Clean that piston and dispersion screen

#1: Post by **gunman45** » October 21st, 2015, 12:39 pm

After the portafilter turned my Joe-Glo black. I did not expect anything less from my "new" purchase:

#2: Post by **DanoM** » October 21st, 2015, 1:47 pm

That's pretty! All you have to do is run hot water through that group and you get an "instant coffee"

October 21st, 2015, 4:32 pm

Yeah, it would taste like "instant coffee" brewed during the Vietnam era and only just now enjoyed....

#4: Post by **jpreiser** » October 21st, 2015, 5:22 pm

Mmm, coffee older than I am; sounds tasty.

#5: Post by **drgary** » October 22nd, 2015, 1:44 am

The hole in the piston rod also looks elongated.

#6: Post by **CoffeeBar** » October 22nd, 2015, 2:23 am

Wow, so dirty. My shower screen had badly damaged due the previous owner burn by fire torch to clean the coffee oil.

#7: Post by **CoffeeBar** » October 22nd, 2015, 2:25 am

drgary wrote:The hole in the piston rod also looks elongated.

Time to change piston rod???

October 22nd, 2015, 7:40 am

drgary wrote:The hole in the piston rod also looks elongated.

Optical illusion, you are seeing the "leading" edges of the pin hole which are beveled but the pin hole is still tight.

#9: Post by **rpavlis** » October 22nd, 2015, 7:59 am

This is one of the very good reasons why one should periodically disassemble the group and clean it very thoroughly! The other reason is that the the piston seals and seal on the top of the group need to be lubricated with "silicone" periodically, and the external moving parts of the lever assembly need to be lubricated with any of several high quality greases that are NOT silicone. It is a bad idea to go for long periods without both of these lubrication operations.

Another thing one can use to clean the accumulated "gunk" from the internal group parts is a bit of 190 proof ethanol, often sold as "Everclear".

It is amazing how much improvement in espresso taste and in mechanical operation there is after such a group servicing when the servicing has been delayed too long!!! I find that I can judge the force required to move the handle when the machine is cold and unpressurised and use that information to indicate when it is time for such a cleaning and servicing.

#10: Post by **OldNuc** » October 22nd, 2015, 8:20 am

drgary wrote:The hole in the piston rod also looks elongated.

That my be from the chamfer and the angle of the picture. Looks OK to me without measuring it.

With heavy use of these La Pavoni machines an every 2 week or so relube and screen clean is a good idea. Over lubing with lube will not lengthen this interval but it does make a nice silicone oil slick on the coffee surface.