DDSAM14017012TC Double Lip Rotary Shaft Oil Seal, 140 x 170 x 12 mm, Nitrile with Garter Spring and Dust Lip

Product Description

What this part is

A TC-type radial shaft seal in the 140 x 170 x 12 mm metric size: 140 mm shaft diameter, 170 mm housing bore, 12 mm axial width. It keeps oil or grease inside a rotating housing and keeps dirt and water out.

Decoding “TC” — three features in two letters

TC is the metric seal trade designation for a seal that combines three things. A rubber-covered metal case: a steel stiffening ring fully encased in elastomer, so the outside diameter grips the housing bore by rubber compression rather than metal interference. That means it seals a bore that is scored, slightly oversize or made of aluminium far better than a bare metal-OD seal, and it will not spin in the bore. A garter-spring-loaded primary lip: a coil spring behind the sealing lip maintains contact force on the shaft as the elastomer relaxes and wears, which is what gives the seal a service life rather than a service moment. And a secondary dust lip — the “double lip” — an unsprung auxiliary lip pointing away from the oil that scrapes dirt, dust and splash off the shaft before it can reach the primary lip.

Why the dust lip is the reason to buy this one:
Most radial shaft seals fail from the outside in. Abrasive contamination gets under the primary lip, laps a groove into the shaft and the seal then leaks no matter how good the elastomer is. The auxiliary lip is a cheap insurance policy against exactly that. It is the right choice on any shaft exposed to dust, chaff, washdown, road spray, grinding swarf or cement, and it is why the equivalent SKF design is specified so heavily in agriculture, aggregate and construction equipment. On a clean indoor gearbox a single-lip seal is adequate; anywhere outdoors or dirty, specify the double lip.

Interchange guidance

This is a standard metric envelope, so it interchanges dimensionally with any 140 x 170 x 12 mm double-lip radial shaft seal. The closest named equivalent is SKF / CR Seals 140X170X12 HMSA10 RG (SKF US stock number 563693) — HMSA10 being SKF’s rubber-OD design with an auxiliary lip, RG being their nitrile compound. National, Chicago Rawhide and the Asian TC ranges all offer the same size. In standards terms it is the DIN 3760 Form AS and ISO 6194 profile. If you are cross-referencing an old parts book, note that Chicago Rawhide became CR Seals and CR Seals is now SKF — the CR numbers are still live and still searchable.

Material limits — read this before ordering

Nitrile (NBR) is the general-purpose oil seal elastomer and it is right for petroleum oils, most greases, water and mild chemicals. The comparable SKF nitrile compound is rated roughly -40 to 210 °F (-40 to 99 °C) and the equivalent SKF HMSA10 seal is rated to about 0.03 MPa maximum pressure — a lip seal is not a pressure seal, and a blocked breather is a far more common cause of “seal failure” than a bad seal. Nitrile is not suitable for brake fluid, ammonia, ketones, or phosphate ester fluids; those want a different compound. DDS does not publish its own temperature or pressure figures for this part, so the ratings above are quoted from the equivalent SKF nitrile design rather than invented.

Fitting notes

Install with the primary lip facing the lubricant and the dust lip outboard, toward the contamination. Getting this backwards is the single most common installation error and it turns a double-lip seal into a pump. Lubricate the lip and the shaft before assembly, never run a lip seal dry on start-up. Press the seal in square using a driver that bears on the outer face of the case, not on the lip; do not hammer directly on the seal and do not push on the spring side. Check the shaft where the lip will run: a worn groove from the old seal means you either move the seal axially, fit a wear sleeve, or the new seal will leak straight away. Chamfer or tape over keyways and splines the lip has to pass.

What you receive

Loose individual seals, each one sealed in its own poly bag — confirmed from the product photographs. This is not a boxed multi-pack lot; the price shown is per seal and multiples ship as separate bagged pieces. The bag labels read “SEALING RING AM14017012” and “AM14017012 RING SEALING” with stores numbers LH10RW304 and BR050506, unit of measure EA. Also written 140x170x12, 140X170X12, 140*170*12, TC140x170x12, TC 140-170-12, A-140-170-12.