Oil Seal Cross-Reference
Every oil seal — any brand, any catalog — comes down to the same four facts: size, type, material and lip style. Decode those, and any part number can be matched.
Reading the size on the seal
Most seals carry their size stamped or moulded on the face, always in the same order: inner diameter × outer diameter × width, in millimetres. Separators vary — dashes, dots, an “x” or just spaces — but the order never changes.
Type TC · fits a 25 mm shaft · presses into a 47 mm bore · 7 mm wide · nitrile rubber
| Marking on the seal | Means |
|---|---|
| 30-52-10 | 30 mm shaft · 52 mm bore · 10 mm wide |
| 25.47.7 | 25 mm shaft · 47 mm bore · 7 mm wide (dots as separators) |
| 35x62x8 | 35 mm shaft · 62 mm bore · 8 mm wide |
| 1.375 × 2.250 × 0.375 | Inch sizes — convert (× 25.4) to 35 × 57 × 9.5 mm, or ask us for the metric equivalent |
What the letters mean
The letters before the size describe the seal’s construction. Different brands use their own house codes, but these industry-standard ones cover most of what you will find:
| Code | Construction | Typical use |
|---|---|---|
| TC | Rubber-covered, double lip, garter spring | The standard rotary shaft seal — gearboxes, motors, pumps |
| SC | Rubber-covered, single lip, garter spring | Same duty as TC where no dust lip is needed |
| TG | Rubber-covered, double lip, reinforced | Interchangeable with TC in most modern applications |
| VC / VG | Rubber-covered, single lip, no spring | Grease retention, low-speed shafts |
| X-type | Four-lobed radial seal ring | Reciprocating and slow rotary rods — resists spiral twist |
| Split | Two-piece housing-style seal | Large shafts — installs without dismantling the machine |
Material codes
The rubber compound often appears after the size. Matching the material matters as much as matching the size — see the material guide for the full comparison.
| Code | Compound | Also marked as |
|---|---|---|
| NBR | Nitrile — the general-purpose default | N, Buna-N, Nitrile |
| FKM | Fluorocarbon — heat and fuels | FPM, Viton®, V |
| EPDM | Ethylene-propylene — water and steam | E, EPM |
| PTFE | Polytetrafluoroethylene — chemicals, dry running | T, Teflon® |
| VMQ | Silicone — extreme temperatures, food machinery | MVQ, S, Silicone |
| PU | Polyurethane — high-pressure hydraulics | U, AU, EU |
Have a part number from another brand?
Brand catalogues each use their own numbering, and there is no single public database that covers them all — so we do the cross-referencing by hand. Send us the part number (or a photo of the old seal and its markings) and we reply with the matching size, type and compound from our stock, usually within one working day.
Common questions
The marking has worn off completely. Now what?
Measure the shaft and the bore — those two numbers plus the width narrow it to a handful of standard sizes. Our measuring guide walks through it, and a photo of the seal remnants helps us confirm the type.
Can I replace a TC with a TG, or an NBR seal with FKM?
TC and TG are interchangeable in most modern equipment. Upgrading NBR to FKM is safe and buys heat resistance — just never downgrade FKM to NBR on a hot application, and keep EPDM away from oil.
My part number is from a machine maker, not a seal brand.
Send it anyway. Equipment part numbers often map to a standard seal once the machine model is known — and if not, shaft and bore measurements settle it.
Cross-referencing by hand, because databases miss things
Automated cross-reference tools match exact part-number strings — and fail the moment a brand renumbers a line, a marking wears faint, or the seal came from a machine maker rather than a seal catalog. Matching by size, type and compound always works, because those three facts define the seal itself. Send us whatever you have — a full part number, half a marking, a photo — and we will match it to a standard metric seal from our stock, with live pricing and one-piece ordering. Seals ship within 48 hours of ordering.