I was the victim of webshots killing my pictures, they are reposted here:
http://www.flickr.com/photos/advance-design_parts_co/8129373734/in/set-72157631868452754
There are differences and some pieces do interchange. Have you put in a new gasket? If so that may be part of the problem because the foam type does affect the seating and closure. Some pictures may help in assessing the problem.