Can't remember where I read this but it has worked several times for me. Some of the vacuum lines are difficult to reach and replace. Here is a little trick. Disconnect the vacuum line at both ends. Take a length of 18 gauge electrical wire and thread it from one end of the vacuum line until it appears at the other end. Now, take your new vacuum line, push it over one end of the electrical wire, and use it to push the old vacuum hose off. When the new vacuum hose appears at the other end of the wire, pull the electrical wire out and connect the ends of your new vacuum hose. Saves scratched knuckles and fingers trying to fish the new hoses underneath the inlet manifold.