TG4 TC FB Rotary Shaft Oil Seal NBR Lip Seal ID 30-130mm OD 50-170mm Thick 12mm

Measure three dimensions on your existing seal or housing: the shaft diameter (= Inner Diameter), the bore diameter in the housing (= Outer Diameter), and the bore depth (= axial height). For this product line, the axial height is fixed at 12mm. Select the variant whose ID matches your shaft and whose OD matches your housing bore. If your shaft is worn, measure the housing bore and shaft separately rather than relying on the old seal's markings.

"TC" (also written "FB" in some regional standards) designates a double-lip seal: one primary lip that retains lubricant and one secondary lip that excludes dust and moisture. This is the most common configuration for rotating shaft applications in gearboxes, motors, and pumps. Single-lip seals ("SC") lack the secondary dust lip and are used where contamination ingress is not a concern.

NBR (nitrile) is compatible with petroleum-based mineral oils, greases, diesel fuel, and most hydraulic fluids. It performs well in the temperature range of approximately −40°C to +120°C. NBR is not recommended for use with synthetic esters, phosphate-ester hydraulic fluids, ketones, or strong acids. If your application uses these fluids, consider a Viton (FKM) seal instead.

Clean the housing bore and lightly lubricate the outer diameter of the seal with clean oil or grease before pressing in. Use a flat driver or seal installation tool that contacts the outer metal shell evenly — never strike the rubber lip directly. Press the seal in squarely until it is flush with or just below the housing face. Lightly coat the shaft contact area with clean lubricant before sliding the shaft through to avoid cutting the lip on any keyways or splines.

Common causes include: incorrect size (lip stretched or compressed beyond design range), excessive shaft runout or surface roughness (the shaft contact surface should be 0.2–0.8 µm Ra), operating temperature above the NBR limit, incompatible fluid chemically attacking the rubber, and improper installation that cuts or rolls the lip. Ensuring the shaft surface is smooth and the seal is correctly sized eliminates most premature failures.

All sizes in this listing are specified in millimeters (metric). If your shaft is measured in inches, convert to mm (1 inch = 25.4mm) and select the closest matching ID. A small difference of 0.1–0.3mm between the seal ID and shaft diameter is normal and within the lip's designed interference range. For larger mismatches, contact us to confirm suitability before ordering.

All seals in this range have a fixed axial height of 12mm. Measure the depth of your housing bore from the face to the bottom (or to any internal shoulder). The bore depth should be at least 12mm to allow the seal to seat fully. If your bore is shallower, the seal will protrude and may not seal correctly. If deeper, the seal can still function as long as the shaft engagement length is maintained.