High pressure common rail fuel pump outlet check valve retainer

A pumping element comprising:

• a first flow chamber;
• a second flow chamber in fluid connection with the first flow chamber, the second flow chamber including a first section having a first diameter and a second section having a second diameter, the first diameter being smaller than the second diameter;
• a first insert being moveable between a first position wherein the first insert forms a seal that inhibits fluid flow between the first and second flow chambers and a second position wherein the first insert permits fluid flow between the first and second flow chambers;
• a second insert disposed within the second section;
• and
• a third insert disposed within the second section, wherein the third insert includes a shell and an insert inserted into the shell to cause expansion of the shell to retain the third insert in a fixed position within the second flow chamber;
• wherein the second insert is intermediate the first insert and the third insert, and the first insert moves from the first position to the second position in response to pressurized fluid in the first flow chamber.