An easy way in WSUS 3.0 to get space back on the drive that holds the WSUS update, is to run the WSUS cleanup wizard. This wizard gets rid of unneeded updates such as expired updates and superseded updates.

 First off launch the WSUS MMC.

 Now if we go to options and launch the server cleanup wizard.

 Now you will have a selection of options on what you want to do to get some space back.

You have a number of options to choose from, see below to see what each of these options clear up.

Unused updates and update revisions
This removes older updates and update revisions that have not been approved in the last 30 days

Computers not contacting the server
This deletes all client computers that have not contacted WSUS in the last 30 days

Unneeded update files
This deletes all update files that are not needed by updates or by downstream servers.

Expired updates
This declines all updates that have been expired by Microsoft.

Superseded updates
This declines all updates that meet the below criteria.

The superseded update has not been explicitly deployed to a computer group for ninety days or more

The superseded update has been on the server for thirty days or more

The superseded update is not reported as needed by a client

The superseding update must be approved

This should get you back quite a bit of space, around 10-20gb depending on when you last ran the WSUS cleanup wizard.

Hope this Helps  

Daniel Davies