Hydraulic O-Rings — Piston, Rod & Cylinder Sealing
FITCO manufactures hydraulic O-Rings in NBR, HNBR, FKM and PTFE for rod seals, piston seals, gland seals and cylinder applications. AS568 and metric sizes, manufactured in India, shipped worldwide.
Right compound for your fluid and pressure
Hydraulic systems operate under dynamic pressure cycles that rapidly expose any material weakness in the seal compound. The fluid chemistry, operating temperature and pressure range together determine which elastomer will last rather than swell, harden or extrude through the clearance gap.
| NBR 70/90 | Mineral and petroleum-based hydraulic fluids, general hydraulic service to 100°C |
|---|---|
| HNBR | Mineral fluids with high-pressure or dynamic service, sour-gas hydraulics, abrasive environments |
| FKM 75/90 | Synthetic hydraulic fluids, fire-resistant fluids, high-temperature hydraulics to 200°C |
| EPDM | Phosphate-ester hydraulic fluids (Skydrol-type), water-based fluids — not for mineral oil |
| PTFE Back-up | Anti-extrusion ring paired with NBR/FKM O-Ring in high-pressure gland designs |
Where each seal sits
A hydraulic cylinder uses multiple O-Rings at different positions — each with its own pressure face and wear exposure. FITCO can supply the full gland kit from one source.
FITCO's recommended hydraulic compounds
NBR 70 / NBR 90
The standard specification for mineral hydraulic fluid service. NBR 90 provides extra extrusion resistance at higher working pressures without a back-up ring in some gland designs.
NBR material details →HNBR
FITCO's recommended upgrade from NBR where abrasion, high pressure or sour-gas contamination is a concern. Better mechanical strength and tear resistance under dynamic cycling.
HNBR material details →FKM 75 / FKM 90
For synthetic hydraulic fluids, fire-resistant fluids and high-temperature service beyond NBR's capability. FKM 90 for maximum extrusion resistance at high pressure.
FKM material details →Sourcing hydraulic O-Rings from India?
Send your cylinder bore, rod diameter, working pressure and fluid — we'll confirm the compound and dash number.