If you have an older Balzers Pfeiffer Duo 1.5 mechanical pump that needs to be rebuilt and want to do it yourself, here is a link to a detailed procedure:

http://www.rtftechnologies.org/general/pfeiffer-duo15a.html

pfeiffer-duo-mechanical-pump

For parts or rebuilding of Pfeiffer Duo 1.5 mechanical and turbo pumps, here are some companies that we have used with success:

http://www.ajvs.com/pfeiffer-uno-duo-1-5a-rotary-vane-pump-minor-repair-rebuild-kit-80010-12557

http://www.pchemlabs.com/services.asp