I have a 1992 Town & Country. My air conditioning is leaking out of the high pressure valve. The low pressure valve is a standard R134a connector, and I am able to add refrigerant just fine. The high pressure side, however, looks like a large tire valve stem instead of the quick connect like on the low pressure side. I am also missing whatever cover it's supposed to have. Any suggestions on finding a replacement cover or whatnot? I just went to my local NAPA store, and the only quick connect valve they had was too large to fit my "tire stem".