


Requirements of the shaft
Even more important than a correct interference fit of the Oil Seal is a perfectly smooth shaft in the region of the seal, particularly if shaft surface speed is high and the medium to be sealed is under a certain amount of excess pressure. The surface roughness of the shaft depends on the average profile depth Ra of the tool marks caused by the machining process. Oil Seals made of PTFE require, independent of the surface speed, a surface roughness of between 0,1 to 0,2 mm, because PTFE has less wear resistance than rubber seals. For normal circumstances, the shaft in the region of the seal must have a surface roughness of approximately: To summarize, the surface of the shaft in the region of the seal should not have noticeable machining marks. For pivoting shafts and other difficult or critical sealing applications, it is recommended that Oil Seals with a helical groove hydrodynamic pattern, which has a pumping effect, be used. When grinding and polishing, an axial movement of the grindstone along the shaft must be avoided in order to prevent machine lay.
NBR, also known as nitrile rubber or nitrile, is the most popular material for an oil seal because of its good resistance to many oils and greases, such as mineral grease and hydraulic oil. Depending on their composition, synthetic oils and greases, such as those based on glycol, can damage NBR rubber materials. Depending on the amount of glycol, a PTFE lip seal may be the best choice. NBR is also unable to cope with contact with acids and solvents. The rubber is suitable for oil and grease at temperatures from -35 °C to 100 °C.

Oil seal material
Intake Valve Cover Gasket: Importance in Engine Functionality
Rubber type
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.
Several variables, including maximum temperatures, required lubricants, available space, and more, may influence your choice of bearing seal. Each factor can affect the type of bearing best for your application, the amount of material required, and other factors. Although the choice of seals is crucial to the effectiveness of your bearings, you don’t have to make that choice alone. Our experts at NBC bearings can collaborate with you to identify the bearings and bearing seals that provide the best, most affordable solution for your application, environment, and finished product.


Oil seals increasingly had to meet higher requirements, which is why PTFE was developed in 1980. This variant can better withstand higher engine speeds, higher oil temperatures, longer oil intervals and modern lubricants. In addition, the oil seal contains a wider contact surface, which ensures less wear.
Wilmink Engine Parts offers a wide range of oil seals for various applications and engines. Poor-quality oil seals can cause problems. Our range offers only quality brands and our specialists will be happy to help you choose the right product for your application. Below, we highlight some of our brands with their catalogues around oil seals.
Installation of the oil seal


oil seal
The quality of the rubber or rubber fabric used to make an outer case is the same as the quality of the rubber sealing lip. Fabric reinforced rubber is, as the name suggests, rubber reinforced with a fabric.
In addition to its durability, the 25x47x7 oil seal is also known for its ability to operate effectively in a wide range of temperatures and environments
. Whether in extreme heat or cold, the seal is able to maintain its integrity and provide a consistent barrier against oil leaks. This versatility makes it a popular choice for use in a variety of industries and applications.25x47x7 oil seal
