I reinstalled the old fuel pump on my 216 today. Last year I had replaced it with a dual action pump in hope of improving the performance of my vacuum wipers ( no luck there). The old pump now leaks like a sieve. It worked fine when I removed it last year. The gas seems to be coming from the bottom ( the pump is mounted with the glass bowl on top). The connections are not leaking. Is it possible that sitting in the box in my shop for a year caused it to go bad?

My dad always told me, "Don't force it, get a bigger hammer".