wildcat air leak

I took valve out, with magnifying glass saw something on oring, nothing on cone. sprayed with balistol , includeing seat . put it back together and did soap bubbles test on muzzle. it appeared to be fixed. Shot 3-4 times and it started back leaking, tried the 210 down to 150 bar dry fireing but didnt work. still leaking. 
ill take valve out, clean again. if that doesnt work, any suggestions besides order valve?
it couldnt be reg could it? i think valve would have to leak for air to get into barrel?
thanks

it leaked down to zero over night