I inherited an old house. Main shut off is leaking by slightly. Any ideas on how to repair this without having the city come to shut off the outside main? The valve is an old style gate valve with packing nut. I've thought about putting a newer valve further in on the line. The problem is, the plumbing is so old that I am afraid of breaking pipes. P.S.- Total replacement of all pipes is not an option which I want to take on. Too expensive.