Overflow valve for fuel injection pumps, NOT for W124, W201, W210, etc.
At the back of the fuel injection pump you can find the overflow valve. The original overflow valve opens at ca. 0.5-1.5 bar and ensures a constant pump pressure. Age and maturity can wear out the overflow valve so that the pump pressure falls due to a too early opening valve. This results in insufficient fuel supply.
In late W124 diesels overflow valves with with plastic pins were mounted which wears out more quickly.
As a replacement, we offer an overflow valve as an all-steel model (spring loaded steel ball, s. detail image) with an increased opening pressure of 2 bar. This ensures an improvement of the internal pump pressure and thus an optimal filling of the pump elements -> maximized performance.
When replacing, you have to dismount the banjo bolt at the back of the ESP and mount the new overflow valve with two flat washer al-m14.