Sticky lever on a Bezzera Family?

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tifoso in queens

#1: Post by tifoso in queens »

Hi everyone,

In the past few months, the lever on my Bezzera Family has started to stick a bit in the last five to ten seconds of the shot. The pull down is smooth and the flow itself is continuous throughout the shot--it is just that the lever itself lurches as it rises. I tried relubricating the seals, and it hasn't fixed it. Is this anything to be concerned about? I don't notice any difference in the shots, but I am curious to know why it is happening. Could it have anything to do with the swampy summer weather?

James

Paolo

#2: Post by Paolo »

Hi James,
How long have the current piston seals been in use?
Worn seals would be my guess.

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tifoso in queens (original poster)

#3: Post by tifoso in queens (original poster) »

A few years? They were installed by the previous owner so I'm not sure. But I just ordered new ones. Thanks!

tifoso in queens (original poster)

#4: Post by tifoso in queens (original poster) »

Well, I replaced the seals and it is still happening. Any other possibilities?

titan

#5: Post by titan »

Below someone mentioned that by fixing grind and tamp, they could resolve the issue on Elektra MCAL. In my local coffee shop, their lever also gets jerky sometimes at the end of the shot. I am assuming it is kind of a common problem with spring levers and probably does not have a unique solution.

Jerky Elektra Microcasa a Leva Action

baldheadracing
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#6: Post by baldheadracing »

As far as I can tell, there are only three possibilities once the seals have been replaced:
1. Seals not lubricated properly - see http://www.youtube.com/watch?v=MbHiIr3GCMs for an example (different group, but to get an idea)
2. Buildup on the cylinder surface, typically an almost-invisible layer of Calcium Carbonate. This can be scrubbed off by using a very soft (well-worn) cotton cloth soaked in vinegar. I would caution against stronger acids like citric acid and/or more abrasive cloths or paper towel.
3. Wear and/or polishing over time of the honed surface of the cylinder. I'd just live with this one.

tifoso in queens (original poster)

#7: Post by tifoso in queens (original poster) »

This is driving me crazy! After playing around with dosing (I basically stick to 14g doubles), I relubricated the seals per the video, adding a bit of Molykote to the top of the cylinder as shown in the video in case that mattered. Another user mentioned adding a small amount to the base of the spring, so I did that as well. Finally, I cleaned the cylinder with vinegar. Still sticking.

Here is the piston and spring.



I notice what seems to be a small amount of rust on the base of the spring and the piston itself. Could this be the problem? I have read all the thread about rusty springs and pistons, and it seems like you must disassemble the group to properly deal with this issue. Is this true?

(Edited thread title in case any owners of this machine have thoughts.)

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baldheadracing
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#8: Post by baldheadracing »

Is there some kind of buildup on the piston in the space between the seals? Hard to tell from the pic if that is just discoloration or something more.

BTW, rust is not a good sign, unfortunately. Does your cylinder wall look anything like the one in this post? Elektra Microcasa a Leva group problems

tifoso in queens (original poster)

#9: Post by tifoso in queens (original poster) »

Yes, it is a bit of buildup. I can't tell if it is rust or something else. Thankfully, the inside of my cylinder is pristine.

I am wondering if it is possible to soak the bottom of the group assembly in a cleaner, keeping the chrome parts out and avoiding taking it all apart. In other threads people have mentioned Joeglo, vinegar, and Naval Jelly. Any suggestions?

baldheadracing
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#10: Post by baldheadracing »

See how the brass piston is kindof dull, with a black tinge? That tinge is copper oxide. That copper oxide is keeping the lead that is in that brass out of your espresso. That (and a bit of limescale) is how they kept the lead at bay in the 1970's.

I'd take the seals off and scrub the piston with a mild non-scratch Scotch-brite kitchen pad.

More aggressive cleaners are going to remove the oxide.
RPavlis (RIP) outlined a procedure for sealing off the lead in that case - I did it here: Addressing Lead in pre-2014/2004 espresso machines