Faulty installation is a common cause for seal failure in today’s vehicles. But the most common reason a seal fails is because it is the incorrect seal for the particular application. It is very important to check the old seal and replace it with a correct seal for the application.
When replacing an old seal in an application, you first should use the number on the old seal to identify the replacement seal. If there is no seal listed in exactly the same width, a narrower width is usually the best choice. A wider width is perfectly acceptable if space permits, however it is often limited.
If you are installing a seal in a new application, it is important to gather all measurements associated with the seal – seal bore diameter, seal outside diameter, and seal width and shaft diameter. When measuring a seal’s outside diameter, always remember to take measurements in at least three places equally spaced around the seal. Taking the average of these readings represents the seal’s diameter.
Speed, temperature and pressure also play a role in selecting the correct seal.