Hello,

A few weeks ago a member posted a few issues regarding an older MCal, including a sticky piston. The thread can be found here. But most importantly, a video he made: http://youtu.be/JfbVS42fLzI

I'm now seeing the exact same behaviour with my 2006 MCal. Prior to changing the seals, the machine had developed some leak (water would spill out a small hole behind the group when pulling), but was working fine. The new seals were original Elektra I had just ordered from Stefano's. I thoroughly cleaned the piston and group using a solution of Joe Glo (a backflush detergent), lubricated the piston, the seals and the interior of the group's cylinder with dow 111. I've been using the machine with this behaviour for nearly 2 weeks now, expecting that some coffee oil would complement the lubrication but it seems to be getting very slightly worse (at least, not better).

Yesterday, I've opened up the group and using a flashlight looked more carefully at the surface of the cylinder. There are some pitting but it seems very very superficial. Under the finger, it feels like slightly depolished metal. I've tried sanding it with 2000 grit wet paper (only using fingers), then cleaning and lubricating again. The movement feels a bit less rough but is still "sticky".

Any suggestion on how to proceed from here? I'm a bit reluctant at trying 1000 grit paper or figuring out a way to mount the paper on a drill-powered cylinder to provide a more thorough sanding. If I go the sanding route, anyone would have hands-on experience to how fine I should polish?

This seems very strange. There are several questions that come to my mind. Dimethylsiloxane polymers are insoluble in most other high molecular weight oils. Could there be a problem with their being other types of lubricant in the system in addition to the Dow 111 product? When you were putting the piston assembly back into the machine did the piston move down smoothly with very little resistence? Is the area of contact between the piston rod and the top of the cap properly lubricated? The walls of the cylinder of the one I have is very very smooth. Do you use water with high chloride content? Do you have ultra hard, ultra basic, or ultra acidic water? Do you use the machine regularly?

It seems strange that it is giving problems.

Thanks for you rapid feedback! Here are the answers to your questions and a few extra info that might be relevant.

I've been lubricating the piston rod and the little roller on the lever with Orphan espresso's "lever pin lube". I've used it rather sparingly but as it is quite fluid, it might reach the inside of the cylinder. If it was a case of dow 111 reacting (solidifying?) with another lubricant, how should I clean it? Water and soap? From touching the inside of the cylinder, there seem to be no lubricant at all left once the piston assembly is pulled out. The seals are extremely tight, I can't figure out how they would let any sort of lubricant on the cylinder wall!

When putting back the piston assembly, I need to apply a significant amount of force to push the piston down, it feels smooth. Probably equivalent to the force necessary for pulling down the lever.

As I've found the piston rod a bit "dry", I've just tried adding some of the "lever pin lube". I've noticed the that the lever has a smooth action when the machine is cold. But once the machine heats up, I start to hear the seals squeak and the movement becomes slightly jerky.

Following my little sanding (2000-grit), the inside of the cylinder is perfectly smooth under the finger.

I use Montreal's tap water. (Which I'm frequently testing for aquarium purpose!) It has a pH between 7.5-7.8, hardness around 150 ppm and chorines at about 25 ppm. I use the machine daily for 4 to 6 shots, since 2006, this is my third set of seals and I also performed the previous seal change. I've just realized that last time I changed the seals (in 2009), I've bought them from Orphan espresso... I can't see that this would matter...

Are the walls of the group cylinder smooth?

How often has the cylinder been removed and cleaned?

See Elektra Microcasa a Leva group problems

I typically only remove piston when changing seals, once every 2-3 years maybe. I have seen no dark pitting such as what was seen in number9's photo. Under the finger I could feel some "texture", which is why I tried a very light sanding. The cylinder is now extremely smooth.

The process you describe (salt accumulating above the top seal) would only happen once the seal is compromised. The machine is really not fun to use once this happens (water spilling from the backside vent). I could not imagine someone going on using the machine for extended time once the top seal has started to leak.

The squeaky behaviour also didn't built up. It was not there at all with the old seals and appeared instantly with the new seals installed. Unfortunately, I removed the old seals by cutting them so I can't test them back.

Robert's giving you great help here. To address one part of the problem, you could try using Dow 111 to lubricate the pins and rod too. It may be a little stiff before warmup but after that you'll be okay. At least that's how I lube my MCAL and it works fine.

I cringe when ever I hear of someone sanding a cylinder, go to an auto parts store and get a brake hone and hone the cylinder. Moveing it up and down the cylinder while spinning it slowly with a drill. This action will cross hatch the cylinder making the piston and seals ride in smoothness, not in a sort of groove from the previous seals. Try this out next time you think you need to sand the cylinder.

Have the same problem: piston worked perfectly until I changed the washers (bought a washer replacement set from Stefano's). When I let go the lever it runs smoothly for about 10 cms then begins to jerk its way through the run. When it gets almost to the end of its travel it stops completely for about three seconds then finishes off with a tremendous jerk and bang!

There is no obvious pitting of the cylinder wall; I followed Stefano's instructions in replacing the washers, my water is neither very soft nor very hard and I've removed the piston and greased and regreased the washers, the piston rod and the little pin that acts as a fulcrum for the rod. Nothing helps.

Does not stick when there is no coffee in the basket i.e. when I flush it etc. The lubricant I have used regularly, until now without problems, is Haynes Lubri-film.

Have had my Microcasa Elektra for three+ years with no previous problems except the water leak which necessitated my changing the washers.

Any suggestions? Apart from junking the machine?

Have you asked Stefano about this? He's very knowledgeable and responsive. And there's certainly no need to junk an MCAL that's got tight seals.

Yes I contacted Stefano's but all they could suggest was to lubricate the washers. Not a lot of help. Other than changing the washers I have done nothing to alter the machine; it worked well until the new washers: ergo the washers or their placement must be the culprits. But how to cure it ....?