Metric TC Oil Seal FKM Dual Lip Rotary Shaft Seal 8mm–40mm Bore

Measure three dimensions on your existing seal or housing: inner bore diameter (ID), outer diameter (OD), and lip width (thickness). All three must match your housing and shaft. Use the variant selector above — sizes are listed as ID × OD × Width in mm (e.g., 20*40*7mm means 20 mm bore, 40 mm OD, 7 mm wide).

FKM (fluoroelastomer, often known by the trade name Viton®) is a synthetic rubber with outstanding resistance to petroleum oils, synthetic lubricants, fuel vapors, and elevated temperatures — typically up to 200 °C (392 °F). It outperforms standard NBR (nitrile) seals in high-temperature or chemically aggressive environments such as turbocharged engines, hydraulic systems, and industrial gearboxes.

A TC seal has two lips: the primary lip retains lubricant inside the housing, while the secondary (dust) lip faces outward to block dirt, water, and debris from entering. A single-lip seal only retains lubricant. TC seals are preferred wherever contamination ingress is a concern, such as agricultural equipment, off-road vehicles, and outdoor machinery.

Clean the housing bore and shaft thoroughly. Apply a thin film of compatible grease to the seal lip and shaft. Press the seal squarely into the bore using a seal driver or a flat block — never strike the seal directly with a hammer. Ensure the seal sits flush or slightly below the housing face. Avoid nicking the lip on shaft keyways or splines during installation.

The FKM lip material is inherently resistant to moisture and mild chemical exposure. The carbon-steel case may surface-rust if stored in humid conditions for extended periods; apply a light oil film to the outer case if long-term storage is anticipated. In service, the seal is protected by the housing bore and the lubricant it retains.

TC oil seals are suitable for low-to-moderate pressure rotary shaft applications such as hydraulic pump input shafts and motor output shafts, where shaft-side pressure is near atmospheric. They are not designed for high-pressure dynamic sealing (e.g., piston rod seals). Verify that your application's shaft speed does not exceed the typical 6 m/s surface velocity rating for this seal type.

With 233 size combinations available — bore 8–40 mm, OD 20–75 mm, width 5–12 mm — most standard metric shaft seal dimensions are covered. If you cannot find your exact size, contact us via the store's contact page with your ID × OD × Width measurements and we will advise on the closest available option or alternative sourcing.