Well sucking air

[jkebxjunke]

My one pump is sucking air from the well- especially after sitting awhile. I have check the check valve (no pun intended) and it looks and functions properly, the pipe past the checkvalve is galvanized pipe. I have pumped the system up and left it off for over 2 days.. the pressure in the system held. Now when you turn it on it sounds fine for about 5-8 seconds then you can hear the sound of air going through the impellers. This has been an unusually wet year this year so I dont think it should be going dry. The well was put in around 1977. I am hoping that I dont need a new well. It might be a 2" washed in well ( never seen the top of it but have an idea where it is)
I am thinking of digging it up and replacing the pipe between the well and the pump before I consider it dead and have to have a new one put in.
Any advice thoughts or suggestions?
Thanks.