Rancilio Silvia OPV rebuild - cleaning & sealing advice

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
jv2024
Posts: 2
Joined: 2 months ago

#1: Post by jv2024 »

Hi all,

New to the forums, but a happy Rancilio Silvia user for 21 years (original pump, original boiler!).

It's all original except for a PID mod, newer/flatter shower screen and silicone grouphead gasket.

I was recently pulling a shot when the OPV failed open, dumping water from the boiler back to the tank.

I have a rebuild kit on the way from Stefano's that should arrive by this weekend - can't get here soon enough, my mocha pot is fine for camping, but I NEED my double shot in the morning :D

I have a couple of questions:

How should I clean the the OPV housing before installing the new parts? Seems pretty dark in there from old coffee residue maybe?

What is the white stuff on the old OPV parts? Some sealant they use at the factory I'm guessing. Should I use something when I reinstall the rebuild kit? Teflon tape, or something else? Or does the O-ring seal without need for anything else?

I'm attaching a photo of the OPV bits showing the white stuff I'm talking about.

JRising
Team HB
Posts: 3703
Joined: 5 years ago

#2: Post by JRising »

jv2024 wrote: How should I clean the the OPV housing before installing the new parts? Seems pretty dark in there from old coffee residue maybe?

What is the white stuff on the old OPV parts? Some sealant they use at the factory I'm guessing. Should I use something when I reinstall the rebuild kit? Teflon tape, or something else? Or does the O-ring seal without need for anything else?
You could soak all the brass in a mild citric acid (or a store-bought descaler like Urnex Dezcal) solution for as long as it takes to get things shiny. On the bits you can wire-brush, that will remove the white stuff quickly.

The white stuff is calcium, and I think the picture answers the question about needing sealant. No calcium deposited beyond the o-ring, so the o-ring seems to seal pretty well on its own.

jv2024 (original poster)
Posts: 2
Joined: 2 months ago

#3: Post by jv2024 (original poster) »

I appreciate your help!

I'll give it a try with just the o-ring and a wire brush and dezcal worked well to clean up the parts.

zapageck
Posts: 1
Joined: 2 months ago

#4: Post by zapageck »

Soak and clean with a soft brass brush i.e. used for spark plugs