Well, 5/16" is 3 thousands smaller /ubbthreads/images/graemlins/tongue.gif Ha ha, really though, I could see the lines being close (enough) in OD, but they use metric fittings, correct? For the OP, just make sure to get the right fittings (summit was mentioned and sometimes it comes with end fittings, but that wouldn't do much good; just a heads up so you're not 1/2 way into it and then woops).
[edit - I suppose the original oem fittings could be salvaged; use a flare nut wrench though, if you don't want to curse!]
Still curious what is meant by cleaning the lines...Is it just the outside and minor 'stains', or rusty? If just dirty, a good degreaser would work fine, but don't get too aggressive with scrubbing. Otherwise, may be just as easy to replace, as mentioned...