TG4 Rotary Shaft Oil Seal

The TG4 belongs to the same family as the TC shaft seal: a metal case fully covered in rubber, so that the seal is retained by and seals statically against the housing bore, with the main lip held on the shaft by a garter spring. Trade suppliers describe the profile as carrying more sealing lips than the TC, but none publishes a lip count, and the lip arrangement cannot be read from the item photographed, so no lip count is stated here.

The seal photographed here is moulded TG4 40 65 12, following the same convention as the TC: profile letters, then shaft diameter, housing bore and width in millimetres. It is worth noting that 40 x 65 is not one of the nominal sizes in Table 1 of ISO 6194-1:2007, which lists 40 x 55 and 40 x 62 at that shaft diameter. TG4 seals are therefore supplied in manufacturers' own dimension series as well as in ISO nominal sizes, and a replacement must be matched to the housing that is actually there.

Suppliers describe the TG4 as the more pressure-tolerant of the two profiles, but none publishes a figure. No working pressure is stated here for that reason. As a general limit, ISO 6194-1 puts elastomeric lip seals of this kind at 0 to 30 kPa above atmospheric and refers anything higher back to the manufacturer, and that is the only sourced figure available.

Order by shaft diameter, housing bore and width in millimetres together with the profile letters and the elastomer. Where the duty is genuinely pressurised, a lip seal is the wrong component and a pressure-rated seal should be specified instead.