depends on how old it is, alot of cam seals I have seen are so old and brittle once they are moved they never seal like they used to. you can always try to puch it back in but I doubt it will move if everything is torqued down. everytime I do cam seals I always take the cam out and work the new cam seal carefully down the camshaft untill it is positioned back in place, but of course this is on a DSM. if you can put the new seal on by just taking the cam gear off then go for it but from what I could imagine it would be hard to push the new seal in place because it is supposed the be very snug.