I have been having a bit of trouble with air in the fuel and have found something quite strange.

I have replaced the leak of pipes , lift pump, checked injectors, sedimenter and so forth.

I decided to have a look at the injection pump and once opened there was diesel on the dry side, top of the diaphragm.

The diaphragm has no holes but it looks like diesel was getting through the screw.

Could this cause intermittent stalling and air in the system?

TIA