Hi everyone!

I thought it would be useful information, because I spent some time to search the information.

Interesting finds, not necessarily surprising.
I just replaced my group head gasket (plus O ring and shower screen) for my Lelit Victoria.
Since my machine is approximately 3 years old I ordered, as per the recommendation, an 8.5mm gasket (standard one is 8mm). It seems like the previous owner did the same thing. However, the old gasket has a groove and a bevel. I’m guessing it’s because of the compression and wear.
Also, unsurprisingly as well, the portafilter only locks at 7 o’clock for the time being.

Technical details, to save you from searching the internet:
Gasket:

original part number MC930-2 and it’s made out of rubber. Old version, 8mm, is MC752-6
I ordered the silicone version from Cafelat
you should always put the gasket with the stamping/rounded edge up (towards the boiler) flat edge down, facing the portafilter

O-ring: part numbers MC752-8

Clean the grouphead well, with a brush and wipe any coffee residue.

Don’t over tighten the shower screen either (I’ve seen people complaining about leaks when doing that).