Why can a worn shaft sealing track cause leakage after a new seal is installed?

LILY Bearing | 2026-10-28

Best answer

Inspect the whole sealing interface

A contacting seal functions against a counterface, not in isolation.

JTEKT's sealing guidance identifies the shaft-contact interface as part of the sealing function, while its shaft and housing guidance treats surface condition as a technical requirement. Replacing the seal does not restore a damaged or worn counterface. The investigation should therefore distinguish the condition of the removed seal from the condition and geometry of the surface it contacted. This does not prove that every repeat leak is caused by a shaft track. It explains why a new seal alone is insufficient evidence that the relevant interface has been restored.

Preserve the location of the old contact track

Record the seal identity, orientation, track location, visible wear or damage, and the relevant shaft drawing or seal-manufacturer requirements.

Photograph the interface before cleaning removes useful evidence. If a repair changes the seal position, shaft surface or adjacent component, identify the controlled method and the basis for accepting that change; do not treat moving the lip to a fresh-looking area as a universal repair instruction. Compare the whole interface under the applicable inspection procedure. The record then allows the reviewer to assess the original leak and the proposed correction, instead of relying only on the fact that a new sealing component was installed.