Webley Alecto Not Holding Air

Each time I pump my Webley Alecto air escapes from the top hole on the piston. Any ideas why and how to fix?

Does it fire and you just hear it, or is it not expelling a pellet. I have two, and they both wheeze a bit during pumping, that's normal. If it doesn't shoot, send it back for warranty repair.

Air is expelled from the piston on compressing. No air is then retained.

Well that's not good! Sounds like a seal is gone. I am no repair wizard, and have not worked on my Alectos (Alecti?) other than to take the grips off, sounds like a job for an air gunsmith. How did this happen, did it just quit working, more than 3 pumps? I thought these were pretty bullet proof guns by the looks of them, now I'm worried. Have you tried oiling the piston through the hole like the manual says? Maybe the seals are just dry and the oil will plump them up and fix he leak. That works with Crosman pistols, I've done it many times with great success. Good luck in getting your pistol up and running soon.