NBR TC Oil Seal 22–28mm Shaft | Nitrile Rotary Lip Seal | TG4 TC FB | Many Sizes

Measure three dimensions: (1) your shaft outer diameter — this is the seal's ID; (2) the housing bore inner diameter — this is the seal's OD; and (3) the available axial depth in the housing — this is the seal's Height. For example, a 25mm shaft in a 42mm bore with 10mm of axial space needs a 25 × 42 × 10mm seal. All three dimensions must match for a proper fit. When in doubt, measure twice and compare to the variant list above.

TC (also called TG4 or FB) designates a double-lip rotary shaft seal. The primary lip contacts the shaft to retain lubricant; the secondary lip acts as a dust and dirt excluder. This two-lip design makes TC seals the most common choice for general-purpose shaft sealing in gearboxes, motors, and pumps.

TC-type rotary shaft seals are designed for low-pressure dynamic sealing — generally up to approximately 0.3 bar (≈4 psi) of differential pressure. They are not suitable for high-pressure hydraulic circuits. For higher-pressure applications, a PTFE or VITON lip seal is typically recommended.

NBR nitrile rubber generally performs well in water, petroleum-based oils, and mild chemical exposure, making it suitable for most outdoor equipment in moderate climates. However, NBR is not recommended for prolonged exposure to ozone, UV radiation, or aromatic/halogenated fuels. For harsh outdoor or chemical environments, a VITON (FKM) seal is typically a better long-term choice.

For reliable sealing, the shaft surface should generally be hardened to 45–60 HRC and finished to a surface roughness of Ra 0.2–0.8 µm (8–32 µin). Shaft peripheral speeds are typically compatible up to around 4–6 m/s for standard NBR TC seals, though this varies by seal size and lubrication conditions. Rough or corroded shaft surfaces will accelerate lip wear.

NBR is generally compatible with mineral-based oils, gear oils, and many hydraulic fluids. Compatibility with fully synthetic PAO or ester-based oils varies — in most cases NBR performs adequately for moderate exposure, but for long-term contact with aggressive synthetics, confirming chemical compatibility with your specific fluid is recommended before installation.

Apply a thin film of clean grease or the sealed fluid to the sealing lip before installation. Use a seal driver or flat press tool that contacts only the outer metal case — never strike the rubber lip or the inner face directly. Press the seal in squarely until the outer face is flush with or just below the housing bore face. Avoid cocking the seal during installation.

NBR rubber typically operates reliably between approximately -40°F and +250°F (-40°C to +120°C). Continuous operation near the upper temperature limit may accelerate lip wear and reduce seal life. For applications regularly exceeding +250°F, a VITON (FKM) seal is generally recommended for longer service life.