TC Skeleton Oil Seals ID 33mm / 34mm / 35mm — NBR 70 Dual Lip Rotary Shaft Seal Ring

Measure the shaft (inner diameter), the bore (outer diameter), and the housing depth (thickness) with calipers. For example, a 35mm shaft in a 52mm bore with 8mm depth needs a 35×52×8mm seal. Always confirm all three dimensions before ordering. If the old seal is available, measure it directly — the ID, OD, and thickness are typically stamped or molded on the face.

NBR (Nitrile Butadiene Rubber) with a Shore A hardness of 70 is the standard compound for oil seals. It generally resists petroleum-based oils, greases, and fuels well, and is suitable for operating temperatures typically ranging from -40°F to +250°F (-40°C to +120°C). It is not recommended for use with brake fluid, phosphate-ester hydraulic fluids, or highly aromatic fuels.

A dual lip (TC type) seal has a primary sealing lip that retains lubricant and a secondary dust lip that blocks contaminants from entering the housing. Single lip seals only retain lubricant. For most rotating shaft applications exposed to dirt or moisture — such as agricultural equipment, outdoor power tools, or vehicle axles — a dual lip TC seal is generally the better choice.

NBR 70 TC seals are generally suitable for environments with water splash and moderate moisture exposure. The secondary dust lip helps exclude water and debris. However, for continuous submersion or highly aggressive chemical environments, a Viton (FKM) seal is typically recommended instead. If you are unsure, contact us with your application details.

TC skeleton oil seals in this size range typically handle shaft surface speeds up to approximately 4–6 m/s under normal lubricated conditions — roughly 800–1,200 RPM for a 35mm shaft. Actual limits depend on the specific application, lubrication quality, and surface finish of the shaft. Contact us to confirm suitability for high-speed applications.

NBR 70 is generally compatible with mineral-based oils, ATF (automatic transmission fluid), and many hydraulic fluids. Compatibility with fully synthetic oils (PAO or ester-based) varies — in most cases NBR performs adequately for typical service intervals, but for long-term exposure to aggressive synthetics, confirm compatibility with your fluid's technical data sheet.

Lightly lubricate the seal lip with clean oil before installation. Press the seal in squarely using a seal driver or a flat block — never hammer directly on the seal face. Ensure the shaft has a chamfered or smooth lead-in edge to avoid cutting the lip during assembly. The seal should be flush with or slightly below the housing face once seated.