2.5 NAD question

when I bought my Series IIA with a 12J 2.5 NAD, a pump was not connected to any thing on the block. (see photo, arrow towards pump)
While looking for an answer of what the pump does, I came across the attached photo. What is the purpose of this pump, can I drive while it's disconnected or do I have to reconnect it and if Yes how to.
I could not find this in the manual of the defender.

Thanks Bas

It is a caccum pump for the brake servo. A piece of pipe goes from there to the terminal on the side of the servo unit (big black round thing right in front of drivers position).

Aye it's the vacuum pump for the brakes. If you've got non servo assisted brakes it's redundant.

Thanks!

But best disable it because if you leave the big blck hose open the poor pump will knock its pan in trying to make Britain into a vacuum.#

Stuff a suitable bolt in the end of the hose and tie out of the way.

You could always fit a vacuum servo to the brakes, and make use of the thing..

CharlesY