in my opinion you dont need to clamp the hoses, well i didnt at least. when the car is running, remove the relay for the fuel pump and the car will shut itself off. then there will be no fuel pressure left. when you pull the hoses off the filter you will get a little gas coming out, but it will stop, its just whatever was in the line and filter. replace filter, reconnect lines, replace relay and attempt to start car. it might take a little bit of starting it for it to actually start.