When there is a need for rebuilding a cylinder and pump instead of building a new one.
It is important to regularly inspect and replace worn-out piston oil seals to ensure the proper functioning of the engine. This can help to prevent costly repairs and extend the life of the engine.

Figure 6: Oil seals for cars
First disconnect the battery earth terminal , to avoid the risk of a short circuit while the fuel pipes are disconnected.
Take extra care with a light alloy block or head. It is vital to avoid scratching the machined surface.
Orient your seal the same way as the initial install.The sealing lip should face the lubricant that requires sealing.The second lip on a double lip oil seal is intended as a dust lip. The seal must be installed at a 90°, or perpendicularly, to both the shaft and housing bore. This is an issue in cases where the housing does not have a counterbore or shoulder the seal can seat up against.
To increase the pressure around the shaft and maintain the seal’s integrity, certain lip seals have an extra spring looped into the flexible rubber part.
Nitrile
As earlier said, oil seals perform some functions that ensure the functionality of mechanical equipment and extend their lifespan. And how they do this is by retaining lubricants at all cost and not making them escape no matter how high the pressure of the machine is.
CONVENTIONAL OIL SEALS
As type A with dust lip
When it comes to choosing the right oil seal for a particular application, there are several factors to consider. One of the key aspects is the material used in the construction of the seal. Different materials offer varying levels of resistance to heat, chemicals, and wear, so it is essential to select a seal that can withstand the specific conditions it will be exposed to.
A more comprehensive study of aeration by Dinzburg8 showed that even a minimal level of aeration of an aggressive European SF oil led to protection of a VDF/HFP/TFE compound, but to severe deterioration of an HNBR compound. He notes that aeration increases the severity of aging in oil for silicone and acrylic elastomers, while decreasing the severity for FKM elastomers.
One option is to buy oil seals from specialised gasket and sealing material companies like Polymer Trade Manufacturing Ltd, which is known for its expertise in dealing with gaskets and o rings. These companies not only offer an extensive range of oil seals but also provide expert advice to help customers select the right sealing materials for their specific requirements.
