Water dispenses even when not on brew?

If the pump is running then either the brew button is depressed, the steam knob is not closed far enough or some wires have gotten crossed or reconnected wrong. I would start with the steam knob; with the top of the case removed it should be obvious if it's closing far enough to deactivate the pump switch; if not, you'll need to adjust the stopper to correct this behavior. Leaking from around the lip of the portafilter might indicate that your brew head gasket needs to be changed; it should be clean and slightly springy when prodded. If it's hard or has a groove worn in it then it can't provide a good seal.