the sun is finally peeking out here in sydney after days of rain. it feels all clean and so does the microcimbali i have been pulling apart.
this is an early model (i presume), without the bolted top end to the piston body - the piston is removed from below. it also has a large single-piece bronze group head, which screws out of the main aluminium body. if you have one of these and are trying to find ways to disassemble it, look at this older thread - it is REALLY hard after years of corrosion....





and oddly enough, the top bronze bearing for the piston rod and for the lever action seems to have been flowed onto in place during the casting.... there are cup seals below this to the piston rod, so it is not a pressure connection.



this is the machine all apart on my bench. besides the bronze group head, everything was quite easy to get apart.



someone was at it before me - the sight glass was remade in perspex (!) and sealed with copious globules of silicon goo. also, the original drain pipe was likely busted and there is a broken-headed screw plug in a thread repair sealing the hole (if anyone knows where i can get a drain valve with original knob, please pm me!)





the boiler is in decent condition for aluminium - i have soaked it in dilute citric acid and given it a very gentle rub with scotch brite.



the threads to the bronze group head were corroded quite badly, but i have just cleaned them with a gentle wire brushing along the thread line. the two parts now go in by hand. the previous post linked to above shows a tool i had made to apply pressure to get the bronze group head off - LOTS of pressure and hammering and heating. the portafilter still goes in after removing a burr that occurred in the bronze from this reckless masculine pressure.



now it only remains to find the seals (i am asking at orphan espresso, but it is a strange machine and i think i may have to search far abroad) and maybe i will put the elements back in citric acid again to thoroughly descale. i do not plan to repaint - i want it working and as original as possible - i like the wear that tells of a thousand previous coffees made in decades past....

and i have to say, i really don't like aluminium....

Very cool: I love these total tear down threads. There is no sweeter shot of espresso than from a machine you've torn down and rebuilt yourself!

Been studying your seal situation and can't see a lot of difference with your early machine and the other MicroCimbali models. The sight glass seal is notched of course but the rod cup seal looks the same with a spacer and no metal clips or anything. Your piston has U cup seals but appears identical to the newer models which take 2 o ring seals and not u cup....if you insist on the u cups this may turn out to be a problem in the long run since it is my opinion that this design was not real good and they used the same piston and cylinder but changed to o rings for greater longevity. If you examine the cylinder insert you may see a taper at the lip which is there to avoid drag on the seals when they pass over the cylinder lip. Both of the seals basically come out of the cylinder when the piston is raised and they have to fit back in without catching or tearing so an o ring is a lot more successful and self entering the cylinder over and over than a u cup would be.
The upshot is that I think that your machine uses standard Microcimbali parts on the piston.

You may or may not be able to get that broken water faucet thread out of the aluminum without having to retap to a larger size, so a used faucet may not work out if you retap. You could consider a plug for the time being if you can get the remnant out. The faucet really does not act as a water source so much as a drain for the boiler. I think that it is there to allow the boiler to be completely drained between uses or during periods of non use to help avoid scale and pitting of the aluminum. As a hot water source it is fairly bogus.

doug,
greatly appreciated. i had wondered whether the lower u-cup ever left the piston body, letting the water in due to its reverse position (one was pointed up, to seal the water getting in i had thought, the other down, to let the water in and seal downwards allowing the pressure from the piston spring during a pull, but what you say makes sense....) i am very happy to try the o-rings out - i will order them in the next day. thanks so much for looking at this - i appreciate it - i know this machine is more of an orphan than may normally be the case....
i had heard the drain was there to be used after every use, leaving the boiler dry, lessening corrosion. maybe the designers knew this aluminium thing was going to get horrendous scale if water was left in - terrible!!!
cheers! i will order goodies and give the monster another try at life.

ps - honoured to be the recipient of your 1000th post - crikey!!!