Almost done with the complete rebuild of a very ratty 1991 85-16M Practical machine.

I get the whole thing assembled and start pushing water into it. A couple leaks here and there at fittings - all fixed with a quick twist of the wrench. Everything seems fine except for a small noise of moving water... but there are no leaks that I can see. Looking, looking - can still hear the water moving. I turn off the valve for the boiler fill. Still a little bit of noise.

About 3 seconds later the overpressure valve and the antisyphon valve start spraying water all over the basement. Turns out that there is a leak in between the removable thermosyphon into the boiler. I have traced it to the lower/front connection which is, by matter of luck, the most complex and difficult to access.

So if someone has loads of La San Marco experience - please offer me some advice. Otherwise, you can take a look inside a small commercial machine.

Here is the view from the back of the machine. I took a wire wheel and polished all of the mating surfaces in the hope of solving my problem which it did not. I re-assembled it and it still leaks.



Here is the view of the inside. These are simply holes stamped in the flat sheet that makes up the boiler. You squish these areas flat when you tighten everything up.



Here is the view from the front. That thing with the big screw is an expansion valve. It opens to let water out when when heated in the thermosyphon.



Here are the parts out of the machine. This is not a mechanically simple thermosyphon to work with. Replaceable - yes. Simple - NO. Lots of threaded joints. Lots of gaskets. Hard to tighten/loosen when in the machine.



WES

Couple more notes:

- All gaskets are new and Teflon. I do need to triply check them now as one in particular has squished quite a bit during the multiple assembly/disassembly cycles. Probably going to replace them out of principle now.

- All mating surfaces are near polished at this point. It was a major battle to get the old paper/Klingerit ones out during the disassembly and there was some minor scratching but I got after it with the wire wheel and they look pretty good now.

- All parts are sequenced in assembly per this diagram - http://www.michaelo.com/documents/GROUPCIRCULATION85-16M.pdf

- I have tightened the daylights out of this thing multiple times. It still leaks although I can get the leak to move from one side of a joint to the other. There is no such thing as a good leak.

Will call a local shop tech to get some advice tomorrow.

This machine is actually looking pretty good otherwise:

San Marco machines have really nice, cast aluminum body panels. Nicest of any machine that I have worked on. These were powder coated a color to contrast the frame.



I took paint-remover to remove all of tattered yellow striped graphics that usually adorn these. Once I got down to the stainless, I refinished it in a matte.



This thing is pretty old for a dosing machine. I always worry about the brain on these things as they are hellaciously expensive to replace but this one fired right up.



Steel back panel with some saw dust. (1954 DeWalt RAS for anyone that knows what that is.) I repainted the logos.



There is a SM90 grinder that we powdercoated to match. Should be cool when they are all done.

WES

Kind of a sorry looking machine right now.



Whenever I first put water into a rebuild machine, I do it on that Metro rack shelf over my sink. It is a pretty good tip for anyone doing a complete rebuild. That or do it outside. There really are a lot of places and directions that water can leave one of these machines when you first power up. If I'm not feeling lucky, I might even cover the electrics with a Ziploc and wear goggles.

Here's another quirk on this machine that now cracks me up after I fixed it.

Someone as LSM woke up one morning and figured that they needed to locate a level sensor in this generation of machine. So instead of putting a hole in the top of the boiler and brazing in a fitting like you might normally see they did this....



They drilled two holes in the boiler door and created an attachment to hold the level probe. And not a simple attachment either - it is forged and hollow with two brazed on hollow yet partially threaded pegs that allow water and steam to circulate. The best, absolute best part of this attachment is that no technical documentation exists for it. No LSM manual or parts book that I have seen shows that it even could possibly exist. I tried installing it without gaskets and it dribbled almost immediately.

What to do? Espresso machine gaskets are rarely documented with detailed sizing so when nothing in my parts stash was close to fitting - I headed to my favorite place to get hard-to-find parts for espresso machines - NAPA. Those blue washers in there are Ford 302 Oversize Drain Plug Washers @ $0.69 each with a 12,000 mile warranty.



Of course there are brass nuts to hold it on. Thank god none of it was damaged, broken or lost during assembly. I would have brazed a fitting into the top for sure.