A standard oil seal consists of an outer circular metal disk with an inner flexible rubber which is affixed to the metal during vulcanization. The bonded seal has no loose parts to allow leakage of oil or ingress of any contaminants. This kind of seal is more accurate, and can easily be fitted into a smaller space. An example is shown in Figure 2.9.
Rotary Wheel Of Auto Parts
Sealing Element


The spark plug is essentially a device that generates an electric spark to ignite the compressed air-fuel mixture inside the engine cylinder. This ignition process creates a small explosion, which pushes the piston down and ultimately drives the vehicle forward. Without spark plugs, the engine would not be able to start or run efficiently.
With a helper holding the engine steady, remove the wedge supports, lower the engine and reconnect the mountings loosely.
One common reason leaking occurs in engines is that debris is caught in the fork seal, holding it open and allowing oil to sneak by. So, how do you fix this? This is where the little circular devices come in—oil seals.
Assembling the oil seals is only possible with the right assembly tools. Due to the high risk of damage during assembly, it is important that you have tools with which you can work carefully. A bearing fitting tool set is ideal.
U-Shaped Silicone Gasket: Applications and Advantages

Figure 1: Types of sealing devices

different types of spark plugs.
A patent for an oil seal was filed by Nelson Thomas Edward on August 12, 1937, and published a year later. There were two purposes described. The device was to provide an oil seal between a fixed housing and a rotating part. The seal is described as
ERIKS type M (type B according to the DIN standard) has a single metal casing and rubber sealing lip. Since the casing is made of metal, it must be fitted in a well-finished, undamaged groove. Large volumes of oil seals with metal casings are often cheaper, which is why they are often used as original equipment in machines. However, if an oil seal has to be replaced, types with a rubber exterior (type R or RST) are easier to fit. Type MST is similar to M and commonly used. The difference is the dust lip in the MST oil seal that prevents dust and dirt reaching the sealing lip, and extends its service life in dusty environments.
Common materials used in oil seals include nitrile rubber, fluorine rubber, silicone rubber, acrylic rubber, polyurethane, polytetrafluoroethylene, etc. When selecting the material of the oil seal, the compatibility of the material with the working medium, the adaptability to the working temperature range and the ability of the lip to follow the rotating shaft at high speed must be considered. When the oil seal is working, the temperature of its lip is higher than the working medium temperature by 20~50°C. Attention should be paid when selecting the oil seal material. The working range of the oil seal is related to the material used for the oil seal: the material is nitrile rubber (-40~120°C), Aggreko rubber (ACM) -30~180°C, fluorine rubber (FPM) -25~300°C.
What are oil seals?
Valve stem seal