Ok Sleepyheads.
While you Brits are enjoying some well earned horizontal downtime I think I have this sorted.
With true, non-scientific methodology I did two things at the same time so either could be the cure but we won’t know for sure until you get all whingy and I repeat the test in two sections. 😎
I pulled the FCD again today, took out the SS shaft and popped it into a cordless drill chuck.
Then I got one of my bored gicleurs, put some polishing paste on the face, mated it up to the shaft and turned on the drill.
I used light finger pressure and a couple of reapplications of polish and there was a visible refacing of the brass mating surface.
There was a distinct change when mounted in the mushroom.
Previously there was an obvious air leak when I sucked on the bottom of the mushroom with the FCD closed.
After lapping, the pin closed tight with no leak, in fact it took extra effort to open/break the seal while sucking.
Of course, I then muddied the waters by adding PTFE tape to the gicleur threads when assembling.
Once back in the machine she is back to behaving like a good Italian girl should.
Pressure up and down as it used to and the ability to totally shut off the flow.
Thanks for all the suggestions and hopefully this might help someone else.
Oh If anyone down under wants some of the little Viton O-rings I bought a bag of 100 brown ones for about $20.
send me your address and I’ll pass some on.
