitating repairs or replacements.

Preventing internal leakage in hydraulic cylinders involves attention to five key stages in their lifecycle:

1. Design

2. Manufacturing

3. Testing

4. Assembly

5. Maintenance

To ensure quality during design, manufacturing, and testing, understanding your vendor’s quality assurance processes is crucial. For assembly and maintenance, implementing straightforward procedures is essential for maintaining Car Lift Repair Orlando cylinder functionality over time. In this article, we delve into specific methods for preventing internal leakage in hydraulic cylinders.

Design, Manufacturing Preparation, and Welding for Leak Prevention

Effective manufacturing practices involve continual improvement. For instance, at Columbus Hydraulics, the team has been refining designs and testing alterations to prevent leaks and enhance long-term performance. Detailed documentation and adherence to ISO standards enable precise tracking of product performance and the integration of successful design adjustments.

During welding, preparing hydraulic Car Lift Repair Orlando cylinder raw materials is critical for leak prevention. Chamfering the steel before welding facilitates a snug fit for the end cap, eliminating welding leaks and resulting in a more durable product.

Precision Seals

Precision seals are paramount in Car Lift Repair Orlando hydraulic cylinders. Design and preparation of tubes for airtight seals, along with post-processing techniques such as roller burnishing, ensure optimal seal integrity. Tube distortion after welding is rectified through roller burnishing, returning tubes to a perfectly round shape and maintaining an optimal surface finish to prevent leakage.


Testing is a crucial step in leak prevention. While oil testing is common, air testing offers advantages in efficiency and cost-effectiveness for identifying seal leaks. At Car Lift Repair Orlando, emphasis is placed on design and manufacturing quality, reducing the occurrence of hydraulic cylinder leakage during testing. Additionally, destructive weld testing and microscopic inspection further ensure batch perfection.

Careful Assembly to Preserve Hydraulic Seals

During assembly, attention must be paid to rod protection and fittings to prevent leakage. Protecting the chrome on the rod prevents rust, which can corrode seals over time. Similarly, ensuring proper fitting between the hose and cylinder prevents misdiagnosed leaks.

Cylinder Care in the Field

Car Lift Repair Orlando Hydraulic cylinders typically require minimal maintenance, except for equipment in sporadic use, such as off-season farming equipment. Regular operation lubricates the shaft, preventing abrasion and rust.


With proper manufacturing, testing, assembly, and maintenance, hydraulic cylinder leakage can be minimized. Investing in high-quality cylinders and implementing simple assembly and maintenance measures ensure equipment longevity and reliability.

Causes of Hydraulic Cylinder Leakage

In the realm of hydraulics, understanding the reasons behind hydraulic cylinder leakages is crucial for maintaining heavy equipment. While leaks are prevalent in the industry, many of them are avoidable. This guide highlights the primary causes of hydraulic cylinder leakage in heavy machinery and offers strategies to mitigate and prevent fluid leaks.

1. Wear and Tear

The wear and tear of components are frequent culprits of hydraulic system failures in heavy machinery. Instances such as worn pistons or barrel damage can compromise the integrity of Car Lift Repair Orlando hydraulic cylinders, leading to fluid leakages. To prevent such leakages, implementing regular maintenance checks is imperative. Establishing a maintenance schedule can streamline this process, ensuring timely inspections. Additionally, utilizing high-quality seals and components can significantly reduce downtime and repair costs associated with leak fixes.

2. Corrosion

Corrosion, triggered by contaminants like damaged pump particles and debris, poses another risk for hydraulic cylinder leakage. Regular usage of cylinders helps in forming a protective oil film on the surface, guarding against corrosion. Maintaining clean hydraulic oil is essential to prevent the accumulation of contaminants and inhibit oxidization. Regular oil sampling aids in detecting early contamination for prompt intervention.

3. Over Tightening

Over-tightening hydraulic cylinders is a preventable cause of leaks, posing both safety hazards and equipment damage risks. Excessive tightening can lead to Car Lift Repair Orlando cylinder cracks and dislodgement of snap rings, resulting in fluid leakage. Adhering to recommended torque specifications specified in product documentation ensures optimal equipment performance, longevity, and worker safety.

4. Extreme Temperatures

Extreme temperatures significantly impact hydraulic systems, potentially causing seal damage and fluid breakdown. High temperatures alter seal shapes, reducing effectiveness and leading to leaks. Conversely, cold temperatures render seals brittle, increasing susceptibility to cracking. Monitoring hydraulic oil temperature and ensuring proper cleaning of hydraulic oil coolers are vital steps in temperature management.