This seems nonsense to me, why do you need to run sudo su?
What do you expect to obtain?

1) use su with root password to open a root shell
2) use sudo <command> to perform a command as root (if allowed in /etc/sudoers)
3) use ssh root@localhost to open a root shell (with root password)

Don't delete your root password as this exposes you to all sorts of security risks.