A seal tube assembly of a pump system is provided. The seal tube assembly includes a single seal tube having a first axial end sealably coupled to a first vane pump and a second axial end sealably coupled to a second vane pump. The single seal tube includes transverse contact surfaces at the first axial end and transverse contact surfaces at the second axial end. The single seal tube is formed to define a first seal tube cavity at the first axial end and a second seal tube cavity at the second axial end.