A kit for a Bendix (not necessarily the same as yours - yours might be Clayton Dewandre and might be a single cylinder rather than a twin cylinder - with other Atlantean owners around you should be able to identify what make) compressor (scroll down for a list of parts):-
http://www.ebay.co.uk/itm/Bendix-Air...item3f2e7b943d
If you need parts try:-
http://www.partline.co.uk/Automotive...TYPE=Air+Brake
or any commercial motor factor - once you know what you need