The Common Rail High Pressure Pipe is a formed pipe, with sealing interfaces at both ends with fastening screws or nuts.
The Pipe assembly transports fuel at high pressure between pump and rail, and rail and injectors, resisting to pressure changes, and with a total sealing to the outside world.
Delphi Diesel Aftermarket has developed the Sealed Rail Kit (YDT278) which is a simple pressure and back-leakage test, and its use requires the removal of the Pump to Rail High Pressure Pipe.
Following this operation, and any system intervention that necessitates the removal of a High Pressure Pipe, Delphi Diesel Aftermarket recommends that the pipe is changed. When the pipe is fitted, the end deforms to create a tight seal which is essential to prevent leakage at the very high pressures generated within these systems.
Upon removal, the pipe end retains this deformed shape, and if refit, it cannot be guaranteed that the seal will be tight - even the smallest groove on a re-used pipe has potential to cause a serious leak at maximum system pressure.