Sealing integrity is non-negotiable in hydraulic, pneumatic, aerospace, and fluid power systems. A single failed seal can compromise an entire assembly, shut down production, or trigger costly MRO repairs.
Since 1982, Pneu-Draulics Inc. has delivered critical sealing solutions for OEMs, MRO operations, and rubber and gasket houses across aerospace, military, fluid power, and manufacturing industries.
As a Parker Hannifin Seal Group distributor and ISO 9001:2015 certified company, we stock components that conform exactly to material, dimensional, and customer specifications. Learn more about our O-rings and gaskets, hydraulic cylinder sealing systems, piston and rod seal kits, and custom capabilities below.
O-Rings & Gaskets
Our O-rings meet MIL-I-45208A, MIL-P-4861B, and other Mil-Spec standards, making them a proven fit for aerospace fuel system seals and defense programs that require full material traceability. We supply DFARS-compliant seals across multiple compounds, including AMS7257, AMS-P-5315, MIL-G-21569, and general-purpose nitrile (N0674), in individually packaged or high-volume economy packs. For compound selection guidance, refer to our Aerospace Compound Reference Chart.
Nitrile Back-Up Rings
Nitrile back-up rings install alongside primary O-rings to resist extrusion under pressure spikes. They are a standard component in hydraulic cylinder sealing systems where pressure fluctuation or side-loading degrades the primary seal over time. We carry standard and metric configurations to support domestic OEM programs and international repair applications.
U-Cups
U-cups are single-acting seals used in rod and piston positions depending on orientation. Our hydraulic U-cup applications span light-duty pneumatic cylinders through heavy-duty hydraulic actuators, with nitrile and polyurethane options available in inch and metric sizes.
Before specifying a compound, consult our Fluid Compatibility Chart to confirm compatibility with your operating medium. Procurement teams sourcing hydraulic U-cup applications at volume will find both standard assembly runs and MRO replacement programs available through our catalog.
Piston Seals
Piston seals stop hydraulic fluid from bypassing the piston face inside the cylinder bore. We carry wide-base two-piece designs, composite profiles, and loaded lip configurations across a range of bore sizes. These seals form the foundation of our hydraulic cylinder sealing systems. Paired with back-up rings, rod seals, and wipers from our catalog, they give procurement teams a complete rebuild source in one place. See the Piston Seal Installation Guide for fitment details.
Wipers
Wipers scrape grit, metal particles, and moisture off the rod before it re-enters the cylinder. A degraded wiper accelerates wear across the entire hydraulic cylinder sealing system. We stock D-style metric wipers and inch-series profiles, including single-lip and double-lip designs for wash-down and outdoor environments. Common failure patterns are covered in our Seal Failure Causes guide.
Rod Seals
Rod seals control fluid leakage along the reciprocating rod as it exits the cylinder. We carry metric heavy-duty designs, step-cut profiles, and loaded lip configurations for applications that cycle across wide temperature and pressure ranges. These are a standard component in piston and rod seal kits for OEM assembly and field replacement work. For defense and government programs, we stock DFARS-compliant seals with the full documentation needed to satisfy material source requirements. Visit our fluid power solutions page for additional context on pressurized sealing systems.
Wear Rings
Wear rings center the piston and rod inside the bore and absorb lateral loads that would otherwise transfer to the sealing elements. We supply filled PTFE and reinforced composite wear rings in metric and inch sizes. Correct wear ring selection directly extends the service life of surrounding seals in any hydraulic cylinder sealing system.
Oil Seals
Oil seals retain lubricants and block contaminants at rotating and oscillating shaft interfaces. We carry single-lip and double-lip designs in nitrile, Viton, and silicone. For OEMs specifying custom seals for manufacturing equipment, we match shaft speed, operating temperature, and fluid compatibility to the right lip profile and spring load.
Vee Packings
Vee packings stack in adjustable sets that compensate for wear over time, well suited for hydraulic presses, pump housings, and valve stems where replacement clearances are tight. We supply sets in leather, nitrile, PTFE, and fabric-reinforced rubber. See our Glossary of Terms for profile definitions.
Maintenance Kits
Our maintenance kits bring together everything needed for a complete cylinder rebuild in one organized package. Each kit is configured by cylinder make and model to cut procurement time and eliminate the risk of mismatched parts.
Kits typically include:
- Piston seals
- Rod seals
- Back-up rings
- Wipers
- Wear rings
These piston and rod seal kits ship from two warehouse locations to keep lead times short for MRO operations on fixed maintenance schedules. They represent one of the most practical critical sealing solutions for OEMs managing high equipment uptime requirements.
Custom Gaskets and Seals
When a standard profile does not solve the problem, our sealing design team steps in. We build custom seals and gaskets to match non-standard groove geometries, uncommon material requirements, and application-specific pressure or temperature conditions. Our machining capabilities support seal diameters up to 23.5” (597 mm), with extended sizes up to 57” (1,448 mm) on request.
From aerospace fuel system seals requiring DFARS-compliant documentation to custom seals for manufacturing lines with tight dimensional tolerances, we handle the full specification process from first drawing to final inspection.
Request a Quote for Our Reliable Sealing Products
Pneu-Draulics has been delivering critical sealing solutions for OEMs, MRO facilities, and rubber and gasket houses for more than 40 years. Whether the need is a standard aerospace fuel system seal, a hydraulic U-cup application, or a fully engineered custom seal for a manufacturing run, we have the inventory and expertise to fill the order correctly.
Request a quote, and our team will match you with the right product for your application. Already know what you need? Our Quick Order tool lets you place your order directly. To browse everything we carry, explore our full catalog.