The skeleton oil seal is a typical representative of the oil seal. Generally speaking, the oil seal refers to the skeleton oil seal. The function of the oil seal is generally to isolate the parts that need to be lubricated in the transmission parts from the output parts, so as not to allow the leakage of lubricating oil. The skeleton is like the steel bars in the concrete member, which acts as a reinforcement and enables the oil seal to maintain its shape and tension.
If these specific tools aren’t available, it’s entirely possible to correctly seat an oil seal in its housing using a hammer. Ideally, this hammer will be plastic or rubber due to it’s more forgiving nature. Using this and a strike plate that covers the entire seal will lend you accuracy while driving it in. The downside to this method is the inability to drive the seal any further than the strike plate will allow.
Valve stem seal

Seals are classified by O.D. wall material, lip type, and whether they have a spring or not.
Major oil seals are specified in ISO 6194-1 and JIS B 2402-1.
Table 2 shows the common types of oil seals, while Table 3 shows the features of each type of oil seal.
Table 4 lists the JTEKT oil seal type codes and corresponding ISO and JIS standards.
Product Manager of Sealing & Polymer Technology
What is an oil seal and how does it work?
Constructional Aspects of an Oil Seal:
What material are oil seals made from?
-40 °C to + 90 °C


Oil seals are found in a wide range of applications, in virtually every industrial sector. It is essential to select the correct oil seal so that the application in which it is used can run efficiently, free of leaks or other issues. In this blog, we explain which factors you should pay attention to when selecting the best oil seal for your application.

All are fitted with a spring to preload the sealing lip. All these types are for non-pressurised or low-pressure applications up to 0.5 bar for diameters of a limited size. For diameter of 500 mm or more, the maximum pressure is 0.1 bar. For higher pressures, special types or PTFE lip seals can be used.