The high-pressure fuel lines and connector tubes are considered single-use components in the Cummins common rail system. Reusing them can lead to dangerous fuel leaks, poor engine performance, and starting issues. — These components create a seal under extremely high pressure, often exceeding 20,000 PSI. The sealing surfaces on the connector tubes (also called fuel supply tubes) and the flares on the injector lines deform upon initial torquing to create a perfect, leak-proof seal. Once loosened, they can never be re-torqued to reliably create that same perfect seal. This kit includes a new injector line set (PN 1050150) and six new Bosch fuel supply tubes (PN F00RJ01572) to guarantee a reliable, leak-free repair and restore proper fuel delivery to the injectors.