See:

http://www.peachparts.com/shopfor...light=smog+pump

http://www.peachparts.com/shopfor...?threadid=16303

http://www.mbca.org/discussion/thre...rch=smog%20pump

http://www.peachparts.com/shopforum/showthread.php?threadid=26274&highlight=smog+pump

Rebuilt pumps are available and not hard to install, but you should also check the related valves which also may need to be replaced.