Air-dryer leaking

Well got the new after market Air dryer I noticed that it's about 1 1/2" shorter then my old one I guess no big deal. On my old check valve it would move back and forth when I shook it,this new one doesn't do that, but when I stick a little screw driver in it does move back and forth maybe the little spring on my old was more warn idk. Thanks

 

Well installed the new air-dryer works like it should,still leaks down while truck is idiling takes a while though,probably did that before just never noticed because it kept popping off every 25 seconds,forgot to bring my spray bottle to check for leaks. Thanks guys.