TC Skeleton Oil Seal Ring Rotary Shaft Sealing NBR Double Lip Seals ID 155-200mm

Remove the old seal and measure three dimensions: the inner diameter (ID) — the bore that contacts the shaft; the outer diameter (OD) — the dimension that presses into the housing; and the thickness (width/depth). Use calipers for accuracy. Match all three values to the variant options listed above. If the old seal is damaged, measure the shaft diameter directly for the ID, and the housing bore for the OD.

A TC seal has two lips: the primary lip retains lubricant (oil or grease) inside the bearing cavity, and the secondary dust lip faces outward to block contaminants such as dirt, water, and debris from entering. A single-lip seal only retains lubricant. TC seals are preferred in environments where both oil retention and contamination exclusion are required — such as agricultural axles, outdoor equipment, and wet or dusty industrial settings.

NBR (nitrile) is compatible with most petroleum-based mineral oils, greases, and many ATF formulations. It is generally not recommended for use with phosphate-ester hydraulic fluids, ketones, or highly aromatic fuels. For synthetic ester-based fluids or aggressive chemical environments, consider FKM (Viton) seals instead. When in doubt, consult your equipment's fluid specification and cross-reference with NBR compatibility charts.

For reliable sealing, the shaft surface in the seal contact zone should have a finish of Ra 0.2–0.8 µm (approximately 8–32 µin) and a hardness of at least 45 HRC to resist lip wear. Avoid lead-in chamfers with sharp edges — a 15–20° chamfer is recommended to prevent lip damage during installation. Shaft runout should be within 0.1–0.2mm TIR depending on shaft speed.

Apply a thin film of clean grease or the retained lubricant to the seal lip and the shaft surface before installation. Use a seal driver or a flat press plate that contacts only the outer metal case — never strike the rubber lip directly. Press the seal in squarely until it is flush with or slightly below the housing face. Protect the lip from sharp keyways or threads during installation using a sleeve or tape wrap.

TC skeleton oil seals are designed specifically for dynamic rotary shaft applications where the shaft rotates inside the seal. They are not intended for purely static face-seal applications. The garter spring maintains lip contact force as the shaft rotates. Typical shaft surface speeds for NBR TC seals are up to approximately 4–8 m/s depending on lip lubrication and operating temperature — consult your equipment specifications for exact limits.

Common causes of premature seal failure include: incorrect size selection (ID/OD/thickness mismatch), excessive shaft runout or surface roughness, installation damage to the lip, fluid incompatibility, operating outside the temperature range, and dry running (no lubrication at the lip). To maximize seal life: verify all three dimensions before ordering, inspect and refinish the shaft surface if worn, lubricate the lip at installation, and ensure the housing bore is clean and free of burrs before pressing in the new seal.