Often, when parts such as oil seals fail prematurely, they are replaced and returned under warranty; however, in most cases, the seal itself is not the cause of the failure. In this guide, we’ll take you through why and how to avoid premature leaks and failures in the future.
If the lip is worn, this is usually due to unusually high temperatures, foreign material present, disproportionate internal pressure, or an excessively rough shaft surface due to seals not being adequately lubricated prior to installation. Likewise, if the lip hardens and cracks appear when removing the seal, you can be sure that again this is caused by abnormally high temperature, high internal pressure, or insufficient lubrication. The reason for the abnormally high wear is due to friction, as the amount of lubricant is below the specified level and therefore does not reach the sealing lip. Alternatively, dry wear conditions may result in insufficient lubrication due to the vehicle’s low oil level. Another sign is whether the lip wear band is smooth and shiny.
Or, if the lips have softened, the main reason for this is that the lips have the incorrect material required for the application. To prevent this from happening again, be sure to source the correct seal for your specific application prior to installation.
If you notice uneven wear on the seal lip, this is due to warped seal installation or excessive shaft offset. As before, it should be checked during installation, but crucial before the vehicle hits the road.
Installation errors are often a significant factor in the premature failure of automotive parts. If you can see the lip of the seal being scratched, this is obvious due to improper assembly, improper handling, incorrect shaft chamber or foreign material entering the seal. Scratches are usually due to burrs or other defects in the shaft cavity during assembly, the lip coming into contact with sharp metal parts during shipping or storage, or if gloves are used to handle seals that are contaminated with metal particles.
As previously mentioned, poor handling can be a factor in premature seal failure, marked by swelling or softening of the seal lip. The swelling is caused by the lips being soaked in solvent or gasoline prior to installation. Alternatively, if when disassembling the seal you see a partial break in the mating marks, the seal may be deformed due to a poorly designed assembly jig or a gap in the press fit due to rough handling.
However, while problems during assembly can lead to part failure, other problems can be critical factors. If the waist (curved area) of the lip breaks, it may be due to improper assembly, but it may also be triggered by excessive internal pressure. Similarly, if the lip is overturned, the lip edge is heavily worn and the wear band is concave, this is related to the wrong shaft chamber, improper assembly and too high internal pressure, which means that the oil seal area exceeds the maximum pressure originally designed for . To prevent this from happening again, determine the maximum pressure of the seal and check that it is compatible with the vehicle. However,
Likewise, if the lip is badly worn, the surface has grooves or indentations. Foreign matter can affect seals in a number of ways, whether it is due to contamination of the shaft or seal with foreign particles being used, or contamination embedded in the sealing lips. The cause can be triggered when the seal is assembled in the presence of dirt and/or dust, causing contaminants to become lodged in the sealing lip. Also, if the seal or housing is assembled with silicone, the sealant can contaminate the shaft or seal.
If, when removing the seal, the garter spring has broken off, then this may be caused by an incorrect shaft chamber or incorrect assembly, checking the installation can ensure that you and your customer are satisfied with the job done.
However, if there is no apparent failure of the oil seal, the cause is often difficult to diagnose, but before condemning a good seal prematurely, check the shaft for scratches or the wrong diameter, if the shaft is not rotating in the correct direction with the helix on the seal Mismatch, excessive shaft offset or runout, worn shaft or improperly installed seals.
Press-Fit Area Leak Diagnosis
If the oil seal is warped, it may be due to incorrect bore size, incorrect shaft housing, or incorrect assembly jig.
If there is no problem with the oil seal, as with the lip leak diagnosis, check for scratches or improperly sized holes or excessive hole surface roughness. Likewise, if the outer diameter of the seal is damaged or scratched, it is usually the cause. Be sure to check for incorrectly sized bores, incorrect shaft chambers, or incorrect assembly fixtures before installation.
All mentioned causes can be avoided if the correct steps are taken when assembling, ordering and installing parts.