Try some no detergent oil first 20 weight is what I use.see if this helps.Some new 392 or 397 have loose fitting valves .I dont know if the bore is too big or the oring groove is cut too deep on the valve.this is how I fix a loose valve on one I got. Take teflon tape and put a few wraps in the oring groove put new orings on and trim the excess off. Try a test fit see go on with a little resistance. How do you tell when you have a too loose valve?when you go to pump the valve out the valve sides out really easy.it should come out with some resistance.btw if you have a rifle with the stamped serial numbers you may no be able to telll if is loose because of the stamping has distorted the tube and fee l ike the valve is stuck in there.