root password

[Ken Russell]

linux heads--
I am having a heck of a time trying to change the root password. I log in
under my user name, su to root, issue 'passwd', it goes through the motions
as if everything were hunky-dory, but when I exit root and try to get in
again, its the old password. Is there something special about changing the
root password?
thax for your help!
-ken