I have recently bought a second hand gaggia classic (2014). I have bought a new Rancilio Silvia V1 &V2 steam want to fit, however when I’ve go to fit it,the original wand/arm is just clicked in with a plastic fitting, there is no hit holding it it. The steam works ok, but when I’ve gone to put the original wand/arm back in it doesn’t appear to be frothing the milk very well any more. Could anyone help me? Am I missing a nut? Thanks