TC FKM Rotary Shaft Oil Seal — Double Lip, 8mm–30mm Bore, Multiple Sizes

Measure three dimensions with calipers: the shaft diameter (ID), the housing bore diameter (OD), and the housing depth (Width). The variant format is ID × OD × Width in millimeters. For example, selecting 20*40*7 means a 20mm shaft, 40mm housing bore, and 7mm housing depth. When replacing an old seal, you can also read the size stamped on the seal's metal case. If your measurements are in inches, multiply by 25.4 to convert to mm.

FKM (commercially known as Viton) is a fluoroelastomer rubber that generally offers superior resistance to petroleum oils, synthetic lubricants, fuels, and high temperatures compared to standard NBR (nitrile) seals. FKM seals are typically rated for continuous service up to approximately 200°C (392°F). If your application involves high heat, aggressive chemicals, or synthetic fluids that degrade nitrile, FKM is generally the preferred choice.

TC-type rotary shaft seals are designed for low-pressure dynamic sealing — typically up to approximately 0.3 bar (4.4 psi) of differential pressure. They are not suitable for high-pressure hydraulic circuits. For pressurized systems, a different seal design with a backup ring or a hydraulic rod seal is generally required.

Yes. The TC double-lip design includes a secondary dust exclusion lip that faces outward, helping to block water, mud, and debris from reaching the primary sealing lip. FKM rubber also offers good resistance to weathering and UV exposure. These characteristics make TC FKM seals a common choice for agricultural equipment, outdoor power machinery, and light off-road applications.

All dimensions are metric (millimeters). The TC cross-section profile is standardized per ISO 6194 / DIN 3760, so these seals are generally dimensionally interchangeable with OEM seals of the same ID × OD × Width from most manufacturers worldwide. Always verify the three dimensions match your application rather than relying on brand-specific part numbers alone.

Clean the housing bore and shaft running surface. Lightly lubricate the seal lip with the fluid being sealed or a compatible clean grease. Press the seal in squarely — use a seal driver tool or a flat block that contacts the outer metal case evenly. Never strike the rubber lip directly. The metal case should sit flush with or just below the housing face. To protect the lip from sharp shaft edges or keyways during installation, use a chamfer on the shaft end or an installation sleeve.

For reliable sealing, the shaft running surface should generally have a finish of Ra 0.2–0.8 µm (8–32 µin). A surface that is too rough will accelerate lip wear; one that is too smooth can reduce the hydrodynamic film that lubricates the lip. Heavily scored or corroded shafts should be repaired with a shaft repair sleeve before installing a new seal.