Oil Seal Metric Nbr Double Lip Style TC 25mm 26mm Gear Shift Shaft Oil Seal

Measure three dimensions on your application: the shaft diameter (inner Ø), the housing bore diameter (outer Ø), and the cavity depth. Match all three to the variant listed as Inner Ø × Outer Ø × Depth. If you are replacing an existing seal, the size is often stamped on the seal face or listed in your equipment's parts manual.

"TC" designates a double-lip seal design per DIN 3760 / ISO 6194 classification. The primary lip (facing the oil side) retains lubricant, while the secondary lip (facing outward) acts as a dust and dirt excluder. This dual-lip arrangement makes TC seals the standard choice for gearboxes, axles, and other applications exposed to external contamination.

NBR (nitrile butadiene rubber) is compatible with petroleum-based gear oils, automatic transmission fluid (ATF), hydraulic oils, and greases — the most common fluids in gearboxes and axle assemblies. It is not recommended for use with brake fluid (DOT 3/4/5), phosphate-ester hydraulic fluids, or ketone-based solvents. If your application uses these fluids, consider a FKM (Viton) seal instead.

Clean the housing bore and shaft thoroughly. Lightly lubricate the sealing lip with the same oil the seal will retain. Use a seal driver or a flat press plate to push the seal in squarely — never hammer directly on the seal face. Press until the outer face is flush with or just below the housing surface. Avoid dragging the lip over sharp keyways or splines; use a sleeve or tape to protect the lip during installation.

NBR TC oil seals typically operate reliably from –40 °C to +120 °C (–40 °F to +248 °F). Short-term excursions up to approximately +130 °C may be tolerated, but sustained high temperatures accelerate rubber hardening and lip wear. For applications with continuous temperatures above +120 °C, a FKM (Viton) or PTFE-lipped seal is recommended.

No — the inner diameter must match your shaft diameter precisely. A 25 mm bore seal is designed for a 25 mm shaft, and a 26 mm bore seal for a 26 mm shaft. Using the wrong bore size will result in either a loose fit (leakage) or an overstretched lip (accelerated wear and leakage). Always confirm your shaft diameter with a vernier caliper before ordering.

These seals are manufactured to metric TC dimensions consistent with DIN 3760 and ISO 6194 style specifications, which are the widely adopted standards for radial shaft seals in European and Asian equipment. This makes them suitable for cross-referencing against OEM part numbers from major seal manufacturers for metric TC oil seal 25mm and 26mm bore applications.