Oil Seals Hardening

An oddity of oil seals is their need for lubrication because they utilise a tiny film of oil between shaft and seal to prevent the seal burring and tearing. Age hardening can be less of a problem than the damage caused to a seal that has dried out. We used to use it (along with ‘suspension wind up’) as an excuse to bounce 6 wheeler Stalwarts over rough ground. Idleness, as with hydraulics, was the enemy of good functioning.

 

I would say it completely down to the seal material they use various combinations of both material and ways of providing tension to the knife edge of the seal for example i have seen 60 year old seals that are fine yet others that have been fitted to a damaged shaft that you couldn't see with the naked eye fail in a few hours, a lot of crankcase seals simply fail because of pressurization for the wrong side, some of my Trident seals are 40 years old but are still fine.