HP pump blocked/airlock - SOLVED (Kind of)

[MixerFistit]

Can anyone advise on the HP pump?

Had a leak in my filter housing (hairline crack) so just changed it over but only get cranking no matter how much priming I do. First I suspected the new housing but diesel passes through.

I took off the HP pipe at the pump side and primed again and got nothing.

I took off the regulator and primed I do get plenty of diesel there, reinstalled and still nothing at the HP pipe.
So there appears to be something stopping diesel getting through between the regulator and the HP outlet

Would a faulty regulator block ALL diesel? I don't even get a dribble at the HP outlet.
I know the gauze on the regulator can get blocked so I may cut the end off before ordering a new one but has anyone seen anything similar?

I've also tried towing and bumping and still nothing. I thought if I got the pistons moving a bit it might shift any air but didn't want to keep trying in case it was dry and I did damage.

[MixerFistit]

Solved by swapping the top of the filter housing with the old one.

Haven't got a clue why it should matter but as soon as I swapped and primed, diesel came out of the HP outlet. Put it all back and started first time.

Simplest solution in the end. After checking all of the pipes individually, I just can't see how the filter could be to blame. It must be routing the diesel through backwards or something but looks identical. This one may remain a mystery