If you are getting out of space on the drive where you are saving WSUS updates, you can install a new drive and then move the updates to the new location. You can use WSUSUtil.exe with MoveContent command to move the updates to new location.
wsusutil movecontent contentpath logfile -skipcopy [/?]
The new root for content files. The path must exist.
The path and file name of the log file to create.
Indicates that only the server configuration should be changed, and that the content files should not be copied.
/help or /?
Displays command-line help for movecontent command.