A seal fitting assembly comprises a first block having a first aperture, a second aperture, and a first annular sealing surface surrounding the first aperture. A second block has a third aperture and a fourth aperture. An insert has a fifth aperture, a second annular sealing surface, and a second threaded portion. A first seal structure is disposed between the first annular sealing surface and the second annular sealing surface. An adapter has a sixth aperture, a surface of the adapter defining the sixth aperture including a third threaded portion configured to engage the second threaded portion of the insert. A second seal structure is disposed between the insert and the adapter. A fastener is received in the second aperture of the first block and the fourth aperture of the second block.