The Sealing Members
Lip hardening can be caused by excessive operating temperatures, inadequate lubrications, or if the media being sealed is incompatible with the lip material.
Operating temperatures of sealed media or lubricant may exceed the recommended limits for the type of sealing member material. Make sure the seal is the correct size for the applications. if the seal is too tight on the shaft, this may cause overheating. Check that the seal was installed with and maintained adequate lubrication for the type of seal you are using.
Shaft finish may be too rough at point of lip contact. Seal may not have been properly or adequately lubricated prior to installation. Make sure the seal is the correct size. If the seal is too tight on the shaft, this may cause overheating and rapid wear. Shaft run-out or shaft whip may exceed the recommended limits. Make sure that the seal seats close to the bearing and check for excessive looseness in the bearing or splines.
Check misalignment of shaft to bore. Shaft misalignment causes rapid wear at one point on the sealing lip.
Make sure the seal is the correct size for the application. Check for excessive wear at point of lip contact. The shaft may be too soft, be sure to check the minimum shaft hardness specifications for your application. Check to make sure you used the proper installation tool. Your installation tool must not have an O.D. of more than 1/32" greater than the shaft or the sealing lip may be overstretched.
This can be caused by careless storage, handling, or the use of improper assembly / installation tools. This can also be caused by failing to properly clean and prepare shaft prior to installation and/or failing to protect the sealing member when installing over splines or keyways etc.
Oil Seal Metal Parts
The seal O.D. may be too large for the housing bore. The housing bore may be excessively out-of-round. If you find that the bore diameter and the out-of-round limits are correct, look for evidence of careless handling or the use of improper installation tools.
This may be caused by careless handling or use of improper installation tools or methods. Excessive spreading of the primary sealing lip during the installation process can damage the spring.
This can be caused by the use of improper installation tools. Check the out-of-round limits of the housing bore and make sure the O.D. of the seal is not too large for the bore. Either of these conditions can cause the seal to become distorted. Seal distortion may not be apparent, but may be enough to loosen the inner components of the seal and cause it to leak.
This can be because of the use of improper installation tools or methods. Check to make sure the seal O.D. is not too large for the bore. Also be sure to check for burrs, scale, or chips that may prevent the seal from seating properly.
Excessive Shaft Wear
Check to be sure the seal is the proper size for the shaft. Too tight of a fit will cause excessive wear on both the lip and the contact point on the shaft. Check to be sure the seal was properly and adequately lubricated prior to installation. Check to be sure that the seal stays lubricated while in use. Check for the presence of abrasive dirt or other debris. Make sure shaft was cleaned properly prior to the installation of the seal. In applications where the seal has the possibility of getting dirt or other large debris on or near the sealing lip, a seal with a dust lip should be used.
Carefully inspect and clean the shaft prior to installation. If the shaft cannot be refinished, a shaft repair sleeve may be needed.
The seal may be cocked in the housing. Check the O.D. surface of the seal for evidence of damage from installation, careless handling or improper storage prior to use. Check interior of housing for excessive roughness, foreign matter, scratches or burrs. Check housing to be sure it is not out-of-round. If the eccentricity is only slight, .001" or so, special cement on the O.D. can be used to offset this problem.