I have a 61 Crown that has a loud "HISSING" only when I press the brakes. I think something in the vacuum booster is leaking. Does anyone know of a good company that repairs power brake units? How long does it take? Is the vacuum unit the same for a 61 Crown, 62 Chrysler 300, and 62 Chrysler Newport? Cost? Gary Frey Email: gfreynpo@xxxxxxxxxxxxxx