Hi to All.
I am at last the owner of a beautiful red Peppina. I rebuild her but she constantly drips through the one of the three group screws.
The screws are new Philips type but the problem persists even if i install the old copper one.
There is no leak through the group washer but only through this particular screw (the one near the main body).
Do i have to search for a wider screw or fill around the screw with plumbers masking tape?
Thanks a lot.

It's due to the large flapper washer being under tightened. I know it seems counterintuitive. I had this same issue after I rebuilt one recently. What is happening is water is getting past the large flapper and it has one place to emerge - the group. I took it back apart, tightened the large washer so it just started to cup, and once reassembled, no more drip.

Thank you grog.
However i am afraid that the big valve is there for prohibiting water going back to boiler,so i think that its normal to have water in the group head in any given time and the grouphead valve is there to prohibit the flow to the showerscreen.
I think that probably is normal to have sitting water in the grouphead until the next pull, but not normal to see water dripping through the screw seat only.
Anyway if my only problem is a further adjustment of the big valve, that' s fine.
Any suggestion is welcome.

If adjusting the flapper valve doesn't work, Teflon tape on the threads should.

The flapper washers are two way valves. So yes, they prevent water from flowing back into the boiler, but the large washer is also what is keeping water from just emptying out of the boiler. The drip is because, due to under tightening of the large washer, a tiny amount of water is continually coming out of the boiler. If you put a bowl under the group, the drip won't stop until the water in the boiler is nearly drained out. That's how you know the issue isn't just residual water sitting in the group.

Thank you my friends.Your answers are very interesting.I think that using your suggestions i will finaly solve the problem.I ll report back.

Unfortunately tightening the big washer valve didnt solve the dripping.Actually made it worst.
In any case the group was dripping more or less.
I will try the teflon tape to the screw thread.
Maybe the original screws were brass and soft for a reason.To secure perfect with their soft thread.
The new ones are steel but hard and stiff so there is a litlle free play that permits the water flow through the thread.
I m still not sure whether is normall to have standing water in the piston till the next pull or it must be empty.
Do you have dripping if you unscrew this particular screw whithout pulling?

One very important thing I forgot to ask - have you replaced the seals and washers? If you are re-using the originals and they are old and becoming brittle, no adjusting will mitigate the issue.

You can wrap the dispersion screen screws in teflon tape to get a more secure fit, but you still have to address the underlying issue of where the dripping water is coming from. Think of it this way- the purpose of those screws is not to prevent the flow of water out of the group. That's what the small flapper washer is for (as well as to allow water into the group during a pull). The screws are there to hold the group assembly together, which is the dispersion screen, PF gasket, and the smaller metal spacer discs under those parts. The dripping is a symptom of another issue. If the group drips continually, it's not just residual water sitting in the group.

I have one too and it was sucking some coffee back into to the tank/ boiler when I pulled and released the lever. It also was not pulling an adequate amount of water (due to back flow into tank and I fixed it (large flapper.)



ABOUT THE BIG FLAPPER

Do NOT Over Tighten It. Thats a problem. Loosen it then SLOWLY turn screw until flapper is flat then STOP and LEAVE IT ALONE because that big flapper is supposed to be FLAT. If it's too tight it pulls the middle in and the outside flaps up like an upside down mushroom.

If the flapper has a permanent mushroom shape which happens over time and use you probably can flip it over (the little dimples/pressure impressions that line up with the holes are due to wear and does not mean it will only work on one side) and again SLOWLY tighten until until the dome is flat THEN STOP. Over screwing is the problem because it's easy to think the screw needs to be tight all the way IT DOESN'T. If you are obsessive about a tight screw then you may want to shim to precise height.

When the flapper does take a shape it's time to change it but in my case I found flipping it over worked just fine but a new one is in order if it's really beat.

Yep. Don't overtighten to the point of cupping, but also don't undertighten due to fear of cupping it. It is a case of fine tuning. And as you note, you can shim it with foil, although probably not necessary with a properly adjusted new washer.