This vacuum elbow, part number 022 129 637, connects the auxiliary air valve to a case breather hose on a 74-83 Type 2 Bus or Vanagon with an air-cooled engine. It fits 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982 and 1983 models.Hose Elbow for Air Filter Housing