My NOS seals were really hard. I soaked them in neatsfoot oil for a few days and then pushed them onto an arbor the same diameter as the journals they run on just to stretch them to size. They were still pretty hard after that, so I threw them back into the neatsfoot oil and forgot about them for about a month. When I took them out there was only a little improvement, but, even though it was a tight fit, they slipped onto their journals just fine when I assembled everything and are pliable enough to do their jobs. A friend said be boiled his in linseed oil and they softened right up. You might try that too. Good luck with them.
Jon
