Need help trouble shooting the cause my Benjamin Bulldog will not take air. it had not been used for 4-5 months and was a little low on air. Connected to my bottle and brought it back up to maximum pressure. When I bled the fill line from the tank and disconnected the Foster fitting, air was slowly leaking back out. I emptied the air reservoir and filled again, same slow leak. I then took the male Foster fitting off the bulldog hoping to find signs of trash or water but it looked normal. I put the fitting back on and tried to fill and now no air can be sent to the air reservoir. Any ideas what could be wrong ? Thanks.