Metric TC Oil Seal (TG4-TC-FB) – Dual-Lip Rotary Shaft Seal | ID 45–55mm

Measure three dimensions with calipers: the shaft diameter (= ID), the housing bore diameter (= OD), and the housing groove depth (= T/thickness). All three must match your application. For example, a 50mm shaft, 70mm bore, and 10mm groove depth requires a 50mm × 70mm × 10mm seal. To convert from inches, multiply by 25.4 — a 2-inch shaft ≈ 50.8mm, so a 50mm or 52mm ID seal may apply depending on housing tolerances. Always confirm with a caliper measurement.

TC (also designated TG4 or FB depending on the standard) refers to a double-lip seal: a primary lip that retains lubricant on the inboard side, and a secondary lip that excludes dust and light moisture from the outboard side. This is generally the most widely used configuration for rotating shaft applications in gearboxes, pumps, and axles worldwide.

These seals typically use a nitrile rubber (NBR) sealing lip bonded to a steel outer case. NBR is generally compatible with petroleum-based engine oils, gear oils, and greases across an operating temperature range of approximately −40°F to +250°F (−40°C to +120°C). Compatibility with synthetic fluids, ATF, or specialty lubricants should be confirmed before installation — contact us if you need clarification.

The secondary dust lip provides protection against water splash and light contamination, making these seals suitable for most outdoor equipment in typical conditions. They are not rated for full submersion or high-pressure washdown environments. For those applications, a cassette seal or labyrinth seal design is generally more appropriate.

TC-type oil seals are generally designed for low-to-moderate shaft surface speeds (typically up to 4–6 m/s) and are intended for atmospheric or near-atmospheric pressure differentials. They are not suitable for high-pressure hydraulic cylinder rod sealing. Always verify against your equipment's OEM specifications for exact limits.

Apply a thin film of clean oil or grease to the sealing lip before installation. Use a seal driver or flat press plate to push the seal in squarely — never strike the seal face directly with a hammer. Press until the outer face is flush with or just below the housing bore surface. Take care not to nick the lip on keyways, splines, or sharp shaft edges during installation.

All dimensions are in millimeters (metric). If your equipment uses inch shafts, convert by multiplying inches × 25.4. For example, a 1-3/4" shaft ≈ 44.45mm (closest ID: 45mm) and a 2" shaft ≈ 50.8mm (closest ID: 50mm or 52mm). Always verify the housing bore OD and groove depth as well, and confirm fit with a caliper before installation.

This size range is commonly found in automotive rear axles, agricultural tractor gearbox output shafts, industrial pump shaft seals, electric motor end shields, and general power transmission equipment. Always cross-reference the OEM part number or measure the existing seal before ordering to ensure a correct fit.