Greg - will take another try at this one. My first post was done when I was in a hurry.
Carter produced at least 6 different versions of these glass bowl filters, each taking a different ceramic filter. These filters may vary in one dimension or another by less than an eighth of an inch. Unless you KNOW SPECIFICALLY BY PART NUMBER which filter you need, and find an N.O.S. one in the box, your chances of matching up the filter are about 1 in 25 (other companies also made their own versions, with ceramic filters). While various of the filter elements regularly show up on Ebay, the springs virtually never show up. There are about 10 variations on Ebay now. Try the search - Carter ceramic filter - and check the box to search descriptions as well as titles. But you may purchase several before you get lucky, and there is still the spring.
We restore these things, but currently out, and won't have any done at least for 1 year, so figure I can get by on here mentioning the restoration, since we have none for sale.
We acquire used units, and when we have accumulated 75 to 100, we sort them, and then restore all of a given type at the same time, sending all of the steel pieces to an electroplater, and painting the zinc alloy with epoxy paint; and replacing the original leaky cork gaskets with a modern neopreme. Doing 10 or more allows us to take the time to determine which element is used; and then when they are sold, we inform the customer of the part number of the element. This allows the customer to watch Ebay and other places to acquire additional elements.
Suggestions - depending on what you are trying to do:
A) The cheapest and best solution is a modern inline filter at your local parts house!!! The ceramic filter does filter out large grasshoppers (and small birds), and yes, if you have one with the Carter Magna-trap, it will filter out rust. But the ceramic filter was obsoleted in the 1960's because the paper filters did/do a better job plus they are cheaper, and don't break when accidentally dropped!
B) If you want the glass bowl unit with ceramic element for "looks of the period", try to find a COMPLETE unit, either at a swap meet or on Ebay, and restore it. There is a complete 1950's unit on Ebay right now for about 50 bucks, which is a decent price. If you are going for looks, the deeper bowls were used in the 1930's, 1940's, and 1950's. There are also some of the shallow bowl versions on Ebay in the 30 buck range. These were used in the very late 1950's and early 1960's before the paper filter obsoleted them.
C) Another method of acquiring a glass bowl filter with PAPER element is visit your local auto parts store. Purolater had them as late as a few years ago, I haven't checked lately. The tops are the wrong color for the 1950's look, but red paint is cheap.
Jon.
