Group servicing, today's La Pavoni Europiccola

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rpavlis
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Joined: 12 years ago

#1: Post by rpavlis »

I realised today that it was past time to service my 1999 Europiccola's group. At the beginning of this year I decided that perhaps three months would be adequate, so I would perform it at each change of season. I unfortunately forgot the beginning of summer. It was amazing how much tar and the like was inside after six months. I washed everything with soapy water and then rinsed it all with 190 proof alcohol. (You can get this as Everclear at a rum shop. Because of inflation it costs about the same for denatured alcohol in US hardware stores, and pure alcohol without toxic things to prevent people drinking it is obviously a better choice.)

I have always used Dow 111 silicone for internal lubrication and external. I think it a bad idea to use anything but Dow 111 or equivalent for any internal parts including the seal on the rod attached to the piston. Other greases are often toxic, and they can cause serious damage to seals. This grease had badly deteriorated on the pins for the handle. (I threw away the trashy ones on the original long ago and replaced them with brass rods capped with "acorn" nuts.) It seemed to me that it would be better to use automotive wheel bearing grease for these pins and for the roller. Most wheel bearing grease contains solid lubricants like molybdenum disulphide in addition to the petroleum based grease. These greases are incompatible with polysiloxane greases like Dow 111. Thus I carefully removed all the silicone grease from the roller and the pins and the hole in the piston rod and relubricated it with wheel bearing grease. It is quite apparent from several posts on HB that serious damage will be inflicted on a group (many brands, not just La Pavoni) when not enough attention is paid to keeping lever pivots and lever pivot rollers lubricated very well. At the next servicing I will see if the wheel bearing grease hold up better than Dow 111 for lever pin lubrication.

Since this machine is a REAL brass and copper one rather than fake with brass plating, I also polished all the bare copper and uncoated brass. It is easier to that with the group removed from the boiler.

When I had it all together I enjoyed a cup of espresso made with the now clean machine without the tar inside!

wsfarrell
Posts: 497
Joined: 11 years ago

#2: Post by wsfarrell »

If moving the lever up or down is equivalent to 1 wheel revolution, I calculate that the wheel bearing grease in your Pavoni will be good for roughly 1.2 trillion years.

Would love to see pics of polish.

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rpavlis (original poster)
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Joined: 12 years ago

#3: Post by rpavlis (original poster) »

Here is the 1999 La Pavoni after polishing. I noticed that I had gotten a bit of polish on the steam control knob after getting the image:



The portafilter and drip tray are uncoated, as is the copper boiler. The boiler cap that I made myself is also not coated.

The properties of petroleum based wheel bearing grease for the handle result in less force being required to push the handle when the acorn nuts are adjusted because silicones have a very high molecular weight, and their viscosity is much more due to molecular entanglement than with hydrocarbon greases. I expect I will find the wheel bearing grease a better choice for the lever pivot points.