Check at Home Depot, Lowe's, or a plumbing supply store in your town. What you need is a brass fitting about 3 to 4" long with male threads on one end and female threads on the other. I think the threads are 1/8" pipe thread, but you can check that by comparing the threads on the sending unit. It would probably be a good idea to take it with you when you're looking for the right kind of fitting.
