Pep Boys or another auto supply store. Around $30 for a decent hand powered pump. On a w123 where everything is vacuum, they are worth their weight in gold!

Note: Pump must have a vacuum gauge (in. Hg. ) with it to troubleshoot, although I have never seen one sold without a vacuum gauge. After you draw the air out of a line or accessory, watch the gauge and it should keep that pressure for several minutes without changing much (10%). If not, you have a vacuum leak in that part. Be systematic, and try to test just one thing at a time by removing or stopping other lines and connections. May be more difficult, but really saves time in the long run and makes it easier.

Best of Luck and have fun!
Adam