so on my 78 there is a black box in my passenger side fender be hind the batter that has one hose that goes down to another black box that’s attached to the frame on the passenger side. That black box looks like it distributes vacuum. The line from the upper to lower box is basically gone. The line is a ribbed foil on the outside and almost a rubbed cardboard on the inside. My questions are; what is this system?, can I plug the broken line off and be good? Or what is this type of line and where to buy? Thanks in advanced.