Tuning Leaking Gamo Urban

I recently pumped my Urban up to near max (possibly a bit over, not on purpose but possibly). It leaked out overnight that night. I was able to order enough to seals to seal the whole gun twice from Gamo/Daisy in Arkansas. Anyway, the seals came in yesterday and I replaced all the seals in what I call the "top end" which is the entire screw out brass portion that makes up the fill probe and gauge. Before the seal replacement it would leak off through the fill probe hole and after the seal replacement it leaks heavily out of the fill probe hole. The only part I didn't replace was the plastic valve that sits under the spring and washer that is pinned in place. I did take it apart and clean it. Any ideas on what is going on?