Benjamin marauder fill valve?

Many outlets for o rings around. harbor freight sells a kit with many sizes for under $10.

​Mine wasn't releasing either, so when I depressurized the hose, it lost a couple hundred PSI in the Marauder tank. Crosman advised to put some silicone oil on the tip of the fill valve each time I filled it and see if it would fix the problem. Did it for about three fills and the valve started working like it should.

​If you try that, make sure it's silicone oil, as normal oil will combust at the pressures a PCP works at