Metric NBR Oil Shaft Seal Dust Grease Seal TC Double Lip w Spring ID 15-20mm

Measure three dimensions on the existing seal or the shaft/housing: the inner diameter (ID) of the seal, which must match the shaft diameter; the outer diameter (OD), which must match the housing bore; and the width (thickness), which must fit the available depth in the housing. All three dimensions are listed in the variant name in the format ID × OD × Width (e.g., 17x30x7mm). If the old seal is still in place, measure it directly with calipers before ordering.

TC is a standard designation for a double-lip oil seal with a garter spring. The primary inner lip retains lubricant (oil or grease) and is held against the shaft by the spring. The secondary outer lip acts as a dust and dirt excluder. This two-lip configuration makes TC seals the standard choice when both fluid retention and contamination exclusion are needed on a rotating shaft.

NBR (nitrile butadiene rubber) is compatible with petroleum-based oils, greases, hydraulic fluids, and moderate fuel exposure. It performs reliably across a typical temperature range of −40 °C to +120 °C. NBR is not recommended for use with synthetic esters, phosphate-ester hydraulic fluids, or ketone-based solvents. If your application involves these fluids, a Viton (FKM) seal would be more appropriate.

Oil seals are generally not reusable. The sealing lip deforms slightly to conform to the shaft surface during use, and removal typically damages the lip geometry. Reinstalling a used seal — even one that appears undamaged — significantly increases the risk of early leakage. Always fit a new seal when reassembling a component.

Apply a thin film of clean grease or oil to the sealing lip and the shaft surface before installation. Press the seal squarely into the housing bore using a seal driver or a flat piece of material that contacts the outer steel case evenly — never strike the rubber lip directly. Drive the seal in until it is flush with or just below the housing face. Avoid cocking the seal during installation, as this can permanently distort the lip.

For reliable sealing, the shaft surface in the contact zone should have a finish of approximately Ra 0.2–0.8 µm (8–32 µin). A surface that is too rough will accelerate lip wear; a surface that is too smooth may not retain the thin oil film needed to lubricate the lip. Spiral machining marks on the shaft can pump fluid past the seal and should be avoided. If the shaft shows a wear groove from the old seal, the new seal should be positioned slightly offset from the groove, or a shaft repair sleeve should be used.

Metric shaft seals are manufactured in a large number of standardized size combinations because different equipment manufacturers specify different shaft and bore dimensions. The variant selector on this page lists all 63 available size combinations in the format ID × OD × Width. Use calipers to measure your existing seal or the shaft/housing, then select the matching size from the dropdown. If you are unsure, contact us to confirm before ordering.