Step Seal Selection Guide for Hydraulic Cylinder Rods

When sourcing high-performance rod seals for heavy-duty hydraulic cylinders, purchasing managers and mechanical engineers often evaluate Step seals as a premium sealing option. It is a widely used single-acting composite seal, engineered specifically for piston rod installation in hydraulic systems.

A Step seal consists of two core components that work together to deliver reliable sealing performance:

• Filled PTFE sliding ring: This main sealing element adopts a stepped profile design. It has ultra-low friction coefficient, outstanding wear resistance and chemical compatibility. It eliminates stick-slip movement during reciprocating motion, which ensures smooth operation and precise positioning of hydraulic equipment.

• Inner elastic O-ring energizer, available in NBR nitrile rubber or FKM fluoroelastomer. This elastomer component provides continuous radial preload force. It automatically compensates for minor wear of the PTFE sliding ring, and keeps the PTFE ring tightly pressed against the piston rod surface to maintain stable sealing effect.

As a single-acting seal, the Step seal can withstand high hydraulic pressure from one direction only. It is installed in the piston rod groove, commonly used together with DHS wiper seals for complete rod side sealing protection. This combination is widely applied in heavy-duty hydraulic machinery, hydraulic presses, injection molding machines and construction equipment cylinders.

There are clear material options to match different working conditions:

• NBR nitrile rubber O-ring: The standard economical option, compatible with common mineral-based hydraulic oil, suitable for regular temperature working environments.

• FKM fluoroelastomer O-ring: Premium high-temperature and chemical resistant option, used for high heat or corrosive hydraulic fluids.

Compared with common PU rod seals such as UN seals, Step seals run much smoother, generate less heat during continuous reciprocating movement, and maintain longer service life under sustained high pressure conditions. Its compact groove design also simplifies cylinder machining.

We supply Step seals in a full range of standard sizes. Custom dimensions can also be manufactured to match your unique piston rod groove specifications.

Important Note: Step seals are designed exclusively for piston rod installation. They are not suitable for piston sealing applications. For piston high-pressure sealing, you may refer to our Glyd ring piston seal.

Contact us for catalog, technical datasheets, samples and bulk order support for your hydraulic sealing projects.